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Cosmological argument

A cosmological argument, in natural theology, is an argument which claims that the existence of God can be inferred from facts concerning causation, explanation, change, motion, contingency, dependency, or finitude with respect to the universe or some totality of objects. A cosmological argument can also sometimes be referred to as an argument from universal causation, an argument from first cause, the causal argument, or the prime mover argument. Whichever term is employed, there are two basic variants of the argument, each with subtle yet important distinctions: in esse (essentiality), and in fieri (becoming).

The basic premises of all of these arguments involve the concept of causation. The conclusion of these arguments is that there exists a first cause, subsequently analysed to be God. The history of this argument goes back to Aristotle or earlier, was developed in Neoplatonism and early Christianity and later in medieval Islamic theology during the 9th to 12th centuries, and was re-introduced to medieval Christian theology in the 13th century by Thomas Aquinas. The cosmological argument is closely related to the principle of sufficient reason as addressed by Gottfried Leibniz and Samuel Clarke, itself a modern exposition of the claim that "nothing comes from nothing" attributed to Parmenides. Contemporary defenders of cosmological arguments include William Lane Craig, Robert Koons, John Lennox, Stephen Meyer, and Alexander Pruss.

History

Plato (c. 427–347 BC) and Aristotle (c. 384–322 BC) both posited first cause arguments, though each had certain notable caveats. In The Laws (Book X), Plato posited that all movement in the world and the Cosmos was "imparted motion". This required a "self-originated motion" to set it in motion and to maintain it. In Timaeus, Plato posited a "demiurge" of supreme wisdom and intelligence as the creator of the Cosmos.

Aristotle argued against the idea of a first cause, often confused with the idea of a "prime mover" or "unmoved mover" (πρῶτον κινοῦν ἀκίνητον or primus motor) in his Physics and Metaphysics. Aristotle argued in favor of the idea of several unmoved movers, one powering each celestial sphere, which he believed lived beyond the sphere of the fixed stars, and explained why motion in the universe (which he believed was eternal) had continued for an infinite period of time. Aristotle argued the atomist's assertion of a non-eternal universe would require a first uncaused cause – in his terminology, an efficient first cause – an idea he considered a nonsensical flaw in the reasoning of the atomists.

Like Plato, Aristotle believed in an eternal cosmos with no beginning and no end (which in turn follows Parmenides' famous statement that "nothing comes from nothing"). In what he called "first philosophy" or metaphysics, Aristotle did intend a theological correspondence between the prime mover and a deity; functionally, however, he provided an explanation for the apparent motion of the "fixed stars" (now understood as the daily rotation of the Earth). According to his theses, immaterial unmoved movers are eternal unchangeable beings that constantly think about thinking, but being immaterial, they are incapable of interacting with the cosmos and have no knowledge of what transpires therein. From an "aspiration or desire", the celestial spheres, imitate that purely intellectual activity as best they can, by uniform circular motion. The unmoved movers inspiring the planetary spheres are no different in kind from the prime mover, they merely suffer a dependency of relation to the prime mover. Correspondingly, the motions of the planets are subordinate to the motion inspired by the prime mover in the sphere of fixed stars. Aristotle's natural theology admitted no creation or capriciousness from the immortal pantheon, but maintained a defense against dangerous charges of impiety.

Plotinus, a third-century Platonist, taught that the One transcendent absolute caused the universe to exist simply as a consequence of its existence (creatio ex deo). His disciple Proclus stated "The One is God". Centuries later, the Islamic philosopher Avicenna (c. 980–1037) inquired into the question of being, in which he distinguished between essence (māhiyya) and existence (wuǧūd). He argued that the fact of existence could not be inferred from or accounted for by the essence of existing things, and that form and matter by themselves could not originate and interact with the movement of the Universe or the progressive actualization of existing things. Thus, he reasoned that existence must be due to an agent cause that necessitates, imparts, gives, or adds existence to an essence. To do so, the cause must coexist with its effect and be an existing thing.

Steven Duncan writes that it "was first formulated by a Greek-speaking Syriac Christian neo-Platonist, John Philoponus, who claims to find a contradiction between the Greek pagan insistence on the eternity of the world and the Aristotelian rejection of the existence of any actual infinite". Referring to the argument as the "'Kalam' cosmological argument", Duncan asserts that it "received its fullest articulation at the hands of [medieval] Muslim and Jewish exponents of Kalam ("the use of reason by believers to justify the basic metaphysical presuppositions of the faith").

Thomas Aquinas (c. 1225–1274) adapted and enhanced the argument he found in his reading of Aristotle, Avicenna (the Proof of the Truthful), and Maimonides to form one of the most influential versions of the cosmological argument. His conception of first cause was the idea that the Universe must be caused by something that is itself uncaused, which he claimed is that which we call God:

"The second way is from the nature of the efficient cause. In the world of sense we find there is an order of efficient causes. There is no case known (neither is it, indeed, possible) in which a thing is found to be the efficient cause of itself; for so it would be prior to itself, which is impossible. Now in efficient causes it is not possible to go on to infinity, because in all efficient causes following in order, the first is the cause of the intermediate cause, and the intermediate is the cause of the ultimate cause, whether the intermediate cause be several, or only one. Now to take away the cause is to take away the effect. Therefore, if there be no first cause among efficient causes, there will be no ultimate, nor any intermediate cause. But if in efficient causes it is possible to go on to infinity, there will be no first efficient cause, neither will there be an ultimate effect, nor any intermediate efficient causes; all of which is plainly false. Therefore it is necessary to admit a first efficient cause, to which everyone gives the name of God."

Importantly, Aquinas' Five Ways, given the second question of his Summa Theologica, are not the entirety of Aquinas' demonstration that the Christian God exists. The Five Ways form only the beginning of Aquinas' Treatise on the Divine Nature.

Argument from contingency
In the scholastic era, Aquinas formulated the "argument from contingency", following Aristotle in claiming that there must be something to explain why the Universe exists. Since the Universe could, under different circumstances, conceivably not exist (contingency), its existence must have a cause – not merely another contingent thing, but something that exists by necessity (something that must exist in order for anything else to exist). In other words, even if the Universe has always existed, it still owes its continuing existence to an uncaused cause, Aquinas further said: "... and this we understand to be God."

Aquinas's argument from contingency allows for the possibility of a Universe that has no beginning in time. It is a form of argument from universal causation. Aquinas observed that, in nature, there were things with contingent existences. Since it is possible for such things not to exist, there must be some time at which these things did not in fact exist. Thus, according to Aquinas, there must have been a time when nothing existed. If this is so, there would exist nothing that could bring anything into existence. Contingent beings, therefore, are insufficient to account for the existence of contingent beings: there must exist a necessary being whose non-existence is an impossibility, and from which the existence of all contingent beings is ultimately derived.

