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Bead

A bead is a small, decorative object that is formed in a variety of shapes and sizes of a material such as stone, bone, shell, glass, plastic, wood, or pearl and with a small hole for threading or stringing. Beads range in size from under 1 millimeter (0.039 in) to over 1 centimeter (0.39 in) in diameter.

Beads represent some of the earliest forms of jewellery, with a pair of beads made from Nassarius sea snail shells dating to approximately 100,000 years ago thought to be the earliest known example.[1][2] Beadwork is the art or craft of making things with beads. Beads can be woven together with specialized thread, strung onto thread or soft, flexible wire, or adhered to a surface (e.g. fabric, clay).

Types of beads
Beads can be divided into several types of overlapping categories based on different criteria such as the materials from which they are made, the process used in their manufacturing, the place or period of origin, the patterns on their surface, or their general shape. In some cases, such as millefiori and cloisonné beads, multiple categories may overlap in an interdependent fashion.

Components
Beads can be made of many different materials. The earliest beads were made of a variety of natural materials which, after they were gathered, could be readily drilled and shaped. As humans became capable of obtaining and working with more difficult materials, those materials were added to the range of available substances.

Beads were a part of different cultures, each made with different materials throughout history and using beads to form something handmade. Beads came in different colors, shapes, and forms, what materials were used, and whether there was a meaning or meaning behind the beads.

In modern manufacturing, the most common bead materials are wood, plastic, glass, metal, and stone.

Natural materials
Beads are still made from many naturally occurring materials, both organic (i.e., of animal- or plant-based origin) and inorganic (purely mineral origin). However, some of these materials now routinely undergo some extra processing beyond mere shaping and drilling such as color enhancement via dyes or irradiation.

The natural organics include bone, coral, horn, ivory, seeds (such as tagua nuts), animal shells, and wood. For most of human history, pearls were the ultimate precious beads of natural origin because of their rarity; the modern pearl-culturing process has made them far more common. Amber and jet are also of natural organic origin although both are the result of partial fossilization.

The natural inorganics include various types of stones, ranging from gemstones to common minerals, and metals. Of the latter, only a few precious metals occur in pure forms, but other purified base metals may as well be placed in this category along with certain naturally occurring alloys such as electrum.

Synthetic materials

The oldest-surviving synthetic materials used for bead making have generally been ceramics: pottery and glass. Beads were also made from ancient alloys such as bronze and brass, but as those were more vulnerable to oxidation they have generally been less well-preserved at archaeological sites.

Many different subtypes of glass are now used for beadmaking, some of which have their component-specific names. Lead crystal beads have a high percentage of lead oxide in the glass formula, increasing the refractive index. Most of the other named glass types have their formulations and patterns inseparable from the manufacturing process.

Small, colorful, fusible plastic beads can be placed on a solid plastic-backed peg array to form designs and then melted together with a clothes iron; alternatively, they can be strung into necklaces and bracelets or woven into keychains. Fusible beads come in many colors and degrees of transparency/opacity, including varieties that glow in the dark or have internal glitter; peg boards come in various shapes and several geometric patterns. Plastic toy beads, made by chopping plastic tubes into short pieces, were introduced in 1958 by Munkplast AB in Munka-Ljungby, Sweden. Known as Indian beads, they were originally sewn together to form ribbons. The pegboard for bead designs was invented in the early 1960s (patented 1962, patent granted 1967) by Gunnar Knutsson in Vällingby, Sweden, as a therapy for elderly homes; the pegboard later gained popularity as a toy for children.[1] The bead designs were glued to cardboard or Masonite boards and used as trivets. Later, when the beads were made of polyethylene, it became possible to fuse them with a flat iron. Hama come in three sizes: mini (diameter 2 mm (0.079 in)), midi (5 mm (0.20 in)) and maxi (10 mm (0.39 in)).[2] Perler beads come in two sizes called classic (5 mm) and biggie (10 mm). Pyssla beads (by IKEA) only come in one size (5 mm).

Manufacturing
Modern mass-produced beads are generally shaped by carving or casting, depending on the material and desired effect. In some cases, more specialized metalworking or glassworking techniques may be employed, or a combination of multiple techniques and materials may be used such as in cloisonné.

Beads are small circular shapes that come in different shapes and sizes. The materials are made from different qualities such as color, shape, shine, pattern, or even exotic materials used, etc. In making beads, they have to have holes in the center in putting through a string to hold the beads together using different techniques that can help. Some archaeologists had been working at Blombos cave located in South Africa, there was a recent discovery showing forty-one marine shell (Nassarius kraussianus) beads. It was estimated that it was made about seventy-five thousand years ago.

Glassworking
Most glass beads are pressed glass, mass-produced by preparing a molten batch of glass of the desired color and pouring it into molds to form the desired shape. This is also true of most plastic beads.

A smaller and more expensive subset of glass and lead crystal beads are cut into precise faceted shapes on an individual basis. This was once done by hand but has largely been taken over by precision machinery.

"Fire-polished" faceted beads are a less expensive alternative to hand-cut faceted glass or crystal. They derive their name from the second half of a two-part process: first, the glass batch is poured into round bead molds, then they are faceted with a grinding wheel. The faceted beads are then poured onto a tray and briefly reheated just long enough to melt the surface, "polishing" out any minor surface irregularities from the grinding wheel.

Specialized glass techniques and types
There are several specialized glassworking techniques that create a distinctive appearance throughout the body of the resulting beads, which are then primarily referred to by the glass type.

If the glass batch is used to create a large massive block instead of pre-shaping it as it cools, the result may then be carved into smaller items in the same manner as stone. Conversely, glass artisans may make beads by lampworking the glass on an individual basis; once formed, the beads undergo little or no further shaping after the layers have been properly annealed.

Most of these glass subtypes are some form of fused glass, although goldstone is created by controlling the reductive atmosphere and cooling conditions of the glass batch rather than by fusing separate components together.

Dichroic glass beads incorporate a semitransparent microlayer of metal between two or more layers. Fibre optic glass beads have an eyecatching chatoyant effect across the grain.

There are also several ways to fuse many small glass canes together into a multicolored pattern, resulting in millefiori beads or chevron beads (sometimes called "trade beads"). "Furnace glass" beads encase a multicolored core in a transparent exterior layer which is then annealed in a furnace.

More economically, millefiori beads can also be made by limiting the patterning process to long, narrow canes or rods known as murrine. Thin cross-sections, or "decals", can then be cut from the murrine and fused into the surface of a plain glass bead.

Shapes
Beads can be made in variety of shapes, including the following, as well as tubular and oval-shaped beads.

Round
This is the most common shape of beads that are strung on wire to create necklaces, and bracelets. The shape of the round beads lay together and are pleasing to the eye. Round beads can be made of glass, stone, ceramic, metal, or wood.

Square or cubed
Square beads can be to enhance a necklace design as a spacer however a necklace can be strung with just square beads. The necklaces with square beads are used in Rosary necklaces/prayer necklaces, and wooden or shell ones are made for beachwear.

Hair pipe beads
Elk rib bones were the original material for the long, tubular hair pipe beads. Today these beads are commonly made of bison and water buffalo bones and are popular for breastplates and chokers among Plains Indians. Black variations of these beads are made from the animals' horns.

Seed beads
Seed beads are uniformly shaped spheroidal or tube shaped beads ranging in size from under a millimetre to several millimetres. "Seed bead" is a generic term for any small bead. Usually rounded in shape, seed beads are most commonly used for loom and off-loom bead weaving.

Place or period of origin

 * African trade beads or slave beads may be antique beads that were manufactured in Europe and used for trade during the colonial period, such as chevron beads; or they may have been made in West Africa by and for Africans, such as Mauritanian Kiffa beads, Ghanaian and Nigerian powder glass beads, or African-made brass beads. Archaeologists have documented that as recently as the late-nineteenth century beads manufactured in Europe continued to accompany exploration of Africa using Indigenous routes into the interior.
 * Austrian crystal is a generic term for cut lead-crystal beads, based on the location and prestige of the Swarovski firm.
 * Czech glass beads are made in the Czech Republic, in particular an area called Jablonec nad Nisou. Production of glass beads in the area dates back to the 14th century, though production was depressed under communist rule. Because of this long tradition, their workmanship and quality has an excellent reputation.
 * Islamic glass beads have been made in a wide geographical and historical range of Islamic cultures. Used and manufactured from medieval Spain and North Africa in the West and to China in the East, they can be identified by recognizable features, including styles and techniques.
 * Vintage beads, in the collectibles and antique market, refers to items that are at least 25 or more years old. Vintage beads are available in materials that include lucite, plastic, crystal, metal and glass.
 * With beads being something that's popular, people are drawn to them and are intrigued to know more about them. People like archaeologists, beadmakers, collectors etc. are interested in beads in knowing more about them and doing research.

Miscellaneous ethnic beads
Tibetan Dzi beads and Rudraksha beads are used to make Buddhist and Hindu rosaries (malas). Magatama are traditional Japanese beads, and cinnabar was often used for making beads in China. Wampum are cylindrical white or purple beads made from quahog or North Atlantic channeled whelk shells by northeastern Native American tribes, such as the Wampanoag and Shinnecock. Job's tears are seed beads popular among southeastern Native American tribes. Heishe are beads made of shells or stones by the Kewa Pueblo people of New Mexico.

