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Huldrych Zwingli

Huldrych or Ulrich Zwingli (1 January 1484 – 11 October 1531) was a leader of the Reformation in Switzerland, born during a time of emerging Swiss patriotism and increasing criticism of the Swiss mercenary system. He attended the University of Vienna and the University of Basel, a scholarly center of Renaissance humanism. He continued his studies while he served as a pastor in Glarus and later in Einsiedeln, where he was influenced by the writings of Erasmus.

In 1519, Zwingli became the Leutpriester (people's priest) of the Grossmünster in Zürich where he began to preach ideas on reform of the Catholic Church. In his first public controversy in 1522, he attacked the custom of fasting during Lent. In his publications, he noted corruption in the ecclesiastical hierarchy, promoted clerical marriage, and attacked the use of images in places of worship. Among his most notable contributions to the Reformation was his expository preaching, starting in 1519, through the Gospel of Matthew, before eventually using Biblical exegesis to go through the entire New Testament, a radical departure from the Catholic mass. In 1525, he introduced a new communion liturgy to replace the Mass. He also clashed with the Anabaptists, which resulted in their persecution. Historians have debated whether or not he turned Zürich into a theocracy.

The Reformation spread to other parts of the Swiss Confederation, but several cantons resisted, preferring to remain Catholic. Zwingli formed an alliance of Reformed cantons which divided the Confederation along religious lines. In 1529, a war was averted at the last moment between the two sides. Meanwhile, Zwingli's ideas came to the attention of Martin Luther and other reformers. They met at the Marburg Colloquy and agreed on many points of doctrine, but they could not reach an accord on the doctrine of the Real Presence of Christ in the Eucharist.

In 1531, Zwingli's alliance applied an unsuccessful food blockade on the Catholic cantons. The cantons responded with an attack at a moment when Zürich was ill-prepared, and Zwingli died on the battlefield. His legacy lives on in the confessions, liturgy, and church orders of the Reformed churches of today.

Historical context
The Swiss Confederation in Huldrych Zwingli's time consisted of thirteen states (cantons) as well as affiliated areas and common lordships. Unlike the modern state of Switzerland, which operates under a federal government, each of the thirteen cantons was nearly independent, conducting its own domestic and foreign affairs. Each canton formed its own alliances within and without the Confederation. This relative independence served as the basis for conflict during the time of the Reformation when the various cantons divided between different confessional camps. Military ambitions gained an additional impetus with the competition to acquire new territory and resources, as seen for example in the Old Zürich War of 1440–1446.

The wider political environment in Europe during the 15th and 16th centuries was also volatile. For centuries the relationship with the Confederation's powerful neighbour, France, determined the foreign policies of the Swiss. Nominally, the Confederation formed a part of the Holy Roman Empire. However, through a succession of wars culminating in the Swabian War in 1499, the Confederation had become de facto independent. As the two continental powers and minor regional states such as the Duchy of Milan, the Duchy of Savoy, and the Papal States competed and fought against each other, there were far-reaching political, economic, and social consequences for the Confederation. During this time the mercenary pension system became a subject of disagreement. The religious factions of Zwingli's time debated vociferously the merits of sending young Swiss men to fight in foreign wars mainly for the enrichment of the cantonal authorities.

These internal and external factors contributed to the rise of a Confederation national consciousness, in which the term fatherland (patria) began to take on meaning beyond a reference to an individual canton. At the same time, Renaissance humanism, with its universal values and emphasis on scholarship (as exemplified by Erasmus (1466–1536), the "prince of humanism"), had taken root in the Confederation. Within this environment, defined by the confluence of Swiss patriotism and humanism, Zwingli was born in 1484.

Early years (1484–1518)
Huldrych Zwingli was born on 1 January 1484 in Wildhaus, in the Toggenburg valley of Switzerland, to a family of farmers, the third child of eleven. His father, Ulrich, played a leading role in the administration of the community (Amtmann or chief local magistrate). Zwingli's primary schooling was provided by his uncle, Bartholomew, a cleric in Weesen, where he probably met Katharina von Zimmern. At ten years old, Zwingli was sent to Basel to obtain his secondary education where he learned Latin under Magistrate Gregory Bünzli. After three years in Basel, he stayed a short time in Bern with the humanist Henry Wölfflin. The Dominicans in Bern tried to persuade Zwingli to join their order and it is possible that he was received as a novice.

However, his father and uncle disapproved of such a course and he left Bern without completing his Latin studies. He enrolled in the University of Vienna in the winter semester of 1498 but was expelled, according to the university's records. However, it is not certain that Zwingli was indeed expelled, and he re-enrolled in the summer semester of 1500; his activities in 1499 are unknown. Zwingli continued his studies in Vienna until 1502, after which he transferred to the University of Basel where he received the Master of Arts degree (Magister) in 1506. In Basel, one of Zwingli's teachers was Thomas Wyttenbach from Biel, with whom he later corresponded on the doctrine of transubstantiation.

Zwingli was ordained in Constance, the seat of the local diocese, and he celebrated his first Mass in his hometown, Wildhaus, on 29 September 1506. As a young priest he had studied little theology, but this was not considered unusual at the time. His first ecclesiastical post was the pastorate of the town of Glarus, where he stayed for ten years. It was in Glarus, whose soldiers were used as mercenaries in Europe, that Zwingli became involved in politics. The Swiss Confederation was embroiled in various campaigns with its neighbours: the French, the Habsburgs, and the Papal States. Zwingli placed himself solidly on the side of the Roman See. In return, Pope Julius II honoured Zwingli by providing him with an annual pension. He took the role of chaplain in several campaigns in Italy, including the Battle of Novara in 1513.

However, the decisive defeat of the Swiss in the Battle of Marignano caused a shift in mood in Glarus in favour of the French rather than the pope. Zwingli, the papal partisan, found himself in a difficult position and he decided to retreat to Einsiedeln in the canton of Schwyz. By this time, he had become convinced that mercenary service was immoral and that Swiss unity was indispensable for any future achievements. Some of his earliest extant writings, such as The Ox (1510) and The Labyrinth (1516), attacked the mercenary system using allegory and satire. His countrymen were presented as virtuous people within a French, imperial, and papal triangle.

Zwingli stayed in Einsiedeln for two years during which he withdrew completely from politics in favour of ecclesiastical activities and personal studies. His time as pastor of Glarus and Einsiedeln was characterized by inner growth and development. He perfected his Greek and he took up the study of Hebrew. His library contained over three hundred volumes from which he was able to draw upon classical, patristic, and scholastic works. He exchanged scholarly letters with a circle of Swiss humanists and began to study the writings of Erasmus. Zwingli took the opportunity to meet him while Erasmus was in Basel between August 1514 and May 1516. Zwingli's turn to relative pacifism and his focus on preaching can be traced to the influence of Erasmus.

In late 1518, the post of the Leutpriestertum (people's priest) of the Grossmünster at Zürich became vacant. The canons of the foundation that administered the Grossmünster recognised Zwingli's reputation as a fine preacher and writer. His connection with humanists was a decisive factor as several canons were sympathetic to Erasmian reform. In addition, his opposition to the French and to mercenary service was welcomed by Zürich politicians. On 11 December 1518, the canons elected Zwingli to become the stipendiary priest and on 27 December he moved permanently to Zürich.

Beginning of Zürich ministry (1519–1521)
On 1 January 1519, Zwingli gave his first sermon in Zürich. Deviating from the prevalent practice of basing a sermon on the Gospel lesson of a particular Sunday, Zwingli, using Erasmus' New Testament as a guide, began to read through the Gospel of Matthew, giving his interpretation during the sermon, known as the method of lectio continua. He continued to read and interpret the book on subsequent Sundays until he reached the end and then proceeded in the same manner with the Acts of the Apostles, the New Testament epistles, and finally the Old Testament. His motives for doing this are not clear, but in his sermons he used exhortation to achieve moral and ecclesiastical improvement which were goals comparable with Erasmian reform. Sometime after 1520, Zwingli's theological model began to evolve into an idiosyncratic form that was neither Erasmian nor Lutheran. Scholars do not agree on the process of how he developed his own unique model. One view is that Zwingli was trained as an Erasmian humanist and Luther played a decisive role in changing his theology.

Another view is that Zwingli did not pay much attention to Luther's theology and in fact he considered it as part of the humanist reform movement. A third view is that Zwingli was not a complete follower of Erasmus, but had diverged from him as early as 1516 and that he independently developed his theology.

Zwingli's theological stance was gradually revealed through his sermons. He attacked moral corruption and in the process he named individuals who were the targets of his denunciations. Monks were accused of indolence and high living. In 1519, Zwingli specifically rejected the veneration of saints and called for the need to distinguish between their true and fictional accounts. He cast doubts on hellfire, asserted that unbaptised children were not damned, and questioned the power of excommunication. His attack on the claim that tithing was a divine institution, however, had the greatest theological and social impact. This contradicted the immediate economic interests of the foundation. One of the elderly canons who had supported Zwingli's election, Konrad Hofmann, complained about his sermons in a letter. Some canons supported Hofmann, but the opposition never grew very large. Zwingli insisted that he was not an innovator and that the sole basis of his teachings was Scripture.

Within the diocese of Constance, Bernhardin Sanson was offering a special indulgence for contributors to the building of St Peter's in Rome. When Sanson arrived at the gates of Zürich at the end of January 1519, parishioners prompted Zwingli with questions. He responded with displeasure that the people were not being properly informed about the conditions of the indulgence and were being induced to part with their money on false pretences. This was over a year after Martin Luther published his Ninety-five theses (31 October 1517). The council of Zürich refused Sanson entry into the city. As the authorities in Rome were anxious to contain the fire started by Luther, the Bishop of Constance denied any support of Sanson and he was recalled.