Aquinas' argument from contingency may also be formulated like this: if each contingently existing being considers himself Bn, then, because he exists contingently, he depends for his existence on a prior being Bn-1. Now, Bn-1 likewise, if it is contingent, depends on Bn-2. Nevertheless, this series cannot go on until Infinity. At a certain time, we will arrive at a B1, the First Being in existence, and since there is no "zeroth" Being or B0, B1 exists Necessarily, i.e. is not a contingent being. This was Aquinas' Third Way, under Question 2, Article 3 in the Summa Theologica

The German philosopher Gottfried Leibniz made a similar argument with his principle of sufficient reason in 1714. "There can be found no fact that is true or existent, or any true proposition," he wrote, "without there being a sufficient reason for its being so and not otherwise, although we cannot know these reasons in most cases." He formulated the cosmological argument succinctly: "Why is there something rather than nothing? The sufficient reason ... is found in a substance which ... is a necessary being bearing the reason for its existence within itself."

Leibniz's argument from contingency is one of the most popular cosmological arguments in philosophy of religion. It attempts to prove the existence of a necessary being and infer that this being is God. Alexander Pruss formulates the argument as follows:

 * 1) Every contingent fact has an explanation.
 * 2) There is a contingent fact that includes all other contingent facts.
 * 3) Therefore, there is an explanation of this fact.
 * 4) This explanation must involve a necessary being.
 * 5) This necessary being is God.

Premise 1 is a form of the principle of sufficient reason stating that all contingently true sentences (i.e. contingent facts) have a sufficient explanation as to why they are the case. Premise 2 refers to what is known as the Big Conjunctive Contingent Fact (abbreviated BCCF), and the BCCF is generally taken to be the logical conjunction of all contingent facts. It can be thought about as the sum total of all contingent reality. Premise 3 then concludes that the BCCF has an explanation, as every contingency does (in virtue of the PSR). It follows that this explanation is non-contingent (i.e. necessary); no contingency can explain the BCCF, because every contingent fact is a part of the BCCF. Statement 5, which is either seen as a premise or a conclusion, infers that the necessary being which explains the totality of contingent facts is God. Several philosophers of religion, such as Joshua Rasmussen and T. Ryan Byerly, have argued for the inference from (4) to (5).

In esse and in fieri
The difference between the arguments from causation in fieri and in esse is a fairly important one. In fieri is generally translated as "becoming", while in esse is generally translated as "in essence". In fieri, the process of becoming, is similar to building a house. Once it is built, the builder walks away, and it stands on its own accord; compare the watchmaker analogy. (It may require occasional maintenance, but that is beyond the scope of the first cause argument.)

In esse (essence) is more akin to the light from a candle or the liquid in a vessel. George Hayward Joyce, SJ, explained that, "where the light of the candle is dependent on the candle's continued existence, not only does a candle produce light in a room in the first instance, but its continued presence is necessary if the illumination is to continue. If it is removed, the light ceases. Again, a liquid receives its shape from the vessel in which it is contained; but were the pressure of the containing sides withdrawn, it would not retain its form for an instant." This form of the argument is far more difficult to separate from a purely first cause argument than is the example of the house's maintenance above, because here the first cause is insufficient without the candle's or vessel's continued existence.

The philosopher Robert Koons has stated a new variant on the cosmological argument. He says that to deny causation is to deny all empirical ideas – for example, if we know our own hand, we know it because of the chain of causes including light being reflected upon one's eyes, stimulating the retina and sending a message through the optic nerve into your brain. He summarised the purpose of the argument as "that if you don't buy into theistic metaphysics, you're undermining empirical science. The two grew up together historically and are culturally and philosophically inter-dependent ... If you say I just don't buy this causality principle – that's going to be a big big problem for empirical science." This in fieri version of the argument therefore does not intend to prove God, but only to disprove objections involving science, and the idea that contemporary knowledge disproves the cosmological argument.

Kalām cosmological argument
William Lane Craig, who was principally responsible for re-popularizing this argument in Western philosophy, presents it in the following general form:
 * 1) Whatever begins to exist has a cause of its existence.
 * 2) The universe began to exist.
 * 3) Therefore, the universe has a cause of its existence.

Craig analyses this cause in The Blackwell Companion to Natural Theology and says that this cause must be uncaused, beginningless, changeless, timeless, spaceless, extraordinarily powerful, and personal.

Metaphysical argument for the existence of God
Duns Scotus, the influential Medieval Christian theologian, created a metaphysical argument for the existence of God. Though it was inspired by Aquinas' argument from motion, he, like other philosophers and theologians, believed that his statement for God's existence could be considered separate to Aquinas'. His explanation for God's existence is long, and can be summarised as follows:
 * 1) Something can be produced.
 * 2) It is produced by itself, by nothing, or by another.
 * 3) Not by nothing, because nothing causes nothing.
 * 4) Not by itself, because an effect never causes itself.
 * 5) Therefore, by another A.
 * 6) If A is first then we have reached the conclusion.
 * 7) If A is not first, then we return to 2).
 * 8) From 3) and 4), we produce another- B. The ascending series is either infinite or finite.
 * 9) An infinite series is not possible.
 * 10) Therefore, God exists.

Scotus deals immediately with two objections he can see: first, that there cannot be a first, and second, that the argument falls apart when 1) is questioned. He states that infinite regress is impossible, because it provokes unanswerable questions, like, in modern English, "What is infinity minus infinity?" The second he states can be answered if the question is rephrased using modal logic, meaning that the first statement is instead "It is possible that something can be produced."

Cosmological argument and infinite regress
Depending on its formulation, the cosmological argument is an example of a positive infinite regress argument. An infinite regress is an infinite series of entities governed by a recursive principle that determines how each entity in the series depends on or is produced by its predecessor. An infinite regress argument is an argument against a theory based on the fact that this theory leads to an infinite regress. A positive infinite regress argument employs the regress in question to argue in support of a theory by showing that its alternative involves a vicious regress. The regress relevant for the cosmological argument is the regress of causes: an event occurred because it was caused by another event that occurred before it, which was itself caused by a previous event, and so on. For an infinite regress argument to be successful, it has to demonstrate not just that the theory in question entails an infinite regress but also that this regress is vicious. Once the viciousness of the regress of causes is established, the cosmological argument can proceed to its positive conclusion by holding that it is necessary to posit a first cause in order to avoid it.