Symbolic meaning of beads
In many parts of the world, beads are used for symbolic purposes, for example:

 * use for prayer or devotion - e.g. rosary beads for Roman Catholics and many other Christians, misbaha for Shia and many other Muslims, japamala/nenju for Hindus, Buddhists, Jains, some Sikhs, Confucianism, Taoists/Daoists, Shinto, etc.
 * use for anti-tension devices, e.g. Greek komboloi, or worry beads.
 * use as currency e.g. Aggrey beads from Ghana.
 * use for gaming e.g. oware beads for mancala.
 * Different religions around the world like Hinduism, Buddhism, Christianity, and many more had a role to play. Beads were used to carry letters, patterns, and ideas in counting prayers. In the medieval times era, it was common to use prayer beads in different classes. The materials that were fashioned to make them were stones, metal including bones.

History
Beads are thought to be one of the earliest forms of trade between members of the human race. It is believed that bead trading was one of the reasons why humans developed language.[1] Beads are said to have been used and traded for most of human history. The oldest beads found to date were at Blombos Cave, about 72,000 years old, and at Ksar Akil[2] in Lebanon, about 40,000 years old.

Surface patterns
After shaping, glass and crystal beads can have their surface appearance enhanced by etching a translucent frosted layer, applying an additional color layer, or both. Aurora Borealis, or AB, is a surface coating that diffuses light into a rainbow. Other surface coatings are vitrail, moonlight, dorado, satin, star shine, and heliotrope.

 * Faux beads are beads that are made to look like a more expensive original material, especially in the case of fake pearls and simulated rocks, minerals and gemstones. Precious metals and ivory are also imitated.

Tagua nuts from South America are used as an ivory substitute since the natural ivory trade has been restricted worldwide.

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Bead weaving

Bead weaving (or beadweaving) is a set of techniques for weaving sheets and objects of seed beads. Threads are strung through and/or around the beads to hold them together. It can be done either on a loom or using one of a number of off-loom stitches.

On-loom beadweaving
When weaving on a loom, the beads are strung on the weft threads and locked in between the warp threads. Although loomed pieces are typically rectangular, it is possible to increase and decrease to produce angular or curvy shapes. Fringe can also be added during weaving or before the piece is removed from the loom.

Frame looms
The most common modern loom bead weaving technique requires two passes of the weft thread per row of beads. First, an entire row of beads is strung on the weft thread. Then the beads are pressed in between the warp threads from below. Then the needle is passed back through the beads, but above the warp threads, to lock the beads into place.

Bead looms vary in size and are typically made of wood or metal. Usually, a comb or spring is used to hold the warp threads a bead-width apart (the lede image shows a threaded rod). Some looms have roller bars; these allow the weaver to produce pieces that are longer than the loom. Most looms are meant to sit on a table, but some have floor stands or are meant to sit in the lap. Cheap bead looms are sometimes made from styrofoam trays, wrapping the warp through evenly-spaced small slits notched into opposite edges.

Heddle looms
Heddle bead looms were popular in the United States near the beginning of the 20th century. They allow weaving of beads by raising every other thread and inserting strung beads in the shed, the space between the lowered and raised threads. There are still a few heddle bead looms being manufactured today. The most difficult part of loomwork is finishing off the warp threads.

Off-loom beadweaving

Off-loom beadweaving is a family of beadwork techniques in which seed beads are woven together into a flat fabric, a tubular rope, or a three-dimensional object such as a ball, clasp, box, or a piece of jewelry. Most off-loom techniques can be accomplished using a single needle and thread (no warp threads), and some have two-needle variations. Different stitches produce pieces with distinct textures, shapes, and patterns. There are many different off-loom bead stitches, including new stitches (distinct thread paths) published as recently as 2015: Spiral Bead Weaving Stitches
 * albion stitch, developed by Heather Kingsley-Heath, published May 2009
 * brick stitch, also known as Comanche or Cheyenne stitch
 * chevron stitch, a triangular form of bead netting
 * diamond weave, developed over a number of years by Gerlinde Lenz, published August 2015
 * herringbone stitch, also known as Ndebele stitch
 * hubble stitch and wave hubble stitch, created and developed by Melanie de Miguel, published 2015
 * netting, to avoid confusion specifically bead netting
 * peyote stitch, also known as gourd stitch
 * plaiting, crossing multiple threads as in a plait or braid, using beads to connect the crossings
 * pondo stitch, also known as African circle stitch
 * right-angle weave
 * Saint Petersburg chain
 * square stitch, an off loom stitch that mimics the look of loomed bead projects.
 * ladder stitch, a foundation stitch that is used to build a base for brick stitch or herringbone stitch.
 * triangle weave
 * Cellini spiral, a tubular peyote stitch
 * Dutch spiral
 * African helix
 * Russian spiral
 * Chenille

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

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Branchiopoda

Branchiopoda is a class of crustaceans. It comprises fairy shrimp, clam shrimp, Diplostraca (or Cladocera), Notostraca, the Devonian Lepidocaris and possibly the Cambrian Rehbachiella. They are mostly small, freshwater animals that feed on plankton and detritus.

Description
Members of the Branchiopoda are unified by the presence of gills on many of the animals' appendages, including some of the mouthparts. This is also responsible for the name of the group (from the βράγχια, gills, akin to βρόγχος, windpipe; πούς, foot). They generally possess compound eyes and a carapace, which may be a shell of two valves enclosing the trunk (as in most Cladocera), broad and shallow (as in the Notostraca), or entirely absent (as in the Anostraca). In the groups where the carapace prevents the use of the trunk limbs for swimming (Cladocera and clam shrimp), the antennae are used for locomotion, as they are in the nauplius. Male fairy shrimp have an enlarged pair of antennae with which they grasp the female during mating, while the bottom-feeding Notostraca, the antennae are reduced to vestiges. The trunk limbs are beaten in a metachronal rhythm, causing a flow of water along the midline of the animal, from which it derives oxygen, food and, in the case of the Anostraca and Notostraca, movement.

Ecology
Branchiopods are found in continental fresh water, including temporary pools and in hypersaline lakes, and some in brackish water. Only in two groups of water fleas do we find marine species: Family Podonidae in the order Diplostraca, and family Sididae in the order Diplostraca. Most branchiopodans eat floating detritus or plankton, which they take using the setae on their appendages. But notostracans are omnivorous and very opportunistic feeders and will eat algae and bacteria in addition to animals as both predators and scavengers.

Taxonomy
In early taxonomic treatments, the current members of the Branchiopoda were all placed in a single genus, Monoculus. The taxon Branchiopoda was erected by Pierre André Latreille in 1817, initially at the rank of order.

The current upper-level classification of Branchiopoda, according to the World Register of Marine Species (2021), is as follows:

Class Branchiopoda Latreille, 1817
 * Subclass Sarsostraca Tasch, 1969
 * Order Anostraca Sars, 1867
 * Suborder Anostracina Weekers et al., 2002
 * Suborder Artemiina Weekers et al., 2002
 * Subclass Phyllopoda Preuss, 1951
 * Superorder Diplostraca Gerstaecker, 1866
 * Order Anomopoda G.O. Sars, 1865
 * Order Ctenopoda G.O. Sars, 1865
 * Order Cyclestherida Sars G.O., 1899
 * Order Haplopoda G.O. Sars, 1865
 * Order Laevicaudata Linder, 1945
 * Order Onychopoda G.O. Sars, 1865
 * Order Spinicaudata Linder, 1945
 * Order Notostraca G. O. Sars, 1867
 * Genus †Cryptocaris Barrande, 1872
 * Genus †Dithyrocaris

In addition, the extinct genus Lepidocaris is generally placed in Branchiopoda.

Anostraca

The fairy shrimp of the order Anostraca are usually 6 - 25 mm long (exceptionally up to 170 mm). Most species have 20 body segments, bearing 11 pairs of leaf-like phyllopodia (swimming legs), and the body lacks a carapace. They live in vernal pools and hypersaline lakes across the world, including pools in deserts, in ice-covered mountain lakes and in Antarctica. They swim "upside-down" and feed by filtering organic particles from the water or by scraping algae from surfaces. They are an important food for many birds and fish, and are cultured and harvested for use as fish food. There are 300 species spread across 8 families.

Lipostraca
Lipostraca contains a single extinct Early Devonian species, Lepidocaris rhyniensis, which is the most abundant animal in the Rhynie chert deposits. It resembles modern Anostraca, to which it is probably closely related, although its relationships to other orders remain unclear. The body is 3 mm long, with 23 body segments and 19 pairs of appendages, but no carapace. It occurred chiefly among charophytes, probably in alkaline temporary pools.

Notostraca
The order Notostraca comprises the single family Triopsidae, containing the tadpole shrimp or shield shrimp. The two genera, Triops and Lepidurus, are considered living fossils, having not changed significantly in outward form since the Triassic. They have a broad, flat carapace, which conceals the head and bears a single pair of compound eyes. The abdomen is long, appears to be segmented and bears numerous pairs of flattened legs. The telson is flanked by a pair of long, thin caudal rami. Phenotypic plasticity within taxa makes species-level identification difficult, and is further compounded by variation in the mode of reproduction. The evidence of phenotypic plasticity of Arctic tadpole shrimp (Lepidurus arcticus, Notostraca) has been observed in Svalbard. Notostracans are the largest branchiopodans and are omnivores living on the bottom of temporary pools, ponds and shallow lakes.