In August 1519, Zürich was struck by an outbreak of the plague during which at least one in four persons died. All of those who could afford it left the city, but Zwingli remained and continued his pastoral duties. In September, he caught the disease and nearly died. He described his preparation for death in a poem, Zwingli's Pestlied, consisting of three parts: the onset of the illness, the closeness to death, and the joy of recovery. The final verses of the first part read:

In the years following his recovery, Zwingli's opponents remained in the minority. When a vacancy occurred among the canons of the Grossmünster, Zwingli was elected to fulfill that vacancy on 29 April 1521. In becoming a canon, he became a full citizen of Zürich. He also retained his post as the people's priest of the Grossmünster.

First rifts (1522–1524)
The first public controversy regarding Zwingli's preaching broke out during the season of Lent in 1522. On the first fasting Sunday, 9 March, Zwingli and about a dozen other participants consciously transgressed the fasting rule by cutting and distributing two smoked sausages (the Wurstessen in Christoph Froschauer's workshop). Zwingli defended this act in a sermon which was published on 16 April, under the title Von Erkiesen und Freiheit der Speisen (Regarding the Choice and Freedom of Foods). He noted that no general valid rule on food can be derived from the Bible and that to transgress such a rule is not a sin. The event, which came to be referred to as the Affair of the Sausages, is considered to be the start of the Reformation in Switzerland.

Even before the publication of this treatise, the diocese of Constance reacted by sending a delegation to Zürich. The city council condemned the fasting violation, but assumed responsibility over ecclesiastical matters and requested the religious authorities clarify the issue. The bishop responded on 24 May by admonishing the Grossmünster and city council and repeating the traditional position.

Following this event, Zwingli and other humanist friends petitioned the bishop on 2 July to abolish the requirement of celibacy on the clergy. Two weeks later the petition was reprinted for the public in German as Eine freundliche Bitte und Ermahnung an die Eidgenossen (A Friendly Petition and Admonition to the Confederates). The issue was not just an abstract problem for Zwingli, as he had secretly married a widow, Anna Reinhart, earlier in the year. Their cohabitation was well-known and their public wedding took place on 2 April 1524, three months before the birth of their first child. They would have four children: Regula, William, Huldrych, and Anna. As the petition was addressed to the secular authorities, the bishop responded at the same level by notifying the Zürich government to maintain the ecclesiastical order. Other Swiss clergymen joined in Zwingli's cause which encouraged him to make his first major statement of faith, Apologeticus Archeteles (The First and Last Word). He defended himself against charges of inciting unrest and heresy. He denied the ecclesiastical hierarchy any right to judge on matters of church order because of its corrupted state.

Zürich disputations (1523)
The events of 1522 brought no clarification on the issues. Not only did the unrest between Zürich and the bishop continue, tensions were growing among Zürich's Confederation partners in the Swiss Diet. On 22 December, the Diet recommended that its members prohibit the new teachings, a strong indictment directed at Zürich. The city council felt obliged to take the initiative and find its own solution.

First Disputation
On 3 January 1523, the Zürich city council invited the clergy of the city and outlying region to a meeting to allow the factions to present their opinions. The bishop was invited to attend or to send a representative. The council would render a decision on who would be allowed to continue to proclaim their views. This meeting, the first Zürich disputation, took place on 29 January 1523.

The meeting attracted a large crowd of approximately six hundred participants. The bishop sent a delegation led by his vicar general, Johannes Fabri. Zwingli summarised his position in the Schlussreden (Concluding Statements or the Sixty-seven Articles). Fabri, who had not envisaged an academic disputation in the manner Zwingli had prepared for, was forbidden to discuss high theology before laymen, and simply insisted on the necessity of the ecclesiastical authority. The decision of the council was that Zwingli would be allowed to continue his preaching and that all other preachers should teach only in accordance with Scripture.

Second Disputation
In September 1523, Leo Jud, Zwingli's closest friend and colleague and pastor of St Peterskirche, publicly called for the removal of statues of saints and other icons. This led to demonstrations and iconoclastic activities. The city council decided to work out the matter of images in a second disputation. The essence of the mass and its sacrificial character was also included as a subject of discussion. Supporters of the mass claimed that the eucharist was a true sacrifice, while Zwingli claimed that it was a commemorative meal. As in the first disputation, an invitation was sent out to the Zürich clergy and the bishop of Constance. This time, however, the lay people of Zürich, the dioceses of Chur and Basel, the University of Basel, and the twelve members of the Confederation were also invited. About nine hundred persons attended this meeting, but neither the bishop nor the Confederation sent representatives. The disputation started on 26 October 1523 and lasted two days.

Zwingli again took the lead in the disputation. His opponent was the aforementioned canon, Konrad Hofmann, who had initially supported Zwingli's election. Also taking part was a group of young men demanding a much faster pace of reformation, who among other things pleaded for replacing infant baptism with adult baptism. This group was led by Conrad Grebel, one of the initiators of the Anabaptist movement. During the first three days of dispute, although the controversy of images and the mass were discussed, the arguments led to the question of whether the city council or the ecclesiastical government had the authority to decide on these issues.

At this point, Konrad Schmid, a priest from Aargau and follower of Zwingli, made a pragmatic suggestion. As images were not yet considered to be valueless by everyone, he suggested that pastors preach on this subject under threat of punishment. He believed the opinions of the people would gradually change and the voluntary removal of images would follow. Hence, Schmid rejected the radicals and their iconoclasm, but supported Zwingli's position. In November the council passed ordinances in support of Schmid's motion. Zwingli wrote a booklet on the evangelical duties of a minister, Kurze, christliche Einleitung (Short Christian Introduction), and the council sent it out to the clergy and the members of the Confederation.

Reformation progresses in Zürich (1524–1525)
Huldrych Zwingli was a major figure in the Swiss Reformation, advocating for the authority of scripture and the rejection of religious practices not supported by the Bible. His preaching and teachings helped spread Reformation ideas beyond Switzerland and influenced the development of Protestantism throughout Europe. In December 1523, the council set a deadline of Pentecost in 1524 for a solution to the elimination of the Mass and images. Zwingli gave a formal opinion in Vorschlag wegen der Bilder und der Messe (Proposal Concerning Images and the Mass). He did not urge an immediate, general abolition. The council decided on the orderly removal of images within Zürich, but rural congregations were granted the right to remove them based on majority vote. The decision on the Mass was postponed.

Evidence of the effect of the Reformation was seen in early 1524. Candlemas was not celebrated, processions of robed clergy ceased, worshippers did not go with palms or relics on Palm Sunday to the Lindenhof, and triptychs remained covered and closed after Lent. Opposition to the changes came from Konrad Hofmann and his followers, but the council decided in favour of keeping the government mandates. When Hofmann left the city, opposition from pastors hostile to the Reformation broke down. The bishop of Constance tried to intervene in defending the Mass and the veneration of images. Zwingli wrote an official response for the council and the result was the severance of all ties between the city and the diocese.

Although the council had hesitated in abolishing the Mass, the decrease in the exercise of traditional piety allowed pastors to be unofficially released from the requirement of celebrating Mass. As individual pastors altered their practices as each saw fit, Zwingli was prompted to address this disorganised situation by designing a communion liturgy in the German language. This was published in Aktion oder Brauch des Nachtmahls (Act or Custom of the Supper). Shortly before Easter, Zwingli and his closest associates requested the council to cancel the Mass and to introduce the new public order of worship.

On Maundy Thursday, 13 April 1525, Zwingli celebrated communion under his new liturgy. Wooden cups and plates were used to avoid any outward displays of formality. The congregation sat at set tables to emphasise the meal aspect of the sacrament. The sermon was the focal point of the service and there was no organ music or singing. The importance of the sermon in the worship service was underlined by Zwingli's proposal to limit the celebration of communion to four times a year.

For some time Zwingli had accused mendicant orders of hypocrisy and demanded their abolition in order to support the truly poor. He suggested the monasteries be changed into hospitals and welfare institutions and incorporate their wealth into a welfare fund. This was done by reorganising the foundations of the Grossmünster and Fraumünster and pensioning off remaining nuns and monks. The council secularised the church properties (Fraumünster handed over to the city of Zurich by Zwingli's acquaintance Katharina von Zimmern in 1524) and established new welfare programs for the poor.

Zwingli requested permission to establish a Latin school, the Prophezei (Prophecy) or Carolinum, at the Grossmünster. The council agreed and it was officially opened on 19 June 1525 with Zwingli and Jud as teachers. It served to retrain and re-educate the clergy. The Zürich Bible translation, traditionally attributed to Zwingli and printed by Christoph Froschauer, bears the mark of teamwork from the Prophecy school. Scholars have not yet attempted to clarify Zwingli's share of the work based on external and stylistic evidence.

Conflict with the Anabaptists (1525–1527)
Shortly after the second Zürich disputation, many in the radical wing of the Reformation became convinced that Zwingli was making too many concessions to the Zürich council. They rejected the role of civil government and demanded the immediate establishment of a congregation of the faithful. Conrad Grebel, the leader of the radicals and the emerging Anabaptist movement, spoke disparagingly of Zwingli in private. On 15 August 1524 the council insisted on the obligation to baptise all newborn infants. Zwingli secretly conferred with Grebel's group and late in 1524, the council called for official discussions. When talks were broken off, Zwingli published Wer Ursache gebe zu Aufruhr (Whoever Causes Unrest) clarifying the opposing points of view. On 17 January 1525 a public debate was held and the council decided in favour of Zwingli. Anyone refusing to have their children baptised was required to leave Zürich. The radicals ignored these measures and on 21 January, they met at the house of the mother of another radical leader, Felix Manz. Grebel and a third leader, George Blaurock, performed the first recorded Anabaptist adult baptisms.