A regress can be vicious due to metaphysical impossibility, implausibility or explanatory failure. It is sometimes held that the regress of causes is vicious because it is metaphysically impossible, i.e. that it involves an outright contradiction. But it is difficult to see where this contradiction lies unless an additional assumption is accepted: that actual infinity is impossible. But this position is opposed to infinity in general, not just specifically to the regress of causes. A more promising view is that the regress of causes is to be rejected because it is implausible. Such an argument can be based on empirical observation, e.g. that, to the best of our knowledge, our universe had a beginning in the form of the Big Bang (albeit the possibility that it existed for eternity before the Big Bang is also not strictly excluded on physics grounds alone ). But it can also be based on more abstract principles, like Ockham's razor (parsimony), which posits that we should avoid ontological extravagance by not multiplying entities without necessity. A third option is to see the regress of causes as vicious due to explanatory failure, i.e. that it does not solve the problem it was formulated to solve or that it assumes already in disguised form what it was supposed to explain. According to this position, we seek to explain one event in the present by citing an earlier event that caused it. But this explanation is incomplete unless we can come to understand why this earlier event occurred, which is itself explained by its own cause and so on. At each step, the occurrence of an event has to be assumed. So it fails to explain why anything at all occurs, why there is a chain of causes to begin with.

"What caused the first cause?"
One objection to the argument asks why a first cause is unique in that it does not require any causes. Proponents argue that the first cause is exempt from having a cause, as this is part of what it is to be the first cause, while opponents argue that this is special pleading or otherwise untrue. Critics often press that arguing for the first cause's exemption raises the question of why the first cause is indeed exempt, whereas defenders maintain that this question has been answered by the various arguments, emphasizing that none of the major cosmological arguments rests on the premise that everything has a cause, and so the question does not address the actual premises of an argument and rests on a misunderstanding of them.

William Lane Craig, who popularized and is notable for defending the Kalam cosmological argument, argues that the infinite is impossible, whichever perspective the viewer takes, and so there must always have been one unmoved thing to begin the universe. He uses Hilbert's paradox of the Grand Hotel and the question "What is infinity minus infinity?" to illustrate the idea that the infinite is metaphysically, mathematically, and even conceptually impossible. Other reasons include the fact that it is impossible to count down from infinity, and that, had the universe existed for an infinite amount of time, every possible event, including the final end of the universe, would already have occurred. He therefore states his argument in three points: firstly, everything that begins to exist has a cause of its existence; secondly, the universe began to exist; so, thirdly, therefore, the universe has a cause of its existence. Craig argues in the Blackwell Companion to Natural Theology that there cannot be an infinite regress of causes and thus there must be a first uncaused cause, even if one posits a plurality of causes of the universe. He argues Occam's razor may be employed to remove unneeded further causes of the universe to leave a single uncaused cause.

Secondly, it is argued that the premise of causality has been arrived at via a posteriori (inductive) reasoning, which is dependent on experience. David Hume highlighted this problem of induction and argued that causal relations were not true a priori. However, as to whether inductive or deductive reasoning is more valuable remains a matter of debate, with the general conclusion being that neither is prominent. Opponents of the argument tend to argue that it is unwise to draw conclusions from an extrapolation of causality beyond experience. Andrew Loke replies that, according to the Kalam cosmological argument, only things which begin to exist require a cause. On the other hand, something that is without beginning has always existed and therefore does not require a cause. The Kalam and the Thomistic cosmological argument posit that there cannot be an actual infinite regress of causes, therefore there must be an uncaused first cause that is beginningless and does not require a cause.

Not evidence for a theistic God
According to this objection, the basic cosmological argument merely establishes that a first cause exists, not that it has the attributes of a theistic god, such as omniscience, omnipotence, and omnibenevolence. This is why the argument is often expanded to assert that at least some of these attributes are necessarily true, for instance in the modern Kalam argument given above.

Defenders of the cosmological arguments also reply that theologians of note are aware of the need to additionally prove other attributes of the first cause beyond that one exists. One notable example of this is found in Aquinas' Summa Theologiae in which much of the first part (Prima Pars) is devoted to establishing the attributes of this first cause, such as its uniqueness, perfection, and intelligence. Thus defenders of cosmological arguments would reply that while it is true that the cosmological argument only establishes a first cause, this is merely the first step which then allows for the demonstration of the other theistic attributes.

Existence of causal loops
A causal loop is a form of predestination paradox arising where traveling backwards in time is deemed a possibility. A sufficiently powerful entity in such a world would have the capacity to travel backwards in time to a point before its own existence, and to then create itself, thereby initiating everything which follows from it. The usual reason given to refute the possibility of a causal loop is that it requires that the loop as a whole be its own cause. Richard Hanley argues that causal loops are not logically, physically, or epistemically impossible: "[In timed systems,] the only possibly objectionable feature that all causal loops share is that coincidence is required to explain them". However, Andrew Loke argues that causal loop of the type that is supposed to avoid a first cause suffers from the problem of vicious circularity and thus it would not work.

Existence of infinite causal chains
David Hume and later Paul Edwards have invoked a similar principle in their criticisms of the cosmological argument. William L. Rowe has called this the Hume-Edwards principle:

"If the existence of every member of a set is explained, the existence of that set is thereby explained."

Nevertheless, David White argues that the notion of an infinite causal regress providing a proper explanation is fallacious. Furthermore, in Hume's Dialogues Concerning Natural Religion, the character Demea states that even if the succession of causes is infinite, the whole chain still requires a cause. To explain this, suppose there exists a causal chain of infinite contingent beings. If one asks the question, "Why are there any contingent beings at all?", it does not help to be told that "There are contingent beings because other contingent beings caused them." That answer would just presuppose additional contingent beings. An adequate explanation of why some contingent beings exist would invoke a different sort of being, a necessary being that is not contingent. A response might suppose each individual is contingent but the infinite chain as a whole is not, or the whole infinite causal chain is its own cause.

Severinsen argues that there is an "infinite" and complex causal structure. White tried to introduce an argument "without appeal to the principle of sufficient reason and without denying the possibility of an infinite causal regress". A number of other arguments have been offered to demonstrate that an actual infinite regress cannot exist, viz. the argument for the impossibility of concrete actual infinities, the argument for the impossibility of traversing an actual infinite, the argument from the lack of capacity to begin to exist, and various arguments from paradoxes.

Other defenders of cosmological arguments such as Ed Feser argue that the type of series in which causes are hierarchically dependent (essentially ordered or per se series) one on the other, cannot regress to infinity, even if it may be possible for causal series which are extended backward through time (accidentally ordered or per accidens series) to regress infinitely. The rationale for this is that in a hierarchical per se causal series, each member cannot so much as act without the concurrent actualization or causation of more fundamental members of the series; thus an infinite hierarchical series would mean that the entire series is composed of members none of which can act of itself, which is impossible. An example of such a series would be the composition of water, which depends on the simultaneous composition of hydrogen and oxygen atoms, which in turn depend on the simultaneous composition of protons, neutrons, and electrons, etc. into deeper levels of the hierarchy of physical reality. This is contrasted with an accidentally ordered or linear series - parents causing their children to begin to exist, who in turn cause their children to begin to exist - in which one member in the series may continue to act even if whatever caused it has ceased to exist, and so there is seemingly no issue if this type of series regresses infinitely; the impossibility of the infinite regress in an essentially ordered causal series would suffice for at least some varieties of cosmological arguments. Further discussion on this point can be found under essential and accidental causal chains.