Laevicaudata, Spinicaudata and Cyclestherida (once Conchostraca)
Clam shrimp are bivalved animals which have lived since at least the Devonian. The three groups are not believed to form a clade. They have 10–32 trunk segments, decreasing in size from front to back, and each bears a pair of legs which also carry gills. A strong muscle can close the two halves of the shell together.

Anomopoda, Ctenopoda, Onychopoda, and Haplopoda (once Cladocera)
These four orders make up a group of small crustaceans commonly called water fleas. Around 620 species have been recognised so far, with many more undescribed. They are ubiquitous in inland aquatic habitats, but rare in the oceans. Most are 0.2 - 6.0 mm long, with a down-turned head, and a carapace covering the apparently unsegmented thorax and abdomen. There is a single median compound eye. Most species show cyclical parthenogenesis, where asexual reproduction is occasionally supplemented by sexual reproduction, which produces resting eggs that allow the species to survive harsh conditions and disperse to distant habitats. In the water bodies of the world, a lot of Cladocera are non-native species, many of which pose a great threat to aquatic ecosystems.

Evolution
The fossil record of branchiopods extends back at least into the Upper Cambrian and possibly further. The group is thought to be monophyletic, with the Anostraca having been the first group to branch off. It is thought that the group evolved in the seas, but was forced into temporary pools and hypersaline lakes by the evolution of bony fishes. Although they were previously considered the sister group to the remaining crustaceans, it is now widely accepted that crustaceans form a paraphyletic group, and Branchiopoda are thought to be sister to a clade comprising Xenocarida (Remipedia and Cephalocarida) and Hexapoda (insects and their relatives).

title: Branchiopoda


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Baruch Spinoza

Baruch (de) Spinoza (24 November 1632 – 21 February 1677), also known under his Latinized pen name Benedictus de Spinoza, was a philosopher of Portuguese-Jewish origin. As a forerunner of the Age of Enlightenment, Spinoza significantly influenced modern biblical criticism, 17th-century rationalism, and Dutch intellectual culture, establishing himself as one of the most important and radical philosophers of the early modern period. Influenced by Stoicism, Thomas Hobbes, René Descartes, Ibn Tufayl, and heterodox Christians, Spinoza was a leading philosopher of the Dutch Golden Age.

Spinoza was born in Amsterdam to a Marrano family that fled Portugal for the more tolerant Dutch Republic. He received a traditional Jewish education, learning Hebrew and studying sacred texts within the Portuguese Jewish community, where his father was a prominent merchant. As a young man, Spinoza challenged rabbinic authority and questioned Jewish doctrines, leading to his permanent expulsion from the Jewish community in 1656. Following his excommunication, he distanced himself from all religious affiliations and devoted himself to philosophical inquiry and lens grinding. Spinoza attracted a dedicated circle of followers who gathered to discuss his writings and joined him in the intellectual pursuit of truth.

Spinoza published little to avoid persecution and bans on his books. In his Tractatus Theologico-Politicus, described by Steven Nadler as "one of the most important books of Western thought", Spinoza questioned the divine origin of the Hebrew Bible and the nature of God while arguing that ecclesiastic authority should have no role in a secular, democratic state. Ethics argues for a pantheistic view of God and explores the place of human freedom in a world devoid of theological, cosmological, and political moorings. Rejecting messianism and the emphasis on the afterlife, Spinoza emphasized appreciating and valuing life for ourselves and others. By advocating for individual liberty in its moral, psychological, and metaphysical dimensions, Spinoza helped establish the genre of political writing called secular theology.

Spinoza's philosophy spans nearly every area of philosophical discourse, including metaphysics, epistemology, political philosophy, ethics, philosophy of mind, and philosophy of science. His friends posthumously published his works, captivating philosophers for the next two centuries. Celebrated as one of the most original and influential thinkers of the seventeenth century, Rebecca Goldstein dubbed him "the renegade Jew who gave us modernity."

Family background
Spinoza's ancestors, adherents of Crypto-Judaism, faced persecution during the Portuguese Inquisition, enduring torture and public displays of humiliation. In 1597, his paternal grandfather's family left Vidigueira for Nantes and lived outwardly as New Christians, eventually transferring to Holland for an unknown reason. His maternal ancestors were a leading Oporto commercial family, and his maternal grandfather was a foremost merchant who drifted between Judaism and Christianity. Spinoza was raised by his grandmother from ages six to nine and probably learned much about his family history from her.

Spinoza's father Michael was a prominent and wealthy merchant in Amsterdam with a business that had wide geographical reach. In 1649, he was elected to serve as an administrative officer of the recently united congregation Talmud Torah. He married his cousin Rachael d’Espinosa, daughter of his uncle Abraham d’Espinosa, who was also a community leader and Michael's business partner. Marrying cousins was common in the Portuguese Jewish community then, giving Michael access to his father-in-law's commercial network and capital. Rachel's children died in infancy, and she died in 1627.

After the death of Rachel, Michael married Hannah Deborah, with whom he had five children. His second wife brought a dowry to the marriage that was absorbed into Michael's business capital instead of being set aside for her children, which may have caused a grudge between Spinoza and his father. The family lived on the artificial island on the south side of the River Amstel, known as the Vlooienburg, at the fifth house along the Houtgracht canal. The Jewish quarter was not formally divided. The family lived close to the Bet Ya'acov synagogue, and nearby were Christians, including the artist Rembrandt. Miriam was their first child, followed by Isaac who was expected to take over as head of the family and the commercial enterprise but died in 1649. Baruch Espinosa, the third child, was born on 24 November 1632 and named as per tradition for his maternal grandfather.

Spinoza's younger brother Gabriel was born in 1634, followed by another sister Rebecca. Miriam married Samuel de Caceres but died shortly after childbirth. According to Jewish practice, Samuel had to marry his former sister-in-law Rebecca. Following his brother's death, Spinoza's place as head of the family and its business meant scholarly ambitions were pushed aside. Spinoza's mother, Hannah Deborah, died when Spinoza was six years old. Michael's third wife, Esther, raised Spinoza from age nine; she lacked formal Jewish knowledge due to growing up a New Christian and only spoke Portuguese at home. The marriage was childless. Spinoza's sister Rebecca, brother Gabriel, and nephew eventually migrated to Curaçao, and the remaining family joined them after Spinoza's death.

Uriel da Costa's early influence
Through his mother, Spinoza was related to the philosopher Uriel da Costa, who stirred controversy in Amsterdam's Portuguese Jewish community. Da Costa questioned traditional Christian and Jewish beliefs, asserting that, for example, their origins were based on human inventions instead of God's revelation. His clashes with the religious establishment led to his excommunication twice by rabbinic authorities, who imposed humiliation and social exclusion. In 1639, as part of an agreement to be readmitted, da Costa had to prostrate himself for worshippers to step over him. He died in 1640, reportedly committing suicide.

During his childhood, Spinoza was likely unaware of his family connection with Uriel da Costa; still, as a teenager, he certainly heard discussions about him. Steven Nadler explains that, although da Costa died when Spinoza was eight, his ideas shaped Spinoza's intellectual development. Amsterdam's Jewish communities long remembered and discussed da Costa's skepticism about organized religion, denial of the soul's immortality, and the idea that Moses didn't write the Torah, influencing Spinoza's intellectual journey.

School days and the family business
Spinoza attended the Talmud Torah school adjoining the Bet Ya'acov synagogue, a few doors down from his home, headed by the senior Rabbi Saul Levi Morteira. Instructed in Spanish, the language of learning and literature, students in the elementary school learned to read the prayerbook and the Torah in Hebrew, translate the weekly section into Spanish, and study Rashi's commentary. Spinoza's name does not appear on the registry after age fourteen, and he likely never studied with rabbis such as Manasseh ben Israel and Morteira. Spinoza possibly went to work around fourteen and almost certainly was needed in his father's business after his brother died in 1649.

During the First Anglo-Dutch War, much of the Spinoza firm's ships and cargo were captured by English ships, severely affecting the firm's financial viability. The firm was saddled with debt by the war's end in 1654 due to its merchant voyages being intercepted by the English, leading to its decline. Spinoza's father died in 1654, making him the head of the family, responsible for organizing and leading the Jewish mourning rituals, and in a business partnership with his brother of their inherited firm. As Spinoza's father had poor health for some years before his death, he was significantly involved in the business, putting his intellectual curiosity on hold. Until 1656, he continued financially supporting the synagogue and attending services in compliance with synagogue conventions and practice. By 1655, the family's wealth had evaporated and the business effectively ended.

In March 1656, Spinoza went to the city authorities for protection against debts in the Portuguese Jewish community. To free himself from the responsibility of paying debts owed to his late father, Spinoza appealed to the city to declare him an orphan; since he was a legal minor, not understanding his father's indebtedness would remove the obligation to repay his debts and retrospectively renounce his inheritance. Though he was released of all debts and legally in the right, his reputation as a merchant was permanently damaged in addition to violating a synagogue regulation that business matters are to be arbitrated within the community.