On 2 February, the council repeated the requirement on the baptism of all babies and some who failed to comply were arrested and fined, Manz and Blaurock among them. Zwingli and Jud interviewed them and more debates were held before the Zürich council. Meanwhile, the new teachings continued to spread to other parts of the Confederation as well as a number of Swabian towns. On 6–8 November, the last debate on the subject of baptism took place in the Grossmünster. Grebel, Manz, and Blaurock defended their cause before Zwingli, Jud, and other reformers. There was no serious exchange of views as each side would not move from their positions and the debates degenerated into an uproar, each side shouting abuse at the other.

The Zürich council decided that no compromise was possible. On 7 March 1526 it released the notorious mandate that no one shall rebaptise another under the penalty of death. Although Zwingli, technically, had nothing to do with the mandate, there is no indication that he disapproved. Felix Manz, who had sworn to leave Zürich and not to baptise any more, had deliberately returned and continued the practice. After he was arrested and tried, he was executed on 5 January 1527 by being drowned in the Limmat. He was the first Anabaptist martyr; three more were to follow, after which all others either fled or were expelled from Zürich.

Reformation in the Confederation (1526–1528)
On 8 April 1524, five cantons, Lucerne, Uri, Schwyz, Unterwalden, and Zug, formed an alliance, die fünf Orte (the Five States) to defend themselves from Zwingli's Reformation. They contacted the opponents of Martin Luther including John Eck, who had debated Luther in the Leipzig Disputation of 1519. Eck offered to dispute Zwingli and he accepted. However, they could not agree on the selection of the judging authority, the location of the debate, and the use of the Swiss Diet as a court. Because of the disagreements, Zwingli decided to boycott the disputation. On 19 May 1526, all the cantons sent delegates to Baden. Although Zürich's representatives were present, they did not participate in the sessions. Eck led the Catholic party while the reformers were represented by Johannes Oecolampadius of Basel, a theologian from Württemberg who had carried on an extensive and friendly correspondence with Zwingli. While the debate proceeded, Zwingli was kept informed of the proceedings and printed pamphlets giving his opinions. It was of little use as the Diet decided against Zwingli. He was to be banned and his writings were no longer to be distributed. Of the thirteen Confederation members, Glarus, Solothurn, Fribourg, and Appenzell as well as the Five States voted against Zwingli. Bern, Basel, Schaffhausen, and Zürich supported him.

The Baden disputation exposed a deep rift in the Confederation on matters of religion. The Reformation was now emerging in other states. The city of St Gallen, an affiliated state to the Confederation, was led by a reformed mayor, Joachim Vadian, and the city abolished the mass in 1527, just two years after Zürich. In Basel, although Zwingli had a close relationship with Oecolampadius, the government did not officially sanction any reformatory changes until 1 April 1529 when the mass was prohibited. Schaffhausen, which had closely followed Zürich's example, formally adopted the Reformation in September 1529.

In the case of Bern, Berchtold Haller, the priest at St Vincent Münster, and Niklaus Manuel, the poet, painter, and politician, had campaigned for the reformed cause. But it was only after another disputation that Bern counted itself as a canton of the Reformation. Three hundred and fifty persons participated, including pastors from Bern and other cantons as well as theologians from outside the Confederation such as Martin Bucer and Wolfgang Capito from Strasbourg, Ambrosius Blarer from Constance, and Andreas Althamer from Nuremberg. Eck and Fabri refused to attend and the Catholic cantons did not send representatives. The meeting started on 6 January 1528 and lasted nearly three weeks. Zwingli assumed the main burden of defending the Reformation and he preached twice in the Münster. On 7 February 1528 the council decreed that the Reformation be established in Bern.

First Kappel War (1529)
Even before the Bern Disputation, Zwingli was canvassing for an alliance of reformed cities. Once Bern officially accepted the Reformation, a new alliance, das Christliche Burgrecht (the Christian Civic Union) was created. The first meetings were held in Bern between representatives of Bern, Constance, and Zürich on 5–6 January 1528. Other cities, including Basel, Biel, Mülhausen, Schaffhausen, and St Gallen, eventually joined the alliance. The Five (Catholic) States felt encircled and isolated, so they searched for outside allies. After two months of negotiations, the Five States formed die Christliche Vereinigung (the Christian Alliance) with Ferdinand of Austria on 22 April 1529.

Soon after the Austrian treaty was signed, a reformed preacher, Jacob Kaiser, was captured in Uznach and executed in Schwyz. This triggered a strong reaction from Zwingli; he drafted Ratschlag über den Krieg (Advice About the War) for the government. He outlined justifications for an attack on the Catholic states and other measures to be taken. Before Zürich could implement his plans, a delegation from Bern that included Niklaus Manuel arrived in Zürich. The delegation called on Zürich to settle the matter peacefully. Manuel added that an attack would expose Bern to further dangers as Catholic Valais and the Duchy of Savoy bordered its southern flank. He then noted, "You cannot really bring faith by means of spears and halberds." Zürich, however, decided that it would act alone, knowing that Bern would be obliged to acquiesce. War was declared on 8 June 1529. Zürich was able to raise an army of 30,000 men. The Five States were abandoned by Austria and could raise only 9,000 men. The two forces met near Kappel, but war was averted due to the intervention of Hans Aebli, a relative of Zwingli, who pleaded for an armistice.

Zwingli was obliged to state the terms of the armistice. He demanded the dissolution of the Christian Alliance; unhindered preaching by reformers in the Catholic states; prohibition of the pension system; payment of war reparations; and compensation to the children of Jacob Kaiser. Manuel was involved in the negotiations. Bern was not prepared to insist on the unhindered preaching or the prohibition of the pension system. Zürich and Bern could not agree and the Five (Catholic) States pledged only to dissolve their alliance with Austria. This was a bitter disappointment for Zwingli and it marked his decline in political influence. The first Land Peace of Kappel, der erste Landfriede, ended the war on 24 June.

Marburg Colloquy (1529)
While Zwingli carried on the political work of the Swiss Reformation, he developed his theological views with his colleagues. The famous disagreement between Luther and Zwingli on the interpretation of the eucharist originated when Andreas Karlstadt, Luther's former colleague from Wittenberg, published three pamphlets on the Lord's Supper in which Karlstadt rejected the idea of a real presence in the elements. These pamphlets, published in Basel in 1524, received the approval of Oecolampadius and Zwingli. Luther rejected Karlstadt's arguments and considered Zwingli primarily to be a partisan of Karlstadt. Zwingli began to express his thoughts on the eucharist in several publications including de Eucharistia (On the Eucharist). Understanding that Christ had ascended to heaven and was sitting at the Father's right hand, Zwingli criticized the idea that Christ's humanity could be in two places at once. Unlike his divinity, Christ's human body was not omnipresent and so could not be in heaven and at the same time be present in the elements. Timothy George, evangelical author, editor of Christianity Today and professor of Historical Theology at Beeson Divinity School at Samford University, has refuted a long-standing misreading of Zwingli that erroneously claimed the Reformer denied all notions of real presence and believed in a memorial view of the Supper, where it was purely symbolic.

By spring 1527, Luther reacted strongly to Zwingli's views in the treatise ''Dass Diese Worte Christi "Das ist mein Leib etc." noch fest stehen wider die Schwarmgeister'' (That These Words of Christ "This is My Body etc." Still Stand Firm Against the Fanatics). The controversy continued until 1528 when efforts to build bridges between the Lutheran and the Zwinglian views began. Martin Bucer tried to mediate while Philip of Hesse, who wanted to form a political coalition of all Protestant forces, invited the two parties to Marburg to discuss their differences. This event became known as the Marburg Colloquy.

Zwingli accepted Philip's invitation fully believing that he would be able to convince Luther. In contrast, Luther did not expect anything to come out of the meeting and had to be urged by Philip to attend. Zwingli, accompanied by Oecolampadius, arrived on 28 September 1529, with Luther and Philipp Melanchthon arriving shortly thereafter. Other theologians also participated including Martin Bucer, Andreas Osiander, Johannes Brenz, and Justus Jonas.

The debates were held from 1–4 October and the results were published in the fifteen Marburg Articles. The participants were able to agree on fourteen of the articles, but the fifteenth article established the differences in their views on the presence of Christ in the eucharist. Professor George summarized the incompatible views, "On this issue, they parted without having reached an agreement. Both Luther and Zwingli agreed that the bread in the Supper was a sign. For Luther, however, that which the bread signified, namely the body of Christ, was present "in, with, and under" the sign itself. For Zwingli, though, sign and thing signified were separated by a distance—the width between heaven and earth."