Big Bang cosmology
Some cosmologists and physicists, such as Carlo Rovelli, argue that a challenge to the cosmological argument is the nature of time: "One finds that time just disappears from the Wheeler–DeWitt equation." The Big Bang theory states that it is the point in which all dimensions came into existence, the start of both space and time. Then, the question "What was there before the Universe?" makes no sense; the concept of "before" becomes meaningless when considering a situation without time. This has been put forward by J. Richard Gott III, James E. Gunn, David N. Schramm, and Beatrice Tinsley, who said that asking what occurred before the Big Bang is like asking what is north of the North Pole. However, some cosmologists and physicists attempt to investigate causes for the Big Bang, using such scenarios as the collision of membranes. Philosopher Edward Feser argues that most of the classical philosophers' cosmological arguments for the existence of God do not depend on the Big Bang or whether the universe had a beginning. The question is not about what got things started, or how long they have been going, but rather what keeps them going.

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title: Cosmological argument


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Clutch

A clutch is a mechanical device that allows the output shaft to be disconnected from the rotating input shaft. The clutch's input shaft is typically attached to a motor, while the clutch's output shaft is connected to the mechanism that does the work.

In a motor vehicle, the clutch acts as a mechanical linkage between the engine and transmission. By disengaging the clutch, the engine speed (RPM) is no longer determined by the speed of the driven wheels.

Another example of clutch usage is in electric drills. The clutch's input shaft is driven by a motor and the output shaft is connected to the drill bit (via several intermediate components). The clutch allows the drill bit to either spin at the same speed as the motor (clutch engaged), spin at a lower speed as the motor (clutch slipping) or remain stationary while the motor is spinning (clutch disengaged).

Dry clutch
A dry clutch uses dry friction to transfer power from the input shaft to the output shaft, for example a friction disk pressing on a car engine's flywheel. The majority of clutches are dry clutches, especially in vehicles with manual transmissions. Slippage of a friction clutch (where the clutch is partially engaged but the shafts are rotating at different speeds) is sometimes required, such as when a motor vehicle accelerates from a standstill; however the slippage should be minimised to avoid increased wear rates.

In a pull-type clutch, pressing the pedal pulls the release bearing to disengage the clutch. In a push-type clutch, pressing the pedal pushes the release bearing to disengage the clutch.

A multi-plate clutch consists of several friction plates arranged concentrically. In some cases, it is used instead of a larger diameter clutch. Drag racing cars use multi-plate clutches to control the rate of power transfer to the wheels as the vehicle accelerates from a standing start.

Some clutch disks include springs designed to change the natural frequency of the clutch disc, in order to reduce NVH within the vehicle. Also, some clutches for manual transmission cars use a clutch delay valve to avoid abrupt engagements of the clutch.

Wet clutch
In a wet clutch, the friction material sits in an oil bath (or has flow-through oil) which cools and lubricates the clutch. This can provide smoother engagement and a longer lifespan of the clutch, however wet clutches can have a lower efficiency due to some energy being transferred to the oil. Since the surfaces of a wet clutch can be slippery (as with a motorcycle clutch bathed in engine oil), stacking multiple clutch discs can compensate for the lower coefficient of friction and so eliminate slippage under power when fully engaged.

Wet clutches often use a composite paper material.

Centrifugal clutch
A centrifugal clutch automatically engages as the speed of the input shaft increases and disengages as the input shaft speed decreases. Applications include small motorcycles, motor scooters, chainsaws, and some older automobiles.

Cone clutch
A cone clutch is similar to dry friction plate clutch, except the friction material is applied to the outside of a conical shaped object. A common application for cone clutches is the synchronizer ring in a manual transmission.

Dog clutch
A dog clutch is a non-slip design of clutch which is used in non-synchronous transmissions.

Single-revolution clutch

The single-revolution clutch was developed in the 19th century to power machinery such as shears or presses where a single pull of the operating lever or (later) press of a button would trip the mechanism, engaging the clutch between the power source and the machine's crankshaft for exactly one revolution before disengaging the clutch. When the clutch is disengaged, the driven member is stationary. Early designs were typically dog clutches with a cam on the driven member used to disengage the dogs at the appropriate point.

Greatly simplified single-revolution clutches were developed in the 20th century, requiring much smaller operating forces and in some variations, allowing for a fixed fraction of a revolution per operation. Fast action friction clutches replaced dog clutches in some applications, eliminating the problem of impact loading on the dogs every time the clutch engaged.

In addition to their use in heavy manufacturing equipment, single-revolution clutches were applied to numerous small machines. In tabulating machines, for example, pressing the operate key would trip a single revolution clutch to process the most recently entered number. In typesetting machines, pressing any key selected a particular character and also engaged a single rotation clutch to cycle the mechanism to typeset that character. Similarly, in teleprinters, the receipt of each character tripped a single-revolution clutch to operate one cycle of the print mechanism.

In 1928, Frederick G. Creed developed a single-turn wrap spring clutch that was particularly well suited to the repetitive start-stop action required in teleprinters. In 1942, two employees of Pitney Bowes Postage Meter Company developed an improved single turn spring clutch. In these clutches, a coil spring is wrapped around the driven shaft and held in an expanded configuration by the trip lever. When tripped, the spring rapidly contracts around the power shaft engaging the clutch. At the end of one revolution, if the trip lever has been reset, it catches the end of the spring (or a pawl attached to it), and the angular momentum of the driven member releases the tension on the spring. These clutches have long operating lives—many have performed tens and perhaps hundreds of millions of cycles without the need of maintenance other than occasional lubrication.

Cascaded-pawl single-revolution clutches superseded wrap-spring single-revolution clutches in page printers, such as teleprinters, including the Teletype Model 28 and its successors, using the same design principles. IBM Selectric typewriters also used them. These are typically disc-shaped assemblies mounted on the driven shaft. Inside the hollow disc-shaped drive drum are two or three freely floating pawls arranged so that when the clutch is tripped, the pawls spring outward much like the shoes in a drum brake. When engaged, the load torque on each pawl transfers to the others to keep them engaged. These clutches do not slip once locked up, and they engage very quickly, on the order of milliseconds. A trip projection extends out from the assembly. If the trip lever engaged this projection, the clutch was disengaged. When the trip lever releases this projection, internal springs and friction engage the clutch. The clutch then rotates one or more turns, stopping when the trip lever again engages the trip projection.