Expulsion from the Jewish community

Amsterdam was tolerant of religious diversity so long as it was practiced discreetly. The community was concerned with protecting its reputation and not associating with Spinoza lest his controversial views provide the basis for possible persecution or expulsion. Spinoza did not openly break with Jewish authorities until his father died in 1654 when he became public and defiant, resulting from lengthy and stressful religious, financial, and legal clashes involving his business and synagogue, such as when Spinoza violated synagogue regulations by going to city authorities rather than resolving his disputes within the community to free himself from paying his father's debt.

On 27 July, 1656, the Talmud Torah community leaders, which included Aboab de Fonseca, issued a writ of herem against the 23-year-old Spinoza. Spinoza's censure was the harshest ever pronounced in the community, carrying tremendous emotional and spiritual impact. The exact reason for expelling Spinoza is not stated, only referring to his "abominable heresies", "monstrous deeds", and the testimony of witnesses "in the presence of the said Espinoza". Even though the Amsterdam municipal authorities were not directly involved in Spinoza's censure, the town council expressly ordered the Portuguese-Jewish community to regulate their conduct and ensure that the community kept strict observance of Jewish law. Other evidence indicates a concern about upsetting civil authorities, such as the synagogue's bans on public weddings, funeral processions, and discussing religious matters with Christians, lest such activity might "disturb the liberty we enjoy".

Before the expulsion, Spinoza had not published anything or written a treatise; Steven Nadler states that if Spinoza was voicing his criticism of Judaism that later appeared through his philosophical works, such as Part I of Ethics, then there can be no wonder that he was severely punished. Unlike most censures issued by the Amsterdam congregation, it was never rescinded since the censure did not lead to repentance. After the censure, Spinoza may have written an Apologia in Spanish defending his views, but it is now lost. Spinoza's expulsion did not lead him to convert to Christianity or belong to a confessional religion or sect. From 1656-61, Spinoza found lodgings elsewhere in Amsterdam and Leiden, supporting himself with teaching while learning lens grinding and constructing microscopes and telescopes. Spinoza did not maintain a sense of Jewish identity; he argued that without adherence to Jewish law, the Jewish people lacked a sustaining source of difference and identity, rendering the notion of a secular Jew incoherent.

Education and study group
Sometime between 1654 and 1657, Spinoza started studying Latin with political radical Franciscus van den Enden, a former Jesuit and atheist, who likely introduced Spinoza to scholastic and modern philosophy, including Descartes, who had a dominant influence on Spinoza's philosophy. While boarding with Van den Enden, Spinoza studied in his school, where he learned the arts and sciences and likely taught others. Many of his friends were either secularized freethinkers or belonged to dissident Christian groups that rejected the authority of established churches and traditional dogmas. Spinoza was acquainted with members of the Collegiants, a group of disaffected Mennonites and other dissenting Reformed sects that shunned official theology and must have played some role in Spinoza's developing views on religion and directed him to Van Enden. Jonathan Israel conjectures that another possible influential figure was atheist translator Jan Hendriksz Glazemaker, a collaborator of Spinoza's friend and publisher Rieuwertsz, who could not have mentored Spinoza but was in a unique position to introduce Spinoza to Cartesian philosophy, mathematics, and lens grinding.

After learning Latin with Van Enden, Spinoza studied at Leiden University around 1658, where he audited classes in Cartesian philosophy. From 1656-61, Spinoza's main discussion partners who formed his circle and played a formative part in Spinoza's life were Van den Enden, Pieter Balling, Jarig Jelles, Lodewijk Meyer, Johannes Bouwmeester and Adriaan Koerbagh. Spinoza's following, or philosophical sect, scrutinized the propositions of the Ethics while it was in draft and Spinoza's second text, Short Treatise on God, Man, and His Well-Being. Though a few prominent people in Amsterdam discussed the teachings of the secretive but marginal group, it was mainly a testing ground for Spinoza's philosophy to extend his challenge to the status quo. Their public reputation in Amsterdam was negative, with Ole Borch disparaging them as "atheists". Throughout his life, Spinoza's general approach was to avoid intellectual battles, clashes, and public controversies, viewing them as a waste of energy that served no real purpose.

Rijnsburg
Between 1660 and 1661, Spinoza moved from Amsterdam to Rijnsburg, allowing for a quiet retreat in the country and access to the university town, Leiden, where he still had many friends. Around this time, he wrote his Short Treatise on God, Man, and His Well-Being, which he never published in his lifetime, thinking it would enrage the theologians, synods, and city magistrates. The Short Treatise, a long-forgotten text that only survived in Dutch translation, was first published by Johannes van Vloten in 1862. While lodging with Herman Homan in Rijnsburg, Spinoza produced lenses and instruments to support himself and out of scientific interest. He began working on his Ethics and Descartes' Principles of Philosophy, which he completed in two weeks, communicating and interpreting Descartes' arguments and testing the water for his metaphysical and ethical ideas. Spinoza's explanations of essential elements of the Cartesian system helped many interested people study the system, enhancing his philosophical reputation. This work was published in 1663 and was one of the two works published in his lifetime under his name. Spinoza led a modest and frugal lifestyle, earning income by polishing lenses and crafting telescopes and microscopes. He also relied on the generous contributions of his friends to support himself.

Voorburg
In 1663, Spinoza moved to Voorburg for an unknown reason. He continued working on Ethics and corresponded with scientists and philosophers throughout Europe. In 1665, he began writing the Theological-Political Treatise, which addresses theological and political issues such as the interpretation of scripture, the origins of the state, and the bounds of political and religious authority while arguing for a secular, democratic state. Before the publication of the Theological-Political Treatise, Spinoza's friend Adriaan Koerbagh published a book that criticized organized religion, denied the divine authorship of the Bible, and asserted that miracles were impossible—ideas similar to those of Spinoza. His work attracted the attention of the authorities, leading to his imprisonment and eventual death in prison. Anticipating the reaction to his ideas, Spinoza published his treatise in 1670 under a false publisher and a fictitious place of publication. The work did not remain anonymous for long. Samuel Maresius attacked Spinoza personally, while Thomas Hobbes and Johannes Bredenburg criticized his conception of God and saw the book as dangerous and subversive. Spinoza's work was safer than Koerbagh's because it was written in Latin, a language not widely understood by the general public, and Spinoza explicitly forbade its translation. The secular authorities varied enforcing the Reformed Church in Amsterdam's orders to ban the distribution of the blasphemous book.

The Hague
In 1670, Spinoza moved to The Hague to have easier access to the city's intellectual life and to be closer to his friends and followers. As he became more famous, Spinoza spent time receiving visitors and responding to letters. He returned to the manuscript of Ethics, reworking part Three into parts Four and Five, and composed a Hebrew grammar for proper interpretation of scripture and for clearing up confusion and problems when studying the Bible, with part One presenting etymology, the alphabet, and principles governing nouns, verbs, and more. Part Two, unfinished before he died, would have presented syntax rules. Another unfinished work from 1676 was Tractatus Politicus, which concerns how states can function well and intended to show that democratic states are best. Spinoza refused an offer to be the chair of philosophy at the University of Heidelberg, perhaps because of the possibility that it might curb his freedom of thought.

Correspondence
Few of Spinoza's letters are extant, and none before 1661. Nearly all the contents are philosophical and technical because the original editors of Opera Posthuma—a collection of his works published posthumously—Lodewijk Meyer, Georg Hermann Schuller, and Johannes Bouwmeester, excluded personal matters and letters due to the political and ecclesiastical persecution of the time. Spinoza corresponded with Peter Serrarius, a radical Protestant and millenarian merchant, who was a patron of Spinoza after his expulsion from the Jewish community. He acted as an intermediary for Spinoza's correspondence, sending and receiving letters of the philosopher to and from third parties. They maintained their relationship until Serrarius died in 1669.

Through his pursuits in lens grinding, mathematics, optics, and philosophy, Spinoza forged connections with prominent figures such as scientist Christiaan Huygens, mathematician Johannes Hudde, and Secretary of the British Royal Society Henry Oldenburg. Huygens and others notably praised the quality of Spinoza's lenses. Spinoza engaged in correspondence with Willem van Blijenbergh, an amateur Calvinist theologian, who sought Spinoza's view on the nature of evil and sin. Whereas Blijenbergh deferred to the authority of scripture for theology and philosophy, Spinoza told him not solely to look at scripture for truth or anthropomorphize God. Also, Spinoza told him their views were incommensurable. Gottfried Wilhelm Leibniz outwardly described Spinoza's work negatively but privately wrote letters to him and desired to examine the manuscript of the Ethics. In 1676, Leibniz traveled to The Hague to meet Spinoza, remaining with him for three days to converse about current events and philosophy. Leibniz's work bears some striking resemblances to parts of Spinoza's philosophy, like in Monadology. Leibniz was concerned when his name was not redacted in a letter printed in the Opera Posthuma. In 1675, Albert Burgh, a friend and possibly former pupil of Spinoza, wrote to him repudiating his teachings and announcing his conversion to the Catholic Church. Burgh attacked Spinoza's views as expressed in the Theological-Political Treatise and tried to persuade Spinoza to embrace Catholicism. In response, Spinoza, at the request of Burgh's family, who hoped to restore his reason, wrote an angry letter mocking the Catholic Church and condemning all religious superstition.