"'Luther claimed that the body of Christ was not eaten in a gross, material way but rather in some mysterious way, which is beyond human understanding. Yet, Zwingli replied, if the words were taken in their literal sense, the body had to be eaten in the most grossly material way. 'For this is the meaning they carry: this bread is that body of mine which is given for you. It was given for us in grossly material form, subject to wounds, blows and death. As such, therefore, it must be the material of the supper.' Indeed, to press the literal meaning of the text even farther, it follows that Christ would have again to suffer pain, as his body was broken again—this time by the teeth of communicants. Even more absurdly, Christ's body would have to be swallowed, digested, even eliminated through the bowels! Such thoughts were repulsive to Zwingli. They smacked of cannibalism on the one hand and of the pagan mystery religions on the other. The main issue for Zwingli, however, was not the irrationality or exegetical fallacy of Luther's views. It was rather that Luther put 'the chief point of salvation in physically eating the body of Christ,' for he connected it with the forgiveness of sins. The same motive that had moved Zwingli so strongly to oppose images, the invocation of saints, and baptismal regeneration was present also in the struggle over the Supper: the fear of idolatry. Salvation was by Christ alone, through faith alone, not through faith and bread. The object of faith was that which is not seen (Heb 11:1) and which therefore cannot be eaten except, again, in a nonliteral, figurative sense. 'Credere est edere,' said Zwingli: 'To believe is to eat.' To eat the body and to drink the blood of Christ in the Supper, then, simply meant to have the body and blood of Christ present in the mind.'"

The failure to find agreement resulted in strong emotions on both sides. "When the two sides departed, Zwingli cried out in tears, "There are no people on earth with whom I would rather be at one than the [Lutheran] Wittenbergers.""

Due to these differences, Luther initially refused to acknowledge Zwingli and his followers as Christians.

Politics, confessions, the Kappel Wars and death (1529–1531)
With the failure of the Marburg Colloquy and the split of the Confederation, Zwingli set his goal on an alliance with Philip of Hesse. He kept up a lively correspondence with Philip. Bern refused to participate, but after a long process, Zürich, Basel, and Strasbourg signed a mutual defence treaty with Philip in November 1530. Zwingli also personally negotiated with France's diplomatic representative, but the two sides were too far apart. France wanted to maintain good relations with the Five States. Approaches to Venice and Milan also failed.

As Zwingli was working on establishing these political alliances, Charles V, the Holy Roman Emperor, invited Protestants to the Augsburg Diet to present their views so that he could make a verdict on the issue of faith. The Lutherans presented the Augsburg Confession. Under the leadership of Martin Bucer, the cities of Strasbourg, Constance, Memmingen, and Lindau produced the Tetrapolitan Confession. This document attempted to take a middle position between the Lutherans and Zwinglians.

It was too late for the Burgrecht cities to produce a confession of their own. Zwingli then produced his own private confession, Fidei ratio (Account of Faith) in which he explained his faith in twelve articles conforming to the articles of the Apostles' Creed. The tone was strongly anti-Catholic as well as anti-Lutheran. The Lutherans did not react officially, but criticised it privately. Zwingli's and Luther's old opponent, Johann Eck, counter-attacked with a publication, Refutation of the Articles Zwingli Submitted to the Emperor.

When Philip of Hesse formed the Schmalkaldic League at the end of 1530, the four cities of the Tetrapolitan Confession joined on the basis of a Lutheran interpretation of that confession. Given the flexibility of the league's entrance requirements, Zürich, Basel, and Bern also considered joining. However, Zwingli could not reconcile the Tetrapolitan Confession with his own beliefs and wrote a harsh refusal to Bucer and Capito. This offended Philip to the point where relations with the League were severed. The Burgrecht cities now had no external allies to help deal with internal Confederation religious conflicts.

The peace treaty of the First Kappel War did not define the right of unhindered preaching in the Catholic states. Zwingli interpreted this to mean that preaching should be permitted, but the Five States suppressed any attempts to reform. The Burgrecht cities considered different means of applying pressure to the Five States. Basel and Schaffhausen preferred quiet diplomacy while Zürich wanted armed conflict. Zwingli and Jud unequivocally advocated an attack on the Five States. Bern took a middle position which eventually prevailed. In May 1531, Zürich reluctantly agreed to impose a food blockade. It failed to have any effect and in October, Bern decided to withdraw the blockade. Zürich urged its continuation and the Burgrecht cities began to quarrel among themselves.

On 9 October 1531, in a surprise move, the Five States declared war on Zürich. Zürich's mobilisation was slow due to internal squabbling and, on 11 October, 3500 poorly deployed men encountered a Five States force nearly double their size near Kappel. Many pastors, including Zwingli, were among the soldiers. The battle lasted less than one hour and Zwingli was among the 500 casualties in the Zürich army.

Zwingli had considered himself first and foremost a soldier of Christ; second a defender of his country, the Confederation; and third a leader of his city, Zürich, where he had lived for the previous twelve years. Ironically, he died at the age of 47, not for Christ nor for the Confederation, but for Zürich.

In Tabletalk, Luther is recorded saying: "They say that Zwingli recently died thus; if his error had prevailed, we would have perished, and our church with us. It was a judgment of God. That was always a proud people. The others, the papists, will probably also be dealt with by our Lord God."

Erasmus wrote, "We are freed from great fear by the death of the two preachers, Zwingli and Oecolampadius, whose fate has wrought an incredible change in the mind of many. This is the wonderful hand of God on high." Oecolampadius had died on 24 November. Erasmus also wrote, "If Bellona had favoured them, it would have been all over with us."

Theology
According to Zwingli, the cornerstone of theology is the Bible. Zwingli appealed to scripture constantly in his writings. He placed its authority above other sources such as the ecumenical councils or the Church Fathers, although he did not hesitate to use other sources to support his arguments. The principles that guide Zwingli's interpretations are derived from his rationalist humanist education and his Reformed understanding of the Bible. He rejected literalist interpretations of a passage, such as those of the Anabaptists, and used synecdoche and analogies, methods he describes in A Friendly Exegesis (1527). Two analogies that he used quite effectively were between Baptism and circumcision and between the Eucharist and Passover. He also paid attention to the immediate context and attempted to understand the purpose behind it, comparing passages of scripture with each other.

Zwingli rejected the word sacrament in the popular usage of his time. For ordinary people, the word meant some kind of holy action of which there is inherent power to free the conscience from sin. For Zwingli, a sacrament was an initiatory ceremony or a pledge, pointing out that the word was derived from sacramentum meaning an oath. (However, the word is also translated "mystery".) In his early writings on baptism, he noted that baptism was an example of such a pledge. He challenged Catholics by accusing them of superstition when they ascribed the water of baptism a certain power to wash away sin. Later, in his conflict with the Anabaptists, he defended the practice of infant baptism, noting that there is no law forbidding the practice. He argued that baptism was a sign of a covenant with God, thereby replacing circumcision in the Old Testament.

Zwingli approached the eucharist in a similar manner to baptism. During the first Zürich disputation in 1523, he denied that an actual sacrifice occurred during the mass, arguing that Christ made the sacrifice only once and for all eternity. Hence, the eucharist was "a memorial of the sacrifice". Following this argument, he further developed his view, coming to the conclusion of the "signifies" interpretation for the words of the institution. He used various passages of scripture to argue against transubstantiation as well as Luther's views, the key text being John 6:63, "It is the Spirit who gives life, the flesh is of no avail". Zwingli's approach and interpretation of scripture to understand the meaning of the eucharist was one reason he could not reach a consensus with Luther.

The impact of Luther on Zwingli's theological development has long been a source of interest and discussion among Lutheran scholars, who seek to firmly establish Luther as the first Reformer. Zwingli himself asserted vigorously his independence of Luther and the most recent studies have lent credibility to this claim. Zwingli appears to have read Luther's books in search of confirmation from Luther for his own views. He agreed with the stand Luther took against the pope. Like Luther, Zwingli was also a student and admirer of Augustine.

In contrast to Luther, Zwingli adhered to official church theology on Judaism. However, as most Protestants and Catholics did at the time, he believed that the crucifixion of Christ led to the dispersal of Jews from Jerusalem. In contrast, Zwingli's creed was convinced that the papacy and its military power derived from Jewish influences. Together with John Calvin, he protracted Jewish influences in Christian churches and advocated the Principle of Sola Scriptura, in which the Old Testament and its subjects would remain a constant influence in future churches. He thereby opposed the anti-Semitic tendencies of Luther, and placed himself closer to Catholicism during the Reformation.

Music
Zwingli enjoyed music and could play several instruments, including the violin, harp, flute, dulcimer and hunting horn. He would sometimes amuse the children of his congregation on his lute and was so well known for his playing that his enemies mocked him as "the evangelical lute-player and fifer." Three of Zwingli's Lieder or hymns have been preserved: the Pestlied mentioned above, an adaptation of Psalm 65 (c. 1525), and the Kappeler Lied, which is believed to have been composed during the campaign of the first war of Kappel (1529). These songs were not meant to be sung during worship services and are not identified as hymns of the Reformation, though they were published in some 16th-century hymnals. Zwingli criticized the practice of priestly chanting and monastic choirs. The criticism dates from 1523 when he attacked certain worship practices. His arguments are detailed in the Conclusions of 1525, in which, Conclusions 44, 45 and 46 are concerned with musical practices under the rubric of "prayer". He associated music with images and vestments, all of which he felt diverted people's attention from true spiritual worship. It is not known what he thought of the musical practices in early Lutheran churches. Zwingli, however, eliminated instrumental music from worship in the church, stating that God had not commanded it in worship. The organist of the People's Church in Zürich is recorded as weeping upon seeing the great organ broken up. Although Zwingli did not express an opinion on congregational singing, he made no effort to encourage it. Nevertheless, scholars have found that Zwingli was supportive of a role for music in the church. Gottfried W. Locher writes, "The old assertion 'Zwingli was against church singing' holds good no longer ... Zwingli's polemic is concerned exclusively with the medieval Latin choral and priestly chanting and not with the hymns of evangelical congregations or choirs". Locher goes on to say that "Zwingli freely allowed vernacular psalm or choral singing. In addition, he even seems to have striven for lively, antiphonal, unison recitative". Locher then summarizes his comments on Zwingli's view of church music as follows: "The chief thought in his conception of worship was always 'conscious attendance and understanding'—'devotion', yet with the lively participation of all concerned".