Other designs

 * Kickback clutch-brakes: Found in some types of synchronous-motor-driven electric clocks built before the 1940s, to prevent the clock from running backwards. The clutch consisted of a wrap-spring clutch-brake that was coupled to the rotor by one or two stages of reduction gearing. The clutch-brake locked up when rotated backwards, but also had some spring action. The inertia of the rotor going backwards engaged the clutch and wound the spring. As it unwound, it restarted the motor in the correct direction.
 * Belt clutch: used on agricultural equipment, lawnmowers, tillers, and snow blowers. Engine power is transmitted via a set of belts that are slack when the engine is idling, but an idler pulley can tighten the belts to increase friction between the belts and the pulleys.
 * BMA clutch: Invented by Waldo J Kelleigh in 1949, used for transmitting torque between two shafts consisting of a fixed driving member secured to one of said shafts, and a movable driving member, having a contacting surface with a plurality of indentations.
 * Electromagnetic clutch: typically engaged by an electromagnet that is an integral part of the clutch assembly. Another type, the magnetic particle clutch, contains magnetically influenced particles in a chamber between driving and driven members—application of direct current makes the particles clump together and adhere to the operating surfaces. Engagement and slippage are notably smooth.
 * Wrap-spring clutch: has a helical spring, typically wound with square-cross-section wire. These were developed in the late 19th and early 20th-century. In simple form the spring is fastened at one end to the driven member; its other end is unattached. The spring fits closely around a cylindrical driving member. If the driving member rotates in the direction that would unwind the spring expands minutely and slips although with some drag. Because of this, spring clutches must typically be lubricated with light oil. Rotating the driving member the other way makes the spring wrap itself tightly around the driving surface and the clutch locks up very quickly. The torque required to make a spring clutch slip grows exponentially with the number of turns in the spring, obeying the capstan equation.

Manual transmissions
Most cars and trucks with a manual transmission use a dry clutch, which is operated by the driver using the left-most pedal. The motion of the pedal is transferred to the clutch using hydraulics (master and slave cylinders) or a cable. The clutch is only disengaged at times when the driver is pressing on the clutch pedal, therefore the default state is for the transmission to be connected to the engine. A "neutral" gear position is provided, so that the clutch pedal can be released with the vehicle remaining stationary.

The clutch is required for standing starts and is usually (but not always) used to assist in synchronising the speeds of the engine and transmission during gear changes, i.e. while reducing the engine speed (RPM) during upshifts and increasing the engine speed during downshifts.

The clutch is usually mounted directly to the face of the engine's flywheel, as this already provides a convenient large-diameter steel disk that can act as one driving plate of the clutch. Some racing clutches use small multi-plate disk packs that are not part of the flywheel. Both clutch and flywheel are enclosed in a conical bellhousing for the gearbox. The friction material used for the clutch disk varies, with a common material being an organic compound resin with a copper wire facing or a ceramic material.

Automatic transmissions
In an automatic transmission, the role of the clutch is performed by a torque converter. However, the transmission itself often includes internal clutches, such as a lock-up clutch to prevent slippage of the torque converter, in order to reduce the energy loss through the transmission and therefore improve fuel economy.

Fans and compressors
Older belt-driven engine cooling fans often use a heat-activated clutch, in the form of a bimetallic strip. When the temperature is low, the spring winds and closes the valve, which lets the fan spin at about 20% to 30% of the crankshaft speed. As the temperature of the spring rises, it unwinds and opens the valve, allowing fluid past the valve, making the fan spin at about 60% to 90% of crankshaft speed.

A vehicle's air-conditioning compressor often uses magnetic clutches to engage the compressor as required.

Usage in motorcycles

Motorcycles typically employ a wet clutch with the clutch riding in the same oil as the transmission. These clutches are usually made up of a stack of alternating friction plates and steel plates. The friction plates have lugs on their outer diameters that lock them into a basket that is turned by the crankshaft. The steel plates have lugs on their inner diameters that lock them to the transmission input shaft. A set of coil springs or a diaphragm spring plate force the plates together when the clutch is engaged.

On motorcycles the clutch is operated by a hand lever on the left handlebar. No pressure on the lever means that the clutch plates are engaged (driving), while pulling the lever back towards the rider disengages the clutch plates through cable or hydraulic actuation, allowing the rider to shift gears or coast. Racing motorcycles often use slipper clutches to eliminate the effects of engine braking, which, being applied only to the rear wheel, can cause instability.

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Cow tipping

Cow tipping is the purported activity of sneaking up on any unsuspecting or sleeping upright cow and pushing it over for entertainment. The practice of cow tipping is generally considered an urban legend and stories of such feats viewed as tall tales. The implication that rural citizens seek such entertainment due to lack of alternatives is viewed as a stereotype. The concept of cow tipping apparently developed in the 1970s, though tales of animals that cannot rise if they fall has historical antecedents dating to the Roman Empire.

Cows routinely lie down and can easily regain their footing unless sick or injured. Scientific studies have been conducted to determine if cow tipping is theoretically possible, with varying conclusions. All agree that cows are large animals that are difficult to surprise and will generally resist attempts to be tipped. Estimates suggest a force of between 3000 and 4000 N is needed, and that at least four and possibly as many as fourteen people would be required to achieve this. In real-life situations where cattle have to be laid on the ground, or "cast", such as for branding, hoof care or veterinary treatment, either rope restraints are required or specialized mechanical equipment is used that confines the cow and then tips it over. On rare occasions, cattle can lie down or fall down in proximity to a ditch or hill that restricts their normal ability to rise without help. Cow tipping has many references in popular culture and is also used as a figure of speech.

Scientific study
Some versions of the urban legend suggest that because cows sleep standing up, it is possible to approach them and push them over without the animals reacting. However, cows only sleep lightly while standing up, and they are easily awakened. They lie down to sleep deeply. Furthermore, numerous sources have questioned the practice's feasibility, since most cows weigh over 450 kg and easily resist any lesser force.

A 2005 study led by Margo Lillie, a zoologist at the University of British Columbia, and her student Tracy Boechler, concluded that tipping a cow would require a force of nearly 3000 N and is therefore impossible to accomplish by a single person. Her calculations found that it would require more than four people to apply enough force to push over a cow, based on an estimate that a single person could exert 660 N of force. However, since a cow can brace itself, Lillie and Boechler suggested that five or six people would, most likely, be needed. Further, cattle are well aware of their surroundings and are very difficult to surprise, due to excellent senses of both smell and hearing. Lillie and Boechler's analysis found that if a cow did not move, the principles of static physics suggest that two people might be able to tip a cow if its centre of mass were pushed over its hooves before the cow could react. However, cows are not rigid or unresponsive, and the faster humans have to move, the less force they can exert. Thus Lillie and Boechler concluded that it is unlikely that cows can actually be tipped over in this way. Lillie stated, "It just makes the physics of it all, in my opinion, impossible."