Spinoza published little in his lifetime, and most formal writings were in Latin, reaching few readers. Apart from Descartes' Principles of Philosophy and the Theologico-Political Treatise, his works appeared in print after his death. Because the reaction to his anonymously published work, Theologico-Political Treatise, was unfavorable, Spinoza told supporters not to translate his works and abstained from publishing further. Following his death, his supporters published his works posthumously in Latin and Dutch. His posthumous works–Opera Posthuma–were edited by his friends in secrecy to prevent the confiscation and destruction of manuscripts. He wore a signet ring to mark his letters, engraved with the Latin word Caute, meaning "Caution", and the image of a thorny rose.

Death and rescue of unpublished writings
Spinoza's health began to fail in 1676, and he died in The Hague on 21 February 1677 at age 44, attended by a physician friend, Georg Herman Schuller. Spinoza had been ill with some form of lung affliction, probably tuberculosis and possibly complicated by silicosis brought on by grinding glass lenses. Although Spinoza had been becoming sicker for weeks, his death was sudden, and he died without leaving a will. Reports circulated that he repented his philosophical stances on his deathbed, but these tales petered out in the 18th century. Lutheran preacher Johannes Colerus wrote the first biography of Spinoza for the original reason of researching his final days.

Spinoza was buried inside the Nieuwe Kerk four days after his death, with six others in the same vault. At the time, there was no memorial plaque for Spinoza. In the 18th century, the vault was emptied, and the remnants scattered over the earth of the churchyard. The memorial plaque is outside the church, where some of his remains are part of the churchyard's soil. Spinoza's friends rescued his personal belongings, papers, and unpublished manuscripts. His supporters took them away for safekeeping from seizure by those wishing to suppress his writings, and they do not appear in the inventory of his possessions at death. Within a year of his death, his supporters translated his Latin manuscripts into Dutch and other languages. Secular authorities and later the Roman Catholic Church banned his works.

Tractatus Theologico-Politicus (TTP)

Despite being published in Latin rather than a vernacular language, this 1670 treatise published in Spinoza's lifetime caused a huge reaction described as "one of the most significant events in European intellectual history."

Ethics
The Ethics has been associated with that of Leibniz and René Descartes as part of the rationalist school of thought, which includes the assumption that ideas correspond to reality perfectly, in the same way that mathematics is supposed to be an exact representation of the world. The Ethics contains many unresolved obscurities and is written with a forbidding mathematical structure modeled on Euclid's geometry and has been described as a "superbly cryptic masterwork". The writings of René Descartes have been described as "Spinoza's starting point". Spinoza's first publication was his 1663 geometric exposition of proofs using Euclid's model with definitions and axioms of Descartes' Principles of Philosophy. Following Descartes, Spinoza aimed to understand truth through logical deductions from 'clear and distinct ideas', a process which always begins from the 'self-evident truths' of axioms. However, his actual project does not end there: from his first work to his last one, there runs a thread of "attending to the highest good" (which also is the highest truth) and thereby achieving a state of peace and harmony, either metaphysically or politically. In this light, the Principles of Philosophy might be viewed as an "exercise in geometric method and philosophy", paving the way for numerous concepts and conclusions that would define his philosophy (see Cogitata Metaphysica).

Metaphysics
Spinoza's metaphysics consists of one thing, substance, and its modifications (modes). Early in The Ethics Spinoza argues that only one substance is absolutely infinite, self-caused, and eternal. He calls this substance "God", or "Nature". He takes these two terms to be synonymous (in the Latin the phrase he uses is "Deus sive Natura"). For Spinoza, the whole of the natural universe consists of one substance, God, or, what is the same, Nature, and its modifications (modes). "It cannot be overemphasized how the rest of Spinoza's philosophy—his philosophy of mind, his epistemology, his psychology, his moral philosophy, his political philosophy, and his philosophy of religion—flows more or less directly from the metaphysical underpinnings in Part I of the Ethics."

Substance, attributes, and modes
"Spinoza sets forth a vision of Being, illuminated by his awareness of God. They may seem strange at first sight. To the question 'What is?' he replies: 'Substance, its attributes, and modes'."

Following Maimonides, Spinoza defined substance as "that which is in itself and is conceived through itself", meaning that it can be understood without any reference to anything external. Being conceptually independent also means that the same thing is ontologically independent, depending on nothing else for its existence and being the 'cause of itself' (causa sui). A mode is something which cannot exist independently but rather must do so as part of something else on which it depends, including properties (for example color), relations (such as size) and individual things. Modes can be further divided into 'finite' and 'infinite' ones, with the latter being evident in every finite mode (he gives examples of "motion" and "rest"). The traditional understanding of an attribute in philosophy is similar to Spinoza's modes, though he uses that word differently. To him, an attribute is "that which the intellect perceives as constituting the essence of substance", and there are possibly an infinite number of them. It is the essential nature that is "attributed" to reality by intellect.

Spinoza defined God as "a substance consisting of infinite attributes, each of which expresses eternal and infinite essence", and since "no cause or reason" can prevent such a being from existing, it must exist. This is a form of the ontological argument, which is claimed to prove the existence of God, but Spinoza went further in stating that it showed that only God exists. Accordingly, he stated that "Whatever is, is in God, and nothing can exist or be conceived without God". This means that God is identical with the universe, an idea which he encapsulated in the phrase "Deus sive Natura" ('God or Nature'), which some have interpreted as atheism or pantheism. Though there are many more of them, God can be known by humans either through the attribute of extension or the attribute of thought. Thought and extension represent giving complete accounts of the world in mental or physical terms. To this end, he says that "the mind and the body are one and the same thing, which is conceived now under the attribute of thought, now under the attribute of extension".

After stating his proof for God's existence, Spinoza addresses who "God" is. Spinoza believed that God is "the sum of the natural and physical laws of the universe and certainly not an individual entity or creator". Spinoza attempts to prove that God is just the substance of the universe by first stating that substances do not share attributes or essences and then demonstrating that God is a "substance" with an infinite number of attributes, thus the attributes possessed by any other substances must also be possessed by God. Therefore, God is just the sum of all the substances of the universe. God is the only substance in the universe, and everything is a part of God. This view was described by Charles Hartshorne as Classical Pantheism.

Spinoza argues that "things could not have been produced by God in any other way or in any other order than is the case". Therefore, concepts such as 'freedom' and 'chance' have little meaning. This picture of Spinoza's determinism is illuminated in Ethics: "the infant believes that it is by free will that it seeks the breast; the angry boy believes that by free will he wishes vengeance; the timid man thinks it is with free will he seeks flight; the drunkard believes that by a free command of his mind he speaks the things which when sober he wishes he had left unsaid. … All believe that they speak by a free command of the mind, whilst, in truth, they have no power to restrain the impulse which they have to speak." In his letter to G. H. Schuller (Letter 58), he wrote: "men are conscious of their desire and unaware of the causes by which [their desires] are determined." He also held that knowledge of true causes of passive emotion can transform it into an active emotion, thus anticipating one of the key ideas of Sigmund Freud's psychoanalysis.

According to Eric Schliesser, Spinoza was skeptical regarding the possibility of knowledge of nature and as a consequence at odds with scientists such as Galileo and Huygens.

Causality
Although the principle of sufficient reason is commonly associated with Gottfried Leibniz, Spinoza employs it in a more systematic manner. In Spinoza's philosophical framework, questions concerning why a particular phenomenon exists are always answerable, and these answers are provided in terms of the relevant cause. Spinoza's approach involves first providing an account of a phenomenon, such as goodness or consciousness, to explain it, and then further explaining the phenomenon in terms of itself. For instance, he might argue that consciousness is the degree of power of a mental state.

Spinoza has also been described as an "Epicurean materialist", specifically in reference to his opposition to Cartesian mind-body dualism. This view was held by Epicureans before him, as they believed that atoms with their probabilistic paths were the only substance that existed fundamentally. Spinoza, however, deviated significantly from Epicureans by adhering to strict determinism, much like the Stoics before him, in contrast to the Epicurean belief in the probabilistic path of atoms, which is more in line with contemporary thought on quantum mechanics.

The emotions
One thing which seems, on the surface, to distinguish Spinoza's view of the emotions from both Descartes' and Hume's pictures of them is that he takes the emotions to be cognitive in some important respect. Jonathan Bennett claims that "Spinoza mainly saw emotions as caused by cognitions. [However] he did not say this clearly enough and sometimes lost sight of it entirely." Spinoza provides several demonstrations which purport to show truths about how human emotions work. The picture presented is, according to Bennett, "unflattering, coloured as it is by universal egoism".