Legacy
Zwingli was a humanist and a scholar with many devoted friends and disciples. He communicated as easily with the ordinary people of his congregation as with rulers such as Philip of Hesse. His reputation as a stern, stolid reformer is counterbalanced by the fact that he had an excellent sense of humour and used satiric fables, spoofing, and puns in his writings. He was more conscious of social obligations than was Luther, and he genuinely believed that the masses would accept a government guided by God's word. He tirelessly promoted assistance to the poor, who he believed should be cared for by a truly Christian community.

In December 1531 the Zürich council selected Heinrich Bullinger (1504–1575) as Zwingli's successor. Bullinger immediately removed any doubts about Zwingli's orthodoxy and defended him as a prophet and a martyr. During Bullinger's ascendancy, the confessional divisions of the Swiss Confederation stabilised. Bullinger rallied the reformed cities and cantons and helped them to recover from the defeat at Kappel. Zwingli had instituted fundamental reforms; Bullinger consolidated and refined them. Scholars have found it difficult to assess Zwingli's impact on history, for several reasons. There is no consensus on the definition of "Zwinglianism"; by any definition, Zwinglianism evolved under his successor, Heinrich Bullinger; and research into Zwingli's influence on Bullinger and John Calvin remains rudimentary. Bullinger adopted most of Zwingli's points of doctrine. Like Zwingli, he summarised his theology several times, the best-known example being the Second Helvetic Confession of 1566. Meanwhile, Calvin had taken over the Reformation in Geneva. Calvin differed with Zwingli on the eucharist and criticised him for regarding it as simply a metaphorical event. In 1549, however, Bullinger and Calvin succeeded in overcoming the differences in doctrine and produced the Consensus Tigurinus (Zürich Consensus). They declared that the eucharist was not just symbolic of the meal, but they also rejected the Lutheran position that the body and blood of Christ is in union with the elements. With this rapprochement, Calvin established his role in the Swiss Reformed Churches and eventually in the wider world.

The Swiss Reformed churches count Zwingli as their founder, as does the Reformed Church in the United States (both its present liberal and conservative descendant denominations, with the former taking a historical-critical interpretation of Zwinglian theology and using it as a basis for ecumenism, and the latter interpreting his teachings as binding upon consciences and, in effect, as inerrant as Scripture itself), according to 19th-century RCUS historian J.I. Good. Scholars speculate as to why Zwinglianism has not diffused more widely, even though Zwingli's theology is considered the first expression of Reformed theology. Although his name is not widely recognised, Zwingli's legacy lives on in the basic confessions of the Reformed churches of today. He is often called, after Martin Luther and John Calvin, the "Third Man of the Reformation".

In 2019 the Swiss director Stefan Haupt released a Swiss-German film on the career of the reformer: Zwingli. It was filmed in Swiss German with French and English subtitles available.

2019 began the 500th anniversary of the Swiss Reformation with a conference at John Calvin University, and renewed interest in revisiting the life and impact of Zwingli. Examples include the film Zwingli, Bruce Gordon's book, Zwingli: God's Armed Prophet and an article by Thomas Quinn Marabello, "The 500th Anniversary of the Swiss Reformation: How Zwingli changed and continues to impact Switzerland today".

List of works
Zwingli's collected works are expected to fill 21 volumes. A collection of selected works was published in 1995 by the Zwingliverein in collaboration with the Theologischer Verlag Zürich. This four-volume collection contains the following works:
 * Volume 1: 1995, 512 pages, ISBN 3-290-10974-7
 * Pestlied (1519/20) "The Plague Song"
 * Die freie Wahl der Speisen (1522) "Choice and Liberty regarding Food"
 * Eine göttliche Ermahnung der Schwyzer (1522) "A Solemn Exhortation [to the people of Schwyz]"
 * Die Klarheit und Gewissheit des Wortes Gottes (1522) "The Clarity and Certainty of the Word of God"
 * Göttliche und menschliche Gerechtigkeit (1523) "Divine and Human Righteousness"
 * Wie Jugendliche aus gutem Haus zu erziehen sind (1523) "How to educate adolescents from a good home"
 * Der Hirt (1524) "The Shepherd"
 * Eine freundschaftliche und ernste Ermahnung der Eidgenossen (1524) "Zwingli's Letter to the Federation"
 * Wer Ursache zum Aufruhr gibt (1524) "Those Who Give Cause for Tumult"
 * Volume 2: 1995, 556 pages, ISBN 3-290-10975-5
 * Auslegung und Begründung der Thesen oder Artikel (1523) "Interpretation and justification of the theses or articles"
 * Volume 3: 1995, 519 pages, ISBN 3-290-10976-3
 * Empfehlung zur Vorbereitung auf einen möglichen Krieg (1524) "Plan for a Campaign"
 * Kommentar über die wahre und die falsche Religion (1525) "Commentary on True and False Religion"
 * Volume 4: 1995, 512 pages, ISBN 3-290-10977-1
 * Antwort auf die Predigt Luthers gegen die Schwärmer (1527) "A Refutation of Luther's sermon against vain enthusiasm"
 * Die beiden Berner Predigten (1528) "The Berne sermons"
 * Rechenschaft über den Glauben (1530) "An Exposition of the Faith"
 * Die Vorsehung (1530) "Providence"
 * Erklärung des christlichen Glaubens (1531) "Explanation of the Christian faith"

The complete 21-volume edition is being undertaken by the Zwingliverein in collaboration with the Institut für schweizerische Reformationsgeschichte, and is projected to be organised as follows:
 * vols. I–VI Werke: Zwingli's theological and political writings, essays, sermons etc., in chronological order. This section was completed in 1991.
 * vols. VII–XI Briefe: Letters
 * vol. XII Randglossen: Zwingli's glosses in the margin of books
 * vols XIII ff. Exegetische Schriften: Zwingli's exegetical notes on the Bible.

Vols. XIII and XIV have been published, vols. XV and XVI are under preparation. Vols. XVII to XXI are planned to cover the New Testament.

Older German / Latin editions available online include:
 * Huldreich Zwinglis sämtliche Werke, vol. 1, Corpus Reformatorum vol. 88, ed. Emil Egli. Berlin: Schwetschke, 1905.
 * Analecta Reformatoria: Dokumente und Abhandlungen zur Geschichte Zwinglis und seiner Zeit, vol. 1, ed. Emil Egli. Zürich: Züricher and Furrer, 1899.
 * Huldreich Zwingli's Werke, ed. Melchior Schuler and Johannes Schulthess, 1824ff.: vol. I; vol. II;vol. III; vol. IV; vol. V; vol. VI, 1; vol. VI, 2; vol. VII; vol. VIII.
 * Der evangelische Glaube nach den Hauptschriften der Reformatoren, ed. Paul Wernle. Tübingen: Mohr, 1918.
 * Von Freiheit der Speisen, eine Reformationsschrift, 1522, ed. Otto Walther. Halle: Niemeyer, 1900.

See also the following English translations of selected works by Zwingli:
 * The Christian Education of Youth. Collegeville: Thompson Bros., 1899.
 * Selected Works of Huldreich Zwingli (1484–1531). Philadelphia: University of Pennsylvania, 1901.
 * The Latin Works and the Correspondence of Huldreich Zwingli, Together with Selections from his German Works.
 * Vol. 1, 1510–1522, New York: G.P. Putnam and Sons, 1912.
 * Vol. 2, Philadelphia: Heidelberg Press, 1912.
 * Vol. 3, Philadelphia: Heidelberg Press, 1912.

title: Huldrych Zwingli


text:
Homeschooling

Homeschooling or home schooling, also known as home education or elective home education (EHE), is the education of school-aged children at home or a variety of places other than a school. Usually conducted by a parent, tutor, or online teacher, many homeschool families use less formal, more personalized and individualized methods of learning that are not always found in schools. The actual practice of homeschooling varies considerably. The spectrum ranges from highly structured forms based on traditional school lessons to more open, free forms such as unschooling, which is a lesson- and curriculum-free implementation of homeschooling. Some families who initially attended a school go through a deschool phase to break away from school habits and prepare for homeschooling. While "homeschooling" is the term commonly used in North America, "home education" is primarily used in Europe and many Commonwealth countries. Homeschooling should not be confused with distance education, which generally refers to the arrangement where the student is educated by and conforms to the requirements of an online school, rather than being educated independently and unrestrictedly by their parents or by themselves.

Before the introduction of compulsory school attendance laws, most childhood education was done by families and local communities. By the early 19th century, attending a school became the most common means of education in the developed world. In the mid to late 20th century, more people began questioning the practice of school learning, which again led to an increase in the number of homeschoolers, especially in the Americas and some European countries. In the 21st century, homeschooling is a relatively widespread form of education and a legal alternative to public and private schools in many countries, which many people believe is due to the rise of the Internet, which enables people to obtain information very quickly. The regulation and legality of homeschooling varies by jurisdiction.