Although biologist Steven Vogel agrees that it would take a force of about 3,000 newtons to push over a standing cow, he thinks that the study by Lillie and Boechler overestimates the pushing ability of an individual human. Using data from Cotterell and Kamminga, who estimated that humans exert a pushing force of 280 newtons, Vogel suggests that someone applying force at the requisite height to topple a cow might generate a maximum push of no more than 300 newtons. By this calculation, at least 10 people would be needed to tip over a non-reacting cow. However, this combined force requirement, he says, might not be the greatest impediment to such a prank. Standing cows are not asleep and, like other animals, have ever-vigilant reflexes. "If the cow does no more than modestly widen its stance without an overall shift of its center of gravity", he says, "about 4,000 newtons or 14 pushers would be needed—quite a challenge to deploy without angering the cow."

Historical origins
The belief that certain animals cannot rise if pushed over has historical antecedents. Julius Caesar recorded a belief that a European elk had no knee joints and could not get up if it fell. Pliny said the same about the hind legs of an animal he called the achlis, which Pliny's 19th-century translators Bostock and Riley said was merely another name for the elk. They noted that Pliny's belief about the jointless back legs of the achlis (elk) was false.

In 1255, Louis IX of France gave an elephant to Henry III of England for his menagerie in the Tower of London. A drawing by the historian Matthew Paris for his Chronica Majora can be seen in his bestiary at Parker Library of Corpus Christi College, Cambridge. An accompanying text cites elephant lore suggesting that elephants did not have knees and were unable to get up if they fell.

Journalist Jake Steelhammer believes the American urban myth of cow tipping originated in the 1970s. It "stampeded into the '80s", he says, "when movies like Tommy Boy and Heathers featured cow tipping expeditions." Stories about cow tipping tend to be second-hand, he says, told by someone who does not claim to have tipped a cow but who knows someone else who says they did.

Veterinary and husbandry practices

Cattle may need to be deliberately thrown or tipped over for certain types of husbandry practices and medical treatment. When done for medical purposes, this is often called "casting", and when performed without mechanical assistance requires the attachment of 30 to 40 ft of rope around the body and legs of the animal. After the rope is secured by non-slip bowline knots, it is pulled to the rear until the animal is off-balance. Once the cow is forced to lie down in sternal recumbency (on its chest), it can be rolled onto its side and its legs tied to prevent kicking.

A calf table or calf cradle, also called a "tipping table" or a "throw down", is a relatively modern invention designed to be used on calves that are being branded. A calf is run into a chute, confined, and then tipped by the equipment onto its side for easier branding and castration.

Hydraulic tilt tables for adult cattle have existed since the 1970s and are designed to lift and tip cattle onto their sides to enable veterinary care, particularly of the animals' genitalia, and for hoof maintenance. (Unlike horses, cows generally do not cooperate with a farrier when standing.) A Canadian veterinarian explained, "Using the table is much safer and easier than trying to get underneath to examine the animal", and noted that cows tipped over on a padded table usually stop struggling and become calm fairly quickly. One design, developed at the Western College of Veterinary Medicine in Saskatoon, Saskatchewan, included "cow comfort" as a unique aspect of care using this type of apparatus.

Involuntary recumbency
Cows may inadvertently tip themselves. Due to their bulk and relatively short legs, cattle cannot roll over. Those that lie down and roll to their sides with their feet pointing uphill may become stuck and unable to rise without assistance, with potentially fatal results. In such cases, two humans can roll or flip a cow onto its other side, so that its feet are aimed downhill, thus allowing it to rise on its own. In one documented case of "real-life cow tipping", a pregnant cow rolled into a gully in New Hampshire and became trapped in an inverted state until rescued by volunteer fire fighters. The owner of the cow commented that he had seen this happen "once or twice" before.

Trauma or illness may also result in a cow unable to rise to its feet. Such animals are sometimes called "downers." Sometimes this occurs as a result of muscle and nerve damage from calving or a disease such as mastitis. Leg injuries, muscle tears, or a massive infection of some sort may also be causes. Downer cows are encouraged to get to their feet and have a much greater chance of recovery if they do. If unable to rise, some have survived—with medical care—as long as 14 days and were ultimately able to get back on their feet. Appropriate medical treatment for a downer cow to prevent further injury includes rolling from one side to the other every three hours, careful and frequent feeding of small amounts of fodder, and access to clean water.

Death
Dead animals may appear to have been tipped over, but this is actually the process of rigor mortis, which stiffens the muscles of the carcass, beginning six to eight hours after death and lasting for one to two days. It is particularly noticeable in the limbs, which stick out straight. Post-mortem bloat also occurs because of gas formation inside the body. The process may result in cattle carcasses that wind up on their back with all four feet in the air.

In popular culture

Assorted individuals have claimed to have performed cow tipping, often while under the influence of alcohol. These claims, to date, cannot be reliably verified, with Jake Swearingen of Modern Farmer noting in 2013 that YouTube, a popular source of videos of challenges and stunts, "fails to deliver one single actual cow-tipping video".

Pranksters have sometimes pushed over artificial cows. Along Chicago's Michigan Avenue in 1999, two "apparently drunk" men felled six fiberglass cows that were part of a Cows on Parade public art exhibit. Four other vandals removed a "Wow cow" sculpture from its lifeguard chair at Oak Street Beach and abandoned it in a pedestrian underpass. A year later, New York City anchored its CowParade art cows, including "A Streetcow Named Desire", to concrete bases "to prevent the udder disrespect of cow-tippers and thieves."

Cow tipping has been featured in films from the 1980s and later, such as Heathers (1988), Tommy Boy (1995),  Barnyard (2006), and I Love You, Beth Cooper (2009). It was also used in the title of a 1992 documentary film by Randy Redroad, Cow Tipping—The Militant Indian Waiter.

Variants of cow tipping have also been seen in popular media such as the film Cars (2006), which features a vehicular variant called tractor-tipping, and the video game Fallout: New Vegas, which allows the character to sneak up on and tip over a Brahmin, the game's two-headed cow-like animal. The board game Battle Cattle is based on the practice, with heavily armed cows having "Tipping Defense Numbers."

In The Little Willies song "Lou Reed" from their 2006 self-titled debut album, Norah Jones sings about a fictional event during which musician Lou Reed tips cows in Texas. In another medium, The Big Bang Theory, a television show, uses cow tipping lore as an element to establish the nature of a rural character, Penny.

The term cow tipping is sometimes used as a figure of speech for pushing over something big. In A Giant Cow-Tipping by Savages, author John Weir Close uses the term to describe contemporary mergers and acquisitions. "Tipping sacred cows" has been used as a deliberate mixed metaphor in titles of books on Christian ministry and business management.

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Cassandra

Cassandra or Kassandra (Ancient Greek: Κασσάνδρα,, also Κασσάνδρα, and sometimes referred to as Alexandra) in Greek mythology was a Trojan priestess dedicated to the god Apollo and fated by him to utter true prophecies but never to be believed. In modern usage her name is employed as a rhetorical device to indicate a person whose accurate prophecies, generally of impending disaster, are not believed.