Ethical philosophy

Spinoza's notion of blessedness figures centrally in his ethical philosophy. Spinoza writes that blessedness (or salvation or freedom), "consists, namely, in a constant and eternal love of God, or in God's love for men. Philosopher Jonathan Bennett interprets this as Spinoza wanting "'blessedness' to stand for the most elevated and desirable state one could possibly be in." Understanding what is meant by "most elevated and desirable state" requires understanding Spinoza's notion of conatus (striving, but not necessarily with any teleological baggage) and that "perfection" refers not to (moral) value, but to completeness. Given that individuals are identified as mere modifications of the infinite Substance, it follows that no individual can ever be fully complete, i.e., perfect, or blessed. Absolute perfection, is, in Spinoza's thought, reserved solely for Substance. Nevertheless, modes can attain a lesser form of blessedness, namely, that of pure understanding of oneself as one really is, i.e., as a definite modification of Substance in a certain set of relationships with everything else in the universe. That this is what Spinoza has in mind can be seen at the end of the Ethics, in E5P24 and E5P25, where Spinoza makes two final key moves, unifying the metaphysical, epistemological, and ethical propositions he has developed over the course of the work. In E5P24, he links the understanding of particular things to the understanding of God, or Substance; in E5P25, the conatus of the mind is linked to the third kind of knowledge (Intuition). From here, it is a short step to the connection of Blessedness with the amor dei intellectualis ("intellectual love of God").

Tractatus Politicus (Political Treatise) (TP)
This unfinished treatise in Latin expounds Spinoza's ideas about forms of government. As with the Ethics, this work was published posthumously by his circle of supporters in Latin and in Dutch. The subtitle is "In quo demonstratur, quomodo Societas, ubi Imperium Monarchicum locum habet, sicut et ea, ubi Optimi imperant, debet institui, ne in Tyrannidem labatur, et ut Pax, Libertasque civium inviolata maneat." ("In which it is demonstrated how a society, may it be a monarchy or an aristocracy, can be best governed, so as not to fall into tyranny, and so that the peace and liberty of the citizens remain unviolated").

Although Spinoza's political and theological thought was radical on many ways, he held traditional views on the place of women. In the TP, he writes briefly on the last page of the TP that women were “naturally” subordinate to men, stating bluntly his women are “by nature” not by “institutional practice” subordinate to men. Both his major biographers in English remark on his view of women. Biographer Steven Nadler is clearly disappointed by Spinoza's only statement on women. “It is unfortunate that the very last words we have by him, at the end of the extant chapters of the Political Treatise, are a short digression … on the unsuitability of women to hold political power.” Likewise Jonathan I. Israel says that Spinoza's views are “hugely disappointing to the modern reader” and that most that can be said in his defense is that “in his age rampant tyrannizing over women was indeed universal.” He goes on to say, "one may legitimately wonder why did Spinoza, if he was to be consistent, not apply his highly sceptical and innovative, for his time uniquely subversive, de-legtimizing general principle likewise to men's tyrannizing over women." One scholar has attempted to rationalize Spinoza's views excluding women from full citizenship. But the topic has not attracted major consideration in Spinoza studies.

Pantheism
Spinoza was considered to be an atheist because he used the word "God" [Deus] to signify a concept that was different from that of traditional Judeo–Christian monotheism. "Spinoza expressly denies personality and consciousness to God; he has neither intelligence, feeling, nor will; he does not act according to purpose, but everything follows necessarily from his nature, according to law...." Thus, Spinoza's cool, indifferent God differs from the concept of an anthropomorphic, fatherly God who cares about humanity.

In 1785, Friedrich Heinrich Jacobi published a condemnation of Spinoza's pantheism, after Gotthold Lessing was thought to have confessed on his deathbed to being a "Spinozist", which was the equivalent in his time of being called an atheist. Jacobi claimed that Spinoza's doctrine was pure materialism, because all Nature and God are said to be nothing but extended substance. This, for Jacobi, was the result of Enlightenment rationalism and it would finally end in absolute atheism. Moses Mendelssohn disagreed with Jacobi, saying that there is no actual difference between theism and pantheism. The issue became a major intellectual and religious concern for European civilization at the time.

The attraction of Spinoza's philosophy to late 18th-century Europeans was that it provided an alternative to materialism, atheism, and deism. Three of Spinoza's ideas strongly appealed to them: By 1879, Spinoza's pantheism was praised by many, but was considered by some to be alarming and dangerously inimical.
 * the unity of all that exists;
 * the regularity of all that happens;
 * the identity of spirit and nature.

Spinoza's "God or Nature" (Deus sive Natura) provided a living, natural God, in contrast to Isaac Newton's first cause argument and the dead mechanism of Julien Offray de La Mettrie's (1709–1751) work, Man a Machine (L'homme machine). Coleridge and Shelley saw in Spinoza's philosophy a religion of nature. Novalis called him the "God-intoxicated man". Spinoza inspired the poet Shelley to write his essay "The Necessity of Atheism".

It is a widespread belief that Spinoza equated God with the material universe. He has therefore been called the "prophet" and "prince" and most eminent expounder of pantheism. More specifically, in a letter to Henry Oldenburg he states, "as to the view of certain people that I identify God with Nature (taken as a kind of mass or corporeal matter), they are quite mistaken". For Spinoza, the universe (cosmos) is a mode under two attributes of Thought and Extension. God has infinitely many other attributes which are not present in the world.

According to German philosopher Karl Jaspers (1883–1969), when Spinoza wrote Deus sive Natura (Latin for 'God or Nature'), Spinoza meant God was natura naturans (nature doing what nature does; literally, 'nature naturing'), not natura naturata (nature already created; literally, 'nature natured'). Jaspers believed that Spinoza, in his philosophical system, did not mean to say that God and Nature are interchangeable terms, but rather that God's transcendence was attested by his infinitely many attributes, and that two attributes known by humans, namely Thought and Extension, signified God's immanence. Even God under the attributes of thought and extension cannot be identified strictly with our world. That world is of course "divisible"; it has parts. But Spinoza said, "no attribute of a substance can be truly conceived from which it follows that the substance can be divided", meaning that one cannot conceive an attribute in a way that leads to division of substance. He also said, "a substance which is absolutely infinite is indivisible" (Ethics, Part I, Propositions 12 and 13). Following this logic, our world should be considered as a mode under two attributes of thought and extension. Therefore, according to Jaspers, the pantheist formula "One and All" would apply to Spinoza only if the "One" preserves its transcendence and the "All" were not interpreted as the totality of finite things.

Martial Guéroult (1891–1976) suggested the term panentheism, rather than pantheism to describe Spinoza's view of the relation between God and the world. The world is not God, but in a strong sense, "in" God. Not only do finite things have God as their cause; they cannot be conceived without God. However, American panentheist philosopher Charles Hartshorne (1897–2000) insisted on the term Classical Pantheism to describe Spinoza's view.

According to the Stanford Encyclopedia of Philosophy, Spinoza's God is an "infinite intellect" (Ethics 2p11c) — all-knowing (2p3), and capable of loving both himself—and us, insofar as we are part of his perfection (5p35c). And if the mark of a personal being is that it is one towards which we can entertain personal attitudes, then we should note too that Spinoza recommends amor intellectualis dei (the intellectual love of God) as the supreme good for man (5p33). However, the matter is complex. Spinoza's God does not have free will (1p32c1), he does not have purposes or intentions (1 appendix), and Spinoza insists that "neither intellect nor will pertain to the nature of God" (1p17s1). Moreover, while we may love God, we need to remember that God is not a being who could ever love us back. "He who loves God cannot strive that God should love him in return", says Spinoza (5p19).

Steven Nadler suggests that settling the question of Spinoza's atheism or pantheism depends on an analysis of attitudes. If pantheism is associated with religiosity, then Spinoza is not a pantheist, since Spinoza believes that the proper stance to take towards God is not one of reverence or religious awe, but instead one of objective study and reason, since taking the religious stance would leave one open to the possibility of error and superstition.

Other philosophical connections
Many authors have discussed similarities between Spinoza's philosophy and Eastern philosophical traditions. Few decades after the philosopher's death, Pierre Bayle, in his famous Historical and Critical Dictionary (1697) pointed out a link between Spinoza's alleged atheism with "the theology of a Chinese sect", supposedly called "Foe Kiao", of which had learned thanks to the testimonies of the Jesuit missions in Eastern Asia. A century later, Kant also established a parallel between the philosophy of Spinoza and the think of Laozi (a "monstrous system" in his words), grouping both under the name of pantheists, criticizing what he described as mystical tendencies in them.

In 1863, Elijah Benamozegh purported to establish that the main source of Spinoza's ontology is Kabbalah. The most recent research in the field seems to vindicate that claim.

The 19th-century German Sanskritist Theodor Goldstücker was one of the early figures to notice the similarities between Spinoza's religious conceptions and the Vedanta tradition of India, writing that Spinoza's thought was "... so exact a representation of the ideas of the Vedanta, that we might have suspected its founder to have borrowed the fundamental principles of his system from the Hindus, did his biography not satisfy us that he was wholly unacquainted with their doctrines..." Max Müller also noted the striking similarities between Vedanta and the system of Spinoza, equating the Brahman in Vedanta to Spinoza's 'Substantia.'