There are many different reasons for homeschooling, ranging from personal interests to dissatisfaction with the public school system. Homeschooling is also an option for families living in remote rural areas, those temporarily abroad, those who travel frequently and therefore face the physical impossibility or difficulty of getting their children into school, and those who want to spend more time with their children. Health reasons and special needs can also play a role in why children cannot attend a school regularly and are at least partially homeschooled.

Critics of homeschooling argue that children may lack adequate socialization and therefore have poorer social skills. Some are also concerned that parents may be unqualified to guide and advise their children. Critics also say that a child might not encounter people of other cultures, worldviews, and socioeconomic groups if they are not enrolled in a school. Therefore, these critics believe that homeschooling cannot guarantee a comprehensive and neutral education if educational standards are not prescribed. Studies on homeschooled students typically rely convenience sampling, which may disproportionately sample the highest-achieving homeschoolers. Researchers have identified a need for more representative samples in studying homeschooling.

Terminology
While "homeschooling" is the term commonly used in the United States and other nations in North America, "home education" is primarily used in the United Kingdom, elsewhere in Europe and many Commonwealth countries.

Early history
For most of history and in different cultures, homeschooling was a common practice by family members and local communities. Enlisting professional tutors was an option available only to the wealthy. Homeschooling declined in the 19th and 20th centuries with the enactment of compulsory school attendance laws. However, it continued to be practised in isolated communities. Homeschooling began a resurgence in the 1960s and 1970s with educational reformists dissatisfied with industrialized education.

Home education and apprenticeship continued to remain the main form of education until the 1830s. However, in the 18th century, the majority of people in Europe lacked formal education. Since the early 19th century, formal classroom schooling became the most common means of schooling throughout the developed countries.

United States
In the 1960s, Rousas John Rushdoony began to advocate homeschooling, which he saw as a way to combat the secular nature of the public school system in the United States. He vigorously attacked progressive school reformers such as Horace Mann and John Dewey, and argued for the dismantling of the state's influence in education in three works: Intellectual Schizophrenia, The Messianic Character of American Education, and The Philosophy of the Christian Curriculum. Rushdoony was frequently called as an expert witness by the Home School Legal Defense Association (HSLDA) in court cases. He frequently advocated the use of private schools. The HSLDA influenced changes to the legal status of homeschooling across the United States.

Conservative Christian parents were increasingly dissatisfied with the public school system and were the main demographic that organized to promote home education in the United States. This movement embraced research conducted by other religious parents that advocated for homeschooling such as Raymond and Dorothy Moore. Another influential figure associated with the rise of the homeschooling movement was John Holt. Holt believed that informal education was better than compulsory education and expressed these views in his books How Children Fail and How Children Learn. Holt advocated for unschooling, where children learn without any formalized curriculum or expectations.

Recent
Schools were widely shut down during the early part of the COVID-19 pandemic, with schools instead using distance education. This is not considered homeschooling, however, since their education was directed by public schools.

Motivations

There are a multitude of sometimes complex reasons why parents and children choose to homeschool, some of which overlap with those for unschooling and may be very different depending on the country and (current) situation of parents and children.

Parents commonly cite two main motivations for homeschooling their children: dissatisfaction with the local schools and the interest in increased involvement with their children's learning and development. Parental dissatisfaction with available schools typically includes concerns about the school environment, the quality of academic instruction, the curriculum, bullying, racism and lack of faith in the school's ability to cater to their children's special needs. Some parents homeschool in order to have greater control over what and how their children are taught, to cater more adequately to an individual child's aptitudes and abilities, to provide instruction from a specific religious or and moral position, and to take advantage of the efficiency of one-to-one instruction and thus allow the child to spend more time on childhood activities, socializing, and non-academic learning.

Some African-American families choose to homeschool as a way of increasing their children's understanding of African-American history – such as the Jim Crow laws that resulted in African Americans being prevented from reading and writing – and to limit the harm caused by the unintentional and sometimes subtle systemic racism that affects most American schools.

Some parents have objections to the secular nature of public schools and homeschool in order to give their children a religious education. Use of a religious curriculum is common among these families.

Some parents are of the opinion that certain temperaments are promoted in school, while others are inhibited which may also be a reason to homeschool their children.

Another argument for homeschooling children may be the protection against physical and emotional violence, bullying, exclusion, drugs, stress, sexualization, social pressures, excessive performance thoughts, socialization groups or role models with negative impact and degrading treatment in school.

Some children may also prefer to or can learn more efficiently at home, for example, because they are not distracted or slowed down by school matters and can, for example, spend several hours dealing with the same topic undisturbed. There are studies that show that homeschooled children are more likely to graduate and perform better at university.

Homeschooling may also be a factor in the choice of parenting style. Homeschooling can be a matter of consistency for families living in isolated rural locations, for those temporarily abroad, and for those who travel frequently. Many young athletes, actors, and musicians are taught at home to accommodate their training and practice schedules more conveniently. Homeschooling can be about mentorship and apprenticeship, in which a tutor or teacher is with the child for many years and becomes more intimately acquainted with the child. Many parents also homeschool their children and return their child into the school system later on, for example because they think that their child is too young or not yet ready to start school.

Some children also have health issues and therefore cannot attend a school regularly and are at least partially homeschooled or take distance education instead.

COVID-19 has reinforced some parents' minds about homeschooling. The fact that parents realized remote learning was possible thanks to new technologies means that they have additional options to consider should their child face problems of any kind at school.

Teaching methods, forms and philosophies
Homeschooling is usually conducted by a parent, tutor, or an online teacher, but the concrete practice can be very different. The spectrum ranges from highly structured forms based on traditional school lessons to more open, free forms like unschooling, which is a curriculum-free implementation of homeschooling that involves teaching children based on their interests.

Many homeschool families use a wide variety of methods and materials and less formal educational methods, which represent a variety of educational philosophies and paradigms. Some of the methods or learning environments used include classical education (including Trivium, Quadrivium), Charlotte Mason education, Montessori method, theory of multiple intelligences, unschooling, Waldorf education, school-at-home (curriculum choices from both secular and religious publishers), A Thomas Jefferson Education, unit studies, curriculum made up from private or small publishers, apprenticeship, hands-on-learning, distance learning (both online and correspondence), dual enrollment in local schools or colleges, and curriculum provided by local schools and many others. Some of these approaches are used in private and public schools. Educational research and studies support the use of some of these methods. Unschooling, natural learning, Charlotte Mason Education, Montessori, Waldorf, apprenticeship, hands-on-learning, unit studies are supported to varying degrees by research by constructivist learning theories and situated cognition theories. Elements of these theories may be found in the other methods as well.

A student's education may be customized to support his or her learning level, style, and interests. It is not uncommon for a student to experience more than one approach as the family discovers what works best for their student. Many families use an eclectic approach, picking and choosing from various suppliers. For sources of curricula and books, a study found that 78 percent utilized "a public library"; 77 percent used "a homeschooling catalogue, publisher, or individual specialist"; 68 percent used "retail bookstore or another store"; 60 percent used "an education publisher that was not affiliated with homeschooling." "Approximately half" used curriculum from "a homeschooling organization", 37 percent from a "church, synagogue or other religious institution" and 23 percent from "their local public school or district." In 2003, 41 percent utilized some sort of distance learning, approximately 20 percent by "television, video or radio"; 19 percent via "The Internet, e-mail, or the World Wide Web"; and 15 percent taking a "correspondence course by mail designed specifically for homeschoolers."

Individual governmental units, e.g. states and local districts, vary in official curriculum and attendance requirements.

Informal learning
As a subset of homeschooling, informal learning happens outside of the classroom but has no traditional boundaries of education. Informal learning is an everyday form of learning through participation and creation, in contrast with the traditional view of teacher-centered learning. The term is often combined with non-formal learning and self-directed learning. Informal learning differs from traditional learning since there are no expected objectives or outcomes. From the learner's standpoint, the knowledge that they receive is not intentional. Topics such as planting a garden, baking a cake or even talking to a technician at work about the installation of new software can be considered informal learning. The individual is completing a task with different intentions but ends up learning skills in the process. Children watching their tomato plants grow will not generate questions about photosynthesis but they will learn that their plants are growing with water and sunlight. This leads them to have a base understanding of complex scientific concepts without any background studying. The recent trend of homeschooling becoming less stigmatized has been in connection with the traditional waning of the idea that the state needs to be in primary and ultimate control over the education and upbringing of all children to create future adult citizens. This breeds an ever-growing importance on the ideas and concepts that children learn outside of the traditional classroom setting, including informal learning.

Depending on the part of the world, informal learning can take on many different identities and has differing cultural importances. Many ways of organizing homeschooling draw on apprenticeship qualities and on non-western cultures. In some South American indigenous cultures, such as the Chillihuani community in Peru, children learn irrigation and farming technique through play, advancing them not only in their own village and society but also in their knowledge of realistic techniques that they will need to survive. In Western culture, children use informal learning in two main ways. The first as talked about is through hands-on experience with new material. The second is asking questions to someone who has more experience than they have (i.e. parents, elders). Children's inquisitive nature is their way of cementing the ideas they have learned through exposure to informal learning. It is a more casual way of learning than traditional learning and serves the purpose of taking in information any which way they can.

Structured versus unstructured
All other approaches to homeschooling are subsumed under two basic categories: structured and unstructured homeschooling. Structured homeschooling includes any method or style of home education that follows a basic curriculum with articulated goals and outcomes. This style attempts to imitate the structure of the traditional school setting while personalizing the curriculum. Unstructured homeschooling is any form of home education where parents do not construct a curriculum at all. Unschooling, as it is known, attempts to teach through the child's daily experiences and focuses more on self-directed learning by the child, free of textbooks, teachers, and any formal assessment of success or failure.