Cassandra was a daughter of King Priam and Queen Hecuba of Troy. Her elder brother was Hector, the hero of the Greek-Trojan War. The older and most common versions of the myth state that she was admired by the god Apollo, who sought to win her love by means of the gift of seeing the future. According to Aeschylus, she promised him her favours, but after receiving the gift, she went back on her word. As the enraged Apollo could not revoke a divine power, he added to it the curse that nobody would believe her prophecies. In other sources, such as Hyginus and Pseudo-Apollodorus, Cassandra broke no promise to Apollo, but rather the power of foresight was given to her as an enticement to enter into a romantic engagement, the curse being added only when it failed to produce the result desired by the god.

Later versions on the contrary describe her falling asleep in a temple, where snakes licked (or whispered into) her ears which enabled her to hear the future.

Etymology
Hjalmar Frisk (Griechisches Etymologisches Wörterbuch, Heidelberg, 1960–1970) notes "unexplained etymology", citing "various hypotheses" found in Wilhelm Schulze, Edgar Howard Sturtevant, J. Davreux, and Albert Carnoy. R. S. P. Beekes cites García Ramón's derivation of the name from the Proto-Indo-European root *(s)kend- "raise". The Online Etymology Dictionary states "though the second element looks like a fem. form of Greek andros "of man, male human being." Watkins suggests PIE *(s)kand- "to shine" as source of second element. The name also has been connected to kekasmai "to surpass, excel. "

Description
Cassandra was described by the chronicler Malalas in his account of the Chronography as "shortish, round-faced, white, mannish figure, good nose, good eyes, dark pupils, blondish, curly, good neck, bulky breasts, small feet, calm, noble, priestly, an accurate prophet foreseeing everything, practicing hard, virgin". Meanwhile, in the account of Dares the Phrygian, she was illustrated as ". . .of moderate stature, round-mouthed, and auburn-haired. Her eyes flashed. She knew the future."

Biography

Cassandra was one of the many children born to the king and queen of Troy, Priam and Hecuba. She is the fraternal twin sister of Helenus, as well as the sister to Hector and Paris. One of the oldest and most common versions of her myth states that Cassandra was admired for her beauty and intelligence by the god Apollo, who sought to win her with the gift to see the future. According to Aeschylus, Cassandra promised Apollo favors, but, after receiving the gift, went back on her word and refused Apollo. Since the enraged Apollo could not revoke a divine power, he added a curse that nobody would believe Cassandra's prophecies.

Mythology
Cassandra appears in texts written by Homer, Virgil, Aeschylus and Euripides. Each author depicts her prophetic powers differently.

In Homer's work, Cassandra is mentioned a total of four times "as a virgin daughter of Priam, as bewailing Hector's death, as chosen by Agamemnon as his slave mistress after the sack of Troy, and is killed by Clytemnestra over Agamemnon's corpse after Clytemnestra murders him on his return home. "

In Virgil's work, Cassandra appears in book two of his epic poem titled Aeneid, with her powers of prophecy restored. In Book 2 of the Aeneid, unlike Homer, Virgil presents Cassandra as having fallen into a mantic state and her prophecies reflect it. Likewise Seneca the Younger, in his play Agamemnon, has her prophesy why Agamemnon deserves the death he got: ''Quid me vocatis sospitem solam e meis, umbrae meorum? te sequor, tota pater Troia sepulte; frater, auxilium Phrygum terrorque Danaum, non ego antiquum decus video aut calentes ratibus ambustis manus, sed lacera membra et saucios vinclo gravi illos lacertos. te sequor… (Ag. 741–747)''

''Why do you call me, the lone survivor of my family, My shades? I follow you, father buried with all of Troy; Brother, bulwark of Trojans, terrorizer of Greeks, I do not see your beauty of old or hands warmed by burnt ships, But your lacerated limbs and those famous shoulders savaged By heavy chains. I follow you... Later on in Seneca's work, this behavior is reflected in acts 4 and 5 as "Her mantic vision in act 4 will be supplemented by a further (in)sight into what is going on inside the palace in act 5 when she becomes a quasi-messenger and provides a meticulous account of Agamemnon's murder in the bath: 'I see and I am there and I enjoy it, no false vision deceives my eyes: let's watch' (video et intersum et fruor, / imago visus dubia non fallit meos: / spectemus''.) "

Gift of prophecy
Cassandra was given the gift of prophecy, but was also cursed by the god Apollo so that her true prophecies would not be believed. Many versions of the myth relate that she incurred the god's wrath by refusing him sexual favours after promising herself to him in exchange for the power of prophecy. In Aeschylus' Agamemnon, she bemoans her relationship with Apollo: Apollo, Apollo! God of all ways, but only Death's to me, Once and again, O thou, Destroyer named, Thou hast destroyed me, thou, my love of old!

And she acknowledges her fault: "I consented [marriage] to Loxias [Apollo] but broke my word. ... Ever since that fault I could persuade no one of anything."

Latin author Hyginus in Fabulae says:

Louise Bogan, an American poet, writes that another way Cassandra, as well as her twin brother Helenus, had earned their prophetic powers: "she and her brother Helenus were left overnight in the temple of the Thymbraean Apollo. No reason has been advanced for this night in the temple; perhaps it was a ritual routinely performed by everyone. When their parents looked in on them the next morning, the children were entwined with serpents, which flicked their tongues into the children's ears. This enabled Cassandra and Helenus to divine the future." It would not be until Cassandra is much older that Apollo appears in the same temple and tried to seduce Cassandra, who rejects his advances, and curses her by making her prophecies not be believed.

Her cursed gift from Apollo became an endless pain and frustration to her. She was seen as a liar and a madwoman by her family and by the Trojan people. Because of this, her father, Priam, had locked her away in a chamber and guarded her like the madwoman she was believed to be. Though Cassandra made many predictions that went unbelieved, the one prophecy that was believed was that of Paris being her abandoned brother.

Before the fall of Troy
Before the fall of Troy took place, Cassandra foresaw that if Paris went to Sparta and brought Helen back as his wife, the arrival of Helen would spark the downfall and destruction of Troy during the Trojan War. Despite the prophecy and ignoring Cassandra's warning, Paris still went to Sparta and returned with Helen. While the people of Troy rejoiced, Cassandra, angry with Helen's arrival, furiously snatched away Helen's golden veil and tore at her hair.

In Virgil's epic poem, the Aeneid, Cassandra warned the Trojans about the Greeks hiding inside the Trojan Horse, Agamemnon's death, her own demise at the hands of Aegisthus and Clytemnestra, her mother Hecuba's fate, Odysseus's ten-year wanderings before returning to his home, and the murder of Aegisthus and Clytemnestra by the latter's children Electra and Orestes. Cassandra predicted that her cousin Aeneas would escape during the fall of Troy and found a new nation in Rome.