Legacy
Spinoza's ideas have had a major impact on intellectual debates from the seventeenth century to the current era. How Spinoza is viewed has gone from the atheistic author of treatises that undermine Judaism and organized religion, to a cultural hero, the first secular Jew. One writer contends that what draws readers to Spinoza today and "makes him perhaps the most beloved philosopher since Socrates, is his confident equanimity". He is not a despairing nihilist, but rather Spinoza says that "blessedness is nothing else but the contentment of spirit, which arises from the intuitive knowledge of God." One of his biographers, Jonathan I. Israel, argues that "No leading figure of the post-1750 later Enlightenment, for example, or the nineteenth century, was engaged with the philosophy of Descartes, Hobbes, Bayle, Locke, or Leibniz, to the degree leading figures such as Lessing, Goethe, Kant, Hegel, Fichte, Schelling, Heine, George Eliot, and Nietzsche, remained preoccupied throughout their creative lives with Spinoza." Hegel (1770-1831) asserts that "The fact is that Spinoza is made a testing-point in modern philosophy, so that it may really be said: You are either a Spinozist or not a philosopher at all."

His expulsion from the Portuguese synagogue in 1656 has stirred debate over the years on whether he is the "first modern Jew". Spinoza influenced discussions of the so-called Jewish question, the examination of the idea of Judaism and the modern, secular Jew. Moses Mendelsohn, Lessing, Heine, and Kant, as well as subsequent thinkers, including Marx, Nietzsche, and Freud were influenced by Spinoza. The changing conception of Spinoza as "the First Modern Jew" has been explicitly explored by various authors. His expulsion has been revisited in the 21st century, with Jewish writers such Berthold Auerbach; Salomon Rubin, who translated Spinoza's Ethics into Hebrew and saw Spinoza as a new Maimonides, penning "a new guide to the perplexed"; Zionist Yosef Klausner, and fiction-writer Isaac Bashevis Singer shaping his image.

In 1886, the young George Santayana published "The Ethical Doctrine of Spinoza", in The Harvard Monthly. Much later, he wrote an introduction to Spinoza's Ethics and "De Intellectus Emendatione". In 1932, Santayana was invited to present an essay (published as "Ultimate Religion") at a meeting at The Hague celebrating the tricentennial of Spinoza's birth. In Santayana's autobiography, he characterized Spinoza as his "master and model" in understanding the naturalistic basis of morality.

Philosopher Ludwig Wittgenstein evoked Spinoza with the title (suggested to him by G. E. Moore) of the English translation of his first definitive philosophical work, Tractatus Logico-Philosophicus, an allusion to Spinoza's Tractatus Theologico-Politicus. Elsewhere, Wittgenstein deliberately borrowed the expression sub specie aeternitatis from Spinoza (Notebooks, 1914–16, p. 83). The structure of his Tractatus Logico-Philosophicus does have some structural affinities with Spinoza's Ethics (though, admittedly, not with the Spinoza's Tractatus) in erecting complex philosophical arguments upon basic logical propositions and principles. In propositions 6.4311 and 6.45 he alludes to a Spinozian understanding of eternity and interpretation of the religious concept of eternal life, contending, "If by eternity is understood not eternal temporal duration, but timelessness, then he lives eternally who lives in the present." (6.4311) "The contemplation of the world sub specie aeterni is its contemplation as a limited whole." (6.45)

Spinoza's philosophy played an important role in the development of post-war French philosophy. Many of these philosophers "used Spinoza to erect a bulwark against the nominally irrationalist tendencies of phenomenology", which was associated with the dominance of Hegel, Martin Heidegger, and Edmund Husserl in France at that time. Louis Althusser, as well as his colleagues such as Étienne Balibar, saw in Spinoza a philosophy which could lead Marxism out of what they considered to be flaws in its original formulation, particularly its reliance upon Hegel's conception of the dialectic, as well as Spinoza's concept of immanent causality. Antonio Negri, in exile in France for much of this period, also wrote a number of books on Spinoza, most notably The Savage Anomaly (1981) in his own reconfiguration of Italian Autonomia Operaia. Other notable French scholars of Spinoza in this period included Alexandre Matheron, Martial Gueroult, André Tosel, and Pierre Macherey, the last of whom published a widely read and influential five-volume commentary on Spinoza's Ethics, which has been described as "a monument of Spinoza commentary". His philosophical accomplishments and moral character prompted Gilles Deleuze in his doctoral thesis (1968) to name him "the prince of philosophers". Deleuze's interpretation of Spinoza's philosophy was highly influential among French philosophers, especially in restoring to prominence the political dimension of Spinoza's thought. Deleuze published two books on Spinoza and gave numerous lectures on Spinoza in his capacity as a professor at the University of Paris VIII. His own work was deeply influenced by Spinoza's philosophy, particularly the concepts of immanence and univocity. Marilena de Souza Chaui described Deleuze's Expressionism in Philosophy (1968) as a "revolutionary work for its discovery of expression as a central concept in Spinoza's philosophy." Albert Einstein named Spinoza as the philosopher who exerted the most influence on his world view (Weltanschauung). Spinoza equated God (infinite substance) with Nature, consistent with Einstein's belief in an impersonal deity. In 1929, Einstein was asked in a telegram by Rabbi Herbert S. Goldstein whether he believed in God. Einstein responded by telegram: "I believe in Spinoza's God who reveals himself in the orderly harmony of what exists, not in a God who concerns himself with the fates and actions of human beings." Einstein wrote the preface to a biography of Spinoza, published in 1946.

Leo Strauss dedicated his first book, Spinoza's Critique of Religion, to an examination of his ideas. Strauss identified Spinoza as part of the tradition of Enlightenment rationalism that eventually produced Modernity. Moreover, he identifies Spinoza and his works as the beginning of Jewish Modernity. More recently Jonathan Israel argued that, from 1650 to 1750, Spinoza was "the chief challenger of the fundamentals of revealed religion, received ideas, tradition, morality, and what was everywhere regarded, in absolutist and non-absolutist states alike, as divinely constituted political authority."

Spinoza is an important historical figure in the Netherlands, where his portrait was featured prominently on the Dutch 1000-guilder banknote, legal tender until the euro was introduced in 2002. The highest and most prestigious scientific award of the Netherlands is named the Spinozaprijs (Spinoza prize). Spinoza was included in a 50 theme canon that attempts to summarise the history of the Netherlands. In 2014 a copy of Spinoza's Tractatus Theologico-Politicus was presented to the Chair of the Dutch Parliament, and shares a shelf with the Bible and the Quran.

Reconsideration of Spinoza's expulsion
There has been a renewed debate in modern times about Spinoza's excommunication among Israeli politicians, rabbis and Jewish press, with many calling for the cherem to be reversed. A conference was organized at the YIVO Institute for Jewish Research in New York entitled "From Heretic to Hero: A Symposium on the Impact of Baruch Spinoza on the 350th Anniversary of His Excommunication, 1656-2006". Presenters included Steven Nadler, Jonathan I. Israel, Steven B. Smith, and Daniel B. Schwartz. There have been calls for Spinoza's cherem to be rescinded, but it can only be done by the congregation that issued it, and the chief rabbi of that community, Haham Pinchas Toledano, declined to do so, citing Spinoza's "preposterous ideas, where he was tearing apart the very fundamentals of our religion", the Amsterdam Jewish community organised a symposium in December 2015 to discuss lifting the cherem, inviting scholars from around the world to form an advisory committee at the meeting. However, the rabbi of the congregation ruled that it should hold, on the basis that he had no greater wisdom than his predecessors, and that Spinoza's views had not become less problematic over time.

Memory and memorials

 * Spinoza Lyceum, a high school in Amsterdam South was named after Spinoza. There is also a 3 metre tall marble statue of him on the grounds of the school carved by Hildo Krop.
 * The Spinoza Havurah (a Humanistic Jewish community) was named in Spinoza's honor.
 * The Spinoza Foundation Monument has a statute of Spinoza located in front of the Amsterdam City Hall (at Zwanenburgwal) It was created by Dutch sculptor Nicolas Dings and was erected in 2008.

Depictions and influence in literature
Spinoza's life and work have been the subject of interest for several writers. For example, this influence was considerably early in German literature, where Goethe makes a glowing mention of the philosopher in his memoirs, highlighting the positive influence of the Ethics in his personal life. The same thing happened in the case of his compatriot, the poet Heine, who is also lavish in praise for Spinoza on his On the History of Religion and Philosophy in Germany (1834).

In the following century, the Argentinian Jorge Luis Borges famously wrote two sonnets in his honor ("Spinoza" in El otro, el mismo, 1964; and "Baruch Spinoza" in La moneda de hierro, 1976), and several direct references to Spinoza's philosophy can be found in this writer's work. Also in Argentina and previously to Borges, the Ukrainian-born Jewish intellectual Alberto Gerchunoff wrote a novella about philosopher's early sentimental life, Los amores de Baruj [sic] Spinoza (lit. "The loves of Baruj Spinoza", 1932), recreating a supposed affair or romantic interest with Clara Maria van den Enden, daughter of his Latin teacher and philosophical preceptor, Franciscus.

That is not the only work of fiction where the philosopher appears as the main character. In 1837 the German writer Berthold Auerbach dedicated to him the first novel in his series on Jewish history, translated into English in 1882 (Spinoza: a Novel). Some other novels of biographical nature have appeared more recently, such as The Spinoza Problem (2012; a parallel story between the philosopher's formative years, and the fascination that his work had on the Nazi leader Alfred Rosenberg) by psychiatrist Irvin D. Yalom, or O Segredo de Espinosa (lit. "The Secret of Spinoza", 2023) by Portuguese journalist José Rodrigues dos Santos. Spinoza also appears in the first novel of the Argentinian activist Andres Spokoiny, El impío (lit. "The Impious", 2021), about the marrano physician and philosopher Juan de Prado, a key influence in Spinoza's biography.