Unit studies
In a unit study approach, multiple subjects such as math, science, history, art, and geography, are studied in relation to a single topic. Unit studies are useful for teaching multiple grades simultaneously as the difficulty level can be adjusted for each student. An extended form of unit studies, Integrated Thematic Instruction utilizes one central theme integrated throughout the curriculum so that students finish a school year with a deep understanding of a certain broad subject or idea.

All-in-one curricula
All-in-one homeschooling curricula (variously known as school-at-home, the traditional approach, or school-in-a-box) are instructional methods of teaching in which the curriculum and homework of the student are similar or identical to those used in a public or private school. Purchased as a grade-level package or separately by subject, the package may contain all of the needed books, materials, tests, answer keys, and extensive teacher guides. These materials cover the same subject areas as public schools, allowing for an easy transition into the school system. These are among the most expensive options for homeschooling, but they require minimal preparation and are easy to use. Some localities provide the same materials used at local schools to homeschoolers. The purchase of a complete curriculum and their teaching/grading service from an accredited distance learning curriculum provider may allow students to obtain an accredited high school diploma.

Unschooling and natural learning
Natural learning refers to a type of learning-on-demand where children pursue knowledge based on their interests and parents take an active part in facilitating activities and experiences conducive to learning but do not rely heavily on textbooks or spend much time "teaching", looking instead for "learning moments" throughout their daily activities. Parents see their role as that of affirming through positive feedback and modeling the necessary skills, and the child's role as being responsible for asking and learning.

The term unschooling as coined by John Holt describes an approach in which parents do not authoritatively direct the child's education, but interact with the child following the child's own interests, leaving them free to explore and learn as their interests lead.

Another prominent proponent of unschooling is John Taylor Gatto, author of Dumbing Us Down, The Exhausted School, A Different Kind of Teacher, and Weapons of Mass Instruction. Gatto argues that public education is the primary tool of "state-controlled consciousness" and serves as a prime illustration of the total institution — a social system which impels obedience to the state and quells free-thinking or dissent.

Autonomous learning
Autonomous learning is a school of education which sees learners as individuals who can and should be autonomous; i.e., be responsible for their own learning climate.

Autonomous education helps students develop their self-consciousness, vision, practicality, and freedom of discussion. These attributes serve to aid the student in his/her independent learning. However, a student must not start their autonomous learning completely on their own. It is said that first having interaction with someone who has more knowledge in a subject will speed up the student's learning and allow them to learn more independently.

Some degree of autonomous learning is popular with those who home educate their children. In true autonomous learning, the child usually gets to decide what projects they wish to tackle or what interests to pursue. In-home education, this can be instead of or in addition to regular subjects like doing math or English.

Hybrid homeschooling
Hybrid homeschooling or flex-school is a form of homeschooling in which children split their time between homeschool and a more traditional schooling environment like a school. The number of students who participated in hybrid homeschooling increased during the COVID-19 pandemic.

A commonly cited reason for choosing this model is that parents are not sure whether they can provide their children a comprehensive and neutral education at home or cannot devote themselves to homeschooling full-time due to time constraints or excessive stress. Some families also want their children to socialize with other children and find that schools are better suited for this purpose because social exchange does not only take place occasionally, but is an everyday experience there.

Homeschool cooperatives
A homeschool cooperative is a cooperative of families who homeschool their children. It provides an opportunity for children to learn from other parents who are more specialized in certain areas or subjects. Co-ops also provide social interaction. They may take lessons together or go on field trips. Some co-ops also offer events such as prom and graduation for homeschoolers.

Homeschoolers are beginning to utilize Web 2.0 as a way to simulate homeschool cooperatives online. With social networks, homeschoolers can chat, discuss threads in forums, share information and tips, and even participate in online classes via learning management systems similar to those used by colleges.

General
As of 2022, virtually all research on homeschooling used convenience sampling, with selection bias as a concern. Conclusions of research on homeschooling can be biased if only the highest-achieving homeschoolers are studied. Other common methodological problems were identified that need to be addressed in future research, such as controlling for confounding factors such as socioeconomic status and parental involvement, incorporating data from other adults and from homeschooled children themselves and their peers rather than just the parents, and taking into account the timing and duration of homeschooling due to the fact that many families discontinue homeschooling after one or a few years.

With the studies available, a review that year found it was too soon to offer firm conclusions because of these issues, but did not find systematic evidence of poor educational or social outcomes.

Academic
According to the Home School Legal Defense Association (HSLDA) in 2004, "Many studies over the last few years have established the academic excellence of homeschooled children." Home Schooling Achievement, a compilation of studies published by the HSLDA, supported the academic integrity of homeschooling. This booklet summarized a 1997 study by Ray and the 1999 Rudner study. The Rudner study noted two limitations of its own research: it is not necessarily representative of all homeschoolers and it is not a comparison with other schooling methods. Among the homeschooled students who took the tests, the average homeschooled student outperformed his public school peers by 30 to 37 percentile points across all subjects. The study also indicates that public school performance gaps between minorities and genders were virtually non-existent among the homeschooled students who took the tests.

A survey of 11,739 homeschooled students conducted in 2008 found that, on average, the homeschooled students scored 37 percentile points above public school students on standardized achievement tests. This is consistent with the 1999 Rudner study. However, Rudner said that these same students in public school may have scored just as well because of the dedicated parents they had. The Ray study also found that homeschooled students who had a certified teacher as a parent scored one percentile lower than homeschooled students who did not have a certified teacher as a parent. Another nationwide descriptive study conducted by Ray contained students ranging from ages 5–18 and he found that homeschoolers scored in at least the 80th percentile on their tests.

In 2011, a quasi-experimental study was conducted that included homeschooled and traditional public students between the ages of 5 and 10. It was discovered that the majority of the homeschooled children achieved higher standardized scores compared to their counterparts. However, Martin-Chang also found that unschooling children ages 5–10 scored significantly below traditionally educated children, while academically oriented homeschooled children scored from one half grade level above to 4.5 grade levels above traditionally schooled children on standardized tests (n=37 homeschooled children matched with children from the same socioeconomic and educational background).

Studies have also examined the impact of homeschooling on students' GPAs. Cogan (2010) found that homeschooled students had higher high school GPAs (3.74) and transfer GPAs (3.65) than conventional students. Snyder (2013) provided corroborating evidence that homeschoolers were outperforming their peers in the areas of standardized tests and overall GPAs. Looking beyond high school, a study by the 1990 National Home Education Research Institute (as cited by Wichers, 2001) found that at least 33% of homeschooled students attended a four-year college, and 17% attended a two-year college. This same study examined the students after one year, finding that 17% pursued higher education.

On average, studies suggest homeschoolers score at or above the national average on standardized tests. Homeschool students have been accepted into many Ivy League universities.

Homeschooled children may receive more individualized attention than students enrolled in traditional public schools. A 2011 study suggests that a structured environment could play a key role in homeschooler academic achievement. This means that parents were highly involved in their child's education and they were creating clear educational goals. In addition, these students were being offered organized lesson plans which are either self-made or purchased.

A study conducted by Ray in 2010 indicates that the higher the level of parents' income, the more likely the homeschooled child is able to achieve academic success.

Some homeschoolers averaged higher scores on these college entrance tests in South Carolina. Other scores (1999 data) showed mixed results, for example showing higher levels for homeschoolers in English (homeschooled 23.4 vs national average 20.5) and reading (homeschooled 24.4 vs national average 21.4) on the ACT, but mixed scores in math (homeschooled 20.4 vs national average 20.7 on the ACT as opposed homeschooled 535 vs national average 511 on the 1999 SAT math).

According to a study done on the homeschool movement, homeschoolers often achieve academic success and admission into elite universities. According to the National Home Education Research Institute president, Brian Ray, socialization is not a problem for homeschooling children, many of whom are involved in community sports, volunteer activities, book groups, or homeschool co-ops.

In the UK, the government has noted that no figures are available on educational attainment for children educated at home: "This means no assessment can be made of the impact on educational attainment of being home schooled". There is some evidence from 2009 that home-educated children in the UK are more likely to be NEET, Not in Employment, Education or Training, at age 16 to 18.

Social
Using the Piers-Harris Children's Self-Concept Scale, John Taylor later found that, "while half of the conventionally schooled children scored at or below the 50th percentile (in self-concept), only 10.3% of the home-schooling children did so." He further stated that "the self-concept of home-schooling children is significantly higher statistically than that of children attending conventional school. This has implications in the areas of academic achievement and socialization which have been found to parallel self-concept. Regarding socialization, Taylor's results would mean that very few home-schooling children are socially deprived. He states that critics who speak out against homeschooling on the basis of social deprivation are actually addressing an area which favours homeschoolers.

Richard G. Medlin, Ph.D.'s research found that homeschooled children have better social skills than children attending traditional schools.

Other
Homeschooled youth are less likely to use and abuse illicit substances and are more likely to disapprove of using alcohol and marijuana. There are also studies according to which homeschooled children are less likely to be sexually abused than children in public schools.

Criticism
Critics of homeschooling point to methodological problems with the studies on homeschooling that have been done, which are typically based on non-representative convenience samples.

Some organizations of teachers and school districts resist homeschooling. The National Education Association, a United States teachers' union and professional association, has asserted that teachers should be licensed and that state-approved curricula should be used. Elizabeth Bartholet, a Harvard professor of law and faculty director of the Law School's Child Advocacy Program, recommended a ban on home education in 2019, calling it a risky practice.

Gallup polls of American voters showed a significant change in attitude from 1985 to 2001, with respondents going from 73% opposed to homeschooling to 54% opposed. In 1988, when asked whether parents should have a right to choose homeschooling, 53 percent thought that they should, as revealed by another poll.

There is also concern that homeschooling reduces a child's exposure to mandated reporters such as teachers, making children more susceptible to sustained, unreported abuse. While there is not enough data to determine exact rates of abuse in homeschooling there is, however, strong evidence to suggest that parents who engage in maltreatment and educational neglect are more likely to use homeschooling as a guise.

The vast majority of homeschoolers are doing so for religious reasons. They are primarily concerned with producing "virtuous" adults, rather than "educated" adults. Political scientist Rob Reich speculated in The Civic Perils of Homeschooling (2002) that homeschooling could threaten to "insulate students from exposure to diverse ideas and people."

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Homeschooling


text:
Heteroatom

In chemistry, a heteroatom is, strictly, any atom that is not carbon or hydrogen.

Organic chemistry
In practice, the term is usually used more specifically to indicate that non-carbon atoms have replaced carbon in the backbone of the molecular structure. Typical heteroatoms are nitrogen (N), oxygen (O), sulfur (S), phosphorus (P), chlorine (Cl), bromine (Br), and iodine (I), as well as the metals lithium (Li) and magnesium (Mg).

Proteins
It can also be used with highly specific meanings in specialised contexts. In the description of protein structure, in particular in the Protein Data Bank file format, a heteroatom record (HETATM) describes an atom as belonging to a small molecule cofactor rather than being part of a biopolymer chain.

Zeolites
In the context of zeolites, the term heteroatom refers to partial isomorphous substitution of the typical framework atoms (silicon, aluminium, and phosphorus) by other elements such as beryllium, vanadium, and chromium. The goal is usually to adjust properties of the material (e.g., Lewis acidity) to optimize the material for a certain application (e.g., catalysis).

title: Heteroatom


text:
Half-life

Half-life (symbol $t½$) is the time required for a quantity (of substance) to reduce to half of its initial value. The term is commonly used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay or how long stable atoms survive. The term is also used more generally to characterize any type of exponential (or, rarely, non-exponential) decay. For example, the medical sciences refer to the biological half-life of drugs and other chemicals in the human body. The converse of half-life (in exponential growth) is doubling time.

The original term, half-life period, dating to Ernest Rutherford's discovery of the principle in 1907, was shortened to half-life in the early 1950s. Rutherford applied the principle of a radioactive element's half-life in studies of age determination of rocks by measuring the decay period of radium to lead-206.

Half-life is constant over the lifetime of an exponentially decaying quantity, and it is a characteristic unit for the exponential decay equation. The accompanying table shows the reduction of a quantity as a function of the number of half-lives elapsed.

Probabilistic nature

A half-life often describes the decay of discrete entities, such as radioactive atoms. In that case, it does not work to use the definition that states "half-life is the time required for exactly half of the entities to decay". For example, if there is just one radioactive atom, and its half-life is one second, there will not be "half of an atom" left after one second.

Instead, the half-life is defined in terms of probability: "Half-life is the time required for exactly half of the entities to decay on average". In other words, the probability of a radioactive atom decaying within its half-life is 50%.

For example, the accompanying image is a simulation of many identical atoms undergoing radioactive decay. Note that after one half-life there are not exactly one-half of the atoms remaining, only approximately, because of the random variation in the process. Nevertheless, when there are many identical atoms decaying (right boxes), the law of large numbers suggests that it is a very good approximation to say that half of the atoms remain after one half-life.

Various simple exercises can demonstrate probabilistic decay, for example involving flipping coins or running a statistical computer program.

Formulas for half-life in exponential decay
An exponential decay can be described by any of the following four equivalent formulas: $$\begin{align} N(t) &= N_0 \left(\frac {1}{2}\right)^{\frac{t}{t_{1/2}}} \\ N(t) &= N_0 2^{-\frac{t}{t_{1/2}}} \\ N(t) &= N_0 e^{-\frac{t}{\tau}} \\ N(t) &= N_0 e^{-\lambda t} \end{align}$$ where
 * $N0$ is the initial quantity of the substance that will decay (this quantity may be measured in grams, moles, number of atoms, etc.),
 * $N(t)$ is the quantity that still remains and has not yet decayed after a time $1/1$,
 * $t½$ is the half-life of the decaying quantity,
 * $1/8$ is a positive number called the mean lifetime of the decaying quantity,
 * $1/16$ is a positive number called the decay constant of the decaying quantity.

The three parameters $t½$, $1/32$, and $1/64$ are directly related in the following way:$$t_{1/2} = \frac{\ln (2)}{\lambda} = \tau \ln(2)$$where $ln(2)$ is the natural logarithm of 2 (approximately 0.693).

Half-life and reaction orders
In chemical kinetics, the value of the half-life depends on the reaction order:

Zero order kinetics
The rate of this kind of reaction does not depend on the substrate concentration, $[A]$. Thus the concentration decreases linearly.

 * The integrated rate law of zero order kinetics is:

In order to find the half-life, we have to replace the concentration value for the initial concentration divided by 2: and isolate the time:This $t½$ formula indicates that the half-life for a zero order reaction depends on the initial concentration and the rate constant.

First order kinetics
In first order reactions, the rate of reaction will be proportional to the concentration of the reactant. Thus the concentration will decrease exponentially. as time progresses until it reaches zero, and the half-life will be constant, independent of concentration.

The time $t½$ for $[A]$ to decrease from $[A]0$ to $1⁄2[A]0$ in a first-order reaction is given by the following equation:It can be solved forFor a first-order reaction, the half-life of a reactant is independent of its initial concentration. Therefore, if the concentration of $A$ at some arbitrary stage of the reaction is $[A]$, then it will have fallen to $1⁄2[A]$ after a further interval of $1/128$ Hence, the half-life of a first order reaction is given as the following: $$t_{1/2} = \frac{\ln 2}{k}$$The half-life of a first order reaction is independent of its initial concentration and depends solely on the reaction rate constant, $n$.

Second order kinetics
In second order reactions, the rate of reaction is proportional to the square of the concentration. By integrating this rate, it can be shown that the concentration $[A]$ of the reactant decreases following this formula:

We replace $[A]$ for $1⁄2

[A]

0$ in order to calculate the half-life of the reactant $A$ and isolate the time of the half-life ($t½$):This shows that the half-life of second order reactions depends on the initial concentration and rate constant.

Decay by two or more processes
Some quantities decay by two exponential-decay processes simultaneously. In this case, the actual half-life $T½$ can be related to the half-lives $t1$ and $t2$ that the quantity would have if each of the decay processes acted in isolation: $$\frac{1}{T_{1/2}} = \frac{1}{t_1} + \frac{1}{t_2}$$

For three or more processes, the analogous formula is: $$\frac{1}{T_{1/2}} = \frac{1}{t_1} + \frac{1}{t_2} + \frac{1}{t_3} + \cdots$$ For a proof of these formulas, see Exponential decay § Decay by two or more processes.

Examples
There is a half-life describing any exponential-decay process. For example:
 * As noted above, in radioactive decay the half-life is the length of time after which there is a 50% chance that an atom will have undergone nuclear decay. It varies depending on the atom type and isotope, and is usually determined experimentally. See List of nuclides.
 * The current flowing through an RC circuit or RL circuit decays with a half-life of $ln(2)RC$ or $ln(2)L/R$, respectively. For this example the term half time tends to be used rather than "half-life", but they mean the same thing.
 * In a chemical reaction, the half-life of a species is the time it takes for the concentration of that substance to fall to half of its initial value. In a first-order reaction the half-life of the reactant is $ln(2)/λ$, where $1/2^{n}$ (also denoted as $100/2^{n}$) is the reaction rate constant.

In non-exponential decay
The term "half-life" is almost exclusively used for decay processes that are exponential (such as radioactive decay or the other examples above), or approximately exponential (such as biological half-life discussed below). In a decay process that is not even close to exponential, the half-life will change dramatically while the decay is happening. In this situation it is generally uncommon to talk about half-life in the first place, but sometimes people will describe the decay in terms of its "first half-life", "second half-life", etc., where the first half-life is defined as the time required for decay from the initial value to 50%, the second half-life is from 50% to 25%, and so on.

In biology and pharmacology
A biological half-life or elimination half-life is the time it takes for a substance (drug, radioactive nuclide, or other) to lose one-half of its pharmacologic, physiologic, or radiological activity. In a medical context, the half-life may also describe the time that it takes for the concentration of a substance in blood plasma to reach one-half of its steady-state value (the "plasma half-life").

The relationship between the biological and plasma half-lives of a substance can be complex, due to factors including accumulation in tissues, active metabolites, and receptor interactions.

While a radioactive isotope decays almost perfectly according to so-called "first order kinetics" where the rate constant is a fixed number, the elimination of a substance from a living organism usually follows more complex chemical kinetics.

For example, the biological half-life of water in a human being is about 9 to 10 days, though this can be altered by behavior and other conditions. The biological half-life of caesium in human beings is between one and four months.

The concept of a half-life has also been utilized for pesticides in plants, and certain authors maintain that pesticide risk and impact assessment models rely on and are sensitive to information describing dissipation from plants.

In epidemiology, the concept of half-life can refer to the length of time for the number of incident cases in a disease outbreak to drop by half, particularly if the dynamics of the outbreak can be modeled exponentially.

title: Half-life