Original Editions

 * c. 1660. Korte Verhandeling van God, de mensch en deszelvs welstand (unpublished until the 19th century; A Short Treatise on God, Man and His Well-Being; translated by A. Wolf. London, Adam and Charles Black Eds., 1910).
 * 1662. Tractatus de Intellectus Emendatione (On the Improvement of the Understanding) (unfinished).
 * 1663. Principia philosophiae cartesianae (The Principles of Cartesian Philosophy, also contains Metaphysical Thoughts/Cogitata Metaphisica; translated by Samuel Shirley, with an Introduction and Notes by Steven Barbone and Lee Rice, Indianapolis, 1998).
 * 1670. Tractatus Theologico-Politicus (A Theologico-Political Treatise), TTP, published anonymously in his lifetime with a false place of publication.
 * 1675–76. Tractatus Politicus (Political Treatise), TP (unfinished at his death), published posthumously.
 * 1677. Ethica Ordine Geometrico Demonstrata (The Ethics, finished 1674, but published posthumously, title added posthumously).
 * 1677. Compendium grammatices linguae hebraeae (Hebrew Grammar, unfinished; translated with introduction by M. J. Bloom, London, 1963).
 * 1677. Epistolae (The Letters, translated by Samuel Shirley, with an Introduction and Notes by S. Barbone, L. Rice and J. Adler, Indianapolis, 1995).
 * Last four were originally collected and published by Spinoza's friends briefly later his death, in: B. d. S. Opera Posthuma, Quorum series post Praefationem exhibetur. (Amsterdam: Jan Rieuwertsz, 1677; both publisher and place were purposely omitted). Simultaneously, Rieuwertsz also published a Dutch translation by Jan Hendriksz Glazemaker (who some years later translated the TTP): De Nagelate Schriften van B. d. S., without the Hebrew Grammar.

Contemporary Editions

 * Shirley, Samuel (2002). Morgan, Michael L. (ed.). Spinoza Complete Works, with the Translations by Samuel Shirley. Indianapolis: Hackett Publishing Company. ISBN 978-0-87220-620-5. OCLC 49775415.
 * Edwin Curley (ed.), 1985, 2016. The Collected Works of Spinoza (two volumes), Princeton: Princeton University Press.(Excludes the Compendium grammatices linguae hebraeae).
 * Spruit, Leen and Pina Totaro, 2011. The Vatican Manuscript of Spinoza's Ethica, Leiden: Brill. This is the only known surviving manuscript of Spinoza's Ethics, discovered in the Vatican archive and published in a bilingual Latin-English edition.

Other works

 * Damásio, António, 2003. Looking for Spinoza: Joy, Sorrow, and the Feeling Brain, Harvest Books, ISBN 978-0-15-602871-4
 * Della Rocca, Michael. 1996. Representation and the Mind-Body Problem in Spinoza. Oxford University Press. ISBN 978-0-19-509562-3
 * Garrett, Don, ed., 1995. The Cambridge Companion to Spinoza. Cambridge Uni. Press.
 * Deleuze, Gilles, 1968. Spinoza et le problème de l'expression. Trans. "Expressionism in Philosophy: Spinoza" Martin Joughin (New York: Zone Books).
 * _____, 1970. Spinoza: Philosophie pratique. Transl. "Spinoza: Practical Philosophy".
 * _____, 1990. Negotiations trans. Martin Joughin (New York: Columbia University Press).
 * Gatens, Moira, and Lloyd, Genevieve, 1999. Collective imaginings: Spinoza, past and present. Routledge. ISBN 978-0-415-16570-9
 * Koistinen, Olli, (ed.). 2009. The Cambridge Companion to Spinoza's Ethics. Cambridge: Cambridge University Press.
 * Goode, Francis, 2012. Life of Spinoza. Smashwords edition. ISBN 978-1-4661-3399-0
 * Hampshire, Stuart, 1951. Spinoza and Spinozism, OUP, 2005 ISBN 978-0-19-927954-8
 * Hardt, Michael, trans., University of Minnesota Press. Preface, in French, by Gilles Deleuze, available here:
 * _____, 2006. Enlightenment Contested: Philosophy, Modernity, and the Emancipation of Man 1670–1752, (ISBN 978-0-19-927922-7)
 * _____. 2002. “Philosophy, Commerce and the Synagogue: Spinoza's Expulsion from the Amsterdam Portuguese Jewish Community in 1656.” In Dutch Jewry: Its History and Secular Culture (1500-2000). Edited by Jonathan Israel and Reinier Salverda, pp. 125–140. Leiden: Brill.
 * Kayser, Rudolf, 1946, with an introduction by Albert Einstein. Spinoza: Portrait of a Spiritual Hero. New York: The Philosophical Library.
 * Kisner, Matthew J. 2011. Spinoza on human freedom: Reason, autonomy and the good life. New York: Cambridge University Press.
 * Lloyd, Genevieve. 1994. Part of Nature: Self-Knowledge in Spinoza's 'Ethics'. Ithaca: Cornell University Press.
 * Lloyd, Genevieve. 2018. Reclaiming wonder. After the sublime. Edinburgh University Press. ISBN 978-1-4744-3311-2
 * LeBuffe, Michael. 2010. Spinoza and Human Freedom. Oxford University Press.
 * Lovejoy, Arthur O., 1936. "Plenitude and Sufficient Reason in Leibniz and Spinoza" in his The Great Chain of Being. Harvard University Press: 144–82 (ISBN 978-0-674-36153-9). Reprinted in Frankfurt, H. G., ed., 1972. Leibniz: A Collection of Critical Essays. Anchor Books.
 * Macherey, Pierre, 1977. Hegel ou Spinoza, Maspéro (2nd ed. La Découverte, 2004).
 * _____, 1994–98. Introduction à l'Ethique de Spinoza. Paris: PUF.
 * Magnusson 1990: Magnusson, M (ed.), Spinoza, Baruch, Chambers Biographical Dictionary, Chambers 1990, ISBN 978-0-550-16041-6.
 * Matheron, Alexandre, 1969. Individu et communauté chez Spinoza, Paris: Minuit.
 * Millner, Simon L., The Face of Benedictus Spinoza (New York: Machmadim Art Editions, Inc., 1946).
 * Montag, Warren, Bodies, Masses, Power: Spinoza and his Contemporaries. (London: Verso, 2002).
 * Moreau, Pierre-François, 2003, Spinoza et le spinozisme, PUF (Presses Universitaires de France)
 * Nadler, Steven, Think Least of Death: Spinoza on How to Live and How to Die, 2020 (Princeton, New Jersey: Princeton University Press, ISBN 978-0691183848).
 * Negri, Antonio, 1991. The Savage Anomaly: The Power of Spinoza's Metaphysics and Politics.
 * _____, 2004. Subversive Spinoza: (Un)Contemporary Variations.
 * Ratner, Joseph, 1927. The Philosophy of Spinoza (The Modern Library: Random House)
 * Stolze, Ted and Warren Montag (eds.), The New Spinoza, Minneapolis: University of Minnesota Press, 1997.
 * Strauss, Leo. Persecution and the Art of Writing. Glencoe, Illinois: Free Press, 1952. Reprint. Chicago: University of Chicago Press, 1988.
 * _____ch. 5, "How to Study Spinoza's Tractus Theologico-Politicus;" reprinted in Strauss, Jewish Philosophy and the Crisis of Modernity, ed. Kenneth Hart Green (Albany, NY: SUNY Press, 1997), 181–233.
 * ____Spinoza's Critique of Religion. New York: Schocken Books, 1965. Reprint. University of Chicago Press, 1996.
 * _____ "Preface to the English Translation" reprinted as "Preface to Spinoza's Critique of Religion", in Strauss, Liberalism Ancient and Modern (New York: Basic Books, 1968, 224–59; also in Strauss, Jewish Philosophy and the Crisis of Modernity, 137–77).
 * Valentiner, W.R., 1957. Rembrandt and Spinoza: A Study of the Spiritual Conflicts in Seventeenth-Century Holland, London: Phaidon Press.
 * Vinciguerra, Lorenzo Spinoza in French Philosophy Today. Philosophy Today, Vol. 53, No. 4, Winter 2009.
 * Van den Ven, Jeroen. Printing Spinoza: A Descriptive Bibliography of the Works Published in the Seventeenth Century. Leiden 2022.
 * _____. Documenting Spinoza: A Biographical History of his Life and Time. (forthcoming)
 * Williams, David Lay. 2010. "Spinoza and the General Will", The Journal of Politics, vol. 72 (April): 341–356.
 * Wolfson, Henry A. "The Philosophy of Spinoza". 2 vols. Harvard University Press.
 * Williams, David Lay. 2010. "Spinoza and the General Will", The Journal of Politics, vol. 72 (April): 341–356.
 * Wolfson, Henry A. "The Philosophy of Spinoza". 2 vols. Harvard University Press.

title: Baruch Spinoza