During the fall of Troy
Coroebus and Othronus came to the aid of Troy during the Trojan War out of love for Cassandra and in exchange for her hand in marriage, but both were killed. According to one account, Priam offered Cassandra to Telephus's son Eurypylus, in order to induce Eurypylus to fight on the side of the Trojans. Cassandra was also the first to see the body of her brother Hector being brought back to the city.In The Fall of Troy, told by Quintus Smyrnaeus, Cassandra attempted to warn the Trojan people that Greek warriors were hiding in the Trojan Horse while they were celebrating their victory over the Greeks with feasting. Disbelieving Cassandra, the Trojans resorted to calling her names and hurling insults at her. Attempting to prove herself right, Cassandra took an axe in one hand and a burning torch in the other, and ran towards the Trojan Horse, intent on destroying the Greeks herself, but the Trojans stopped her. The Greeks hiding inside the Horse were relieved, but alarmed by how clearly she had divined their plan. At the fall of Troy, Cassandra sought shelter in the temple of Athena. There she embraced the wooden statue of Athena in supplication for her protection, but was abducted and brutally raped by Ajax the Lesser. Cassandra clung so tightly to the statue of the goddess that Ajax knocked it from its stand as he dragged her away. The actions of Ajax were a sacrilege because Cassandra was a supplicant at the sanctuary, and under the protection of the goddess Athena and Ajax further defiled the temple by raping Cassandra.

In Apollodorus chapter 6, section 6, Ajax's death comes at the hands of both Athena and Poseidon: "Athena threw a thunderbolt at the ship of Ajax; and when the ship went to pieces he made his way safe to a rock, and declared that he was saved in spite of the intention of Athena. But Poseidon smote the rock with his trident and split it, and Ajax fell into the sea and perished; and his body, being washed up, was buried by Thetis in Myconos".

In some versions, Cassandra intentionally left a chest behind in Troy, with a curse on whichever Greek opened it first. Inside the chest was an image of Dionysus, made by Hephaestus and presented to the Trojans by Zeus. It was given to the Greek leader Eurypylus as a part of his share of the victory spoils of Troy. When he opened the chest and saw the image of the god, he went mad.

The aftermath of Troy and Cassandra's death
Once Troy had fallen, Cassandra was taken as a pallake (concubine) by King Agamemnon of Mycenae. While he was away at war, Agamemnon's wife, Clytemnestra, had taken Aegisthus as her lover. Cassandra and Agamemnon were later killed by either Clytemnestra or Aegisthus. Various sources state that Cassandra and Agamemnon had twin boys, Teledamus and Pelops, who were murdered by Aegisthus.

The final resting place of Cassandra is either in Amyclae or Mycenae. Statues of Cassandra exist both in Amyclae and across the Peloponnese peninsula from Mycenae to Leuctra. In Mycenae, German business man and pioneer archeologist Heinrich Schliemann discovered in Grave Circle A the graves of Cassandra and Agamemnon and telegraphed back to King George I of Greece:"With great joy I announce to Your Majesty that I have discovered the tombs which the tradition proclaimed by Pausanias indicates to be the graves of Agamemnon, Cassandra, Eurymedon and their companions, all slain at a banquet by Clytemnestra and her lover Aegisthos."However, it was later discovered that the graves predated the Trojan War by at least 300 years.

Agamemnon by Aeschylus

The play Agamemnon from Aeschylus's trilogy Oresteia depicts the king treading the scarlet cloth laid down for him, and walking offstage to his death. After the chorus's ode of foreboding, time is suspended in Cassandra's "mad scene". She has been onstage, silent and ignored. Her madness that is unleashed now is not the physical torment of other characters in Greek tragedy, such as in Euripides' Heracles or Sophocles' Ajax.

According to author Seth Schein, two further familiar descriptions of her madness are that of Heracles in The Women of Trachis or Io in Prometheus Bound. He specifies that her madness is not the type that uses language to descriptive physical agony or other physical symptoms. Instead, she speaks, disconnectedly and transcendent, in the grip of her psychic possession by Apollo, witnessing past and future events. Schein says, "She evokes the same awe, horror and pity as do schizophrenics". Cassandra is one of those "who often combine deep, true insight with utter helplessness, and who retreat into madness."

Eduard Fraenkel remarked on the powerful contrasts between declaimed and sung dialogue in this scene. The frightened and respectful chorus are unable to comprehend her. She goes to her inevitable offstage murder by Clytemnestra with full knowledge of what is to befall her.

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Talk:Cassandra

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Correct spelling of Kassandra to the closest approximation of the original Greek spelling
Cassandra is a mythological figure from Greek history. I suggest that spelling the name with an initial "K" to match the Greek letter Kappa would be more correct than beginning with the name with a "C" which does not exist in the Greek alphabet. — Preceding unsigned comment added by Lakazdi (talk • contribs) 14:30, 19 May 2017 (UTC)

Untitled
A tragic figure, yes, but some context would be nice ! --Anders Törlind

 * well really Apollo liked Cassandra, apollo asked cassandr to kiss him and she would get the gift of seeing the future and that went down hill from there —Preceding semi-signed comment added by "~*NiCoLe*~" 24.239.97.232 (talk) 21:07, 14 April 2008

Modern usage
Most of the items here reference people who appear to only be mentioned in this entry. Do I sense self-promotion? —Preceding unsigned comment added by 209.6.170.137 (talk) 23:33, 14 October 2007 (UTC)

 * Here's a usage that is well-confirmed: Cassandra, the database management system. Perhaps an explanation of why the folks chose the name, if interesting. 09:19, 21 January 2012 (UTC) — Preceding unsigned comment added by 68.194.119.45 (talk)

 * This is yet another section in a mythology article that threatens to turn the article into just a big long list of characters and episode synopses from TV shows. This is getting old. Andy Christ (talk) 06:29, 13 January 2008 (UTC)

well not everything here is true but alot of it is right and all of this is very interesting well that i thought but weird at the same time well really Apollo liked Cassandra, apollo asked cassandr to kiss him and she would get the gift of seeing the future and that went down hill from there ~*NiCoLe*~  —Preceding unsigned comment added by 24.239.97.232 (talk) 21:08, 14 April 2008 (UTC)

 * Seems that "Modern Usage" is the new name for the now discredited trivia section - ie a dumping ground for a mass of irrelevant cruft. Millions of people have said things which were not believed but turned out to be true. That doesn't mean they are relevant to this article. And yes, there is an awful lot of promotion of nonentities here. 79.76.228.75 (talk) 12:20, 17 April 2009 (UTC)

 * Ug, modern usage. If we listed every time such a famous character was referenced or alluded to, we'd have several hundred thousand words of such descriptions.  It should just say 'Cassandra's name is frequently invoked in relation to prophecy, especially prophecy that isn't believed, in modern fiction' and trim most of this cruft.  Maybe I'll go and just do that. --2602:30A:2EA0:D9F0:EC0D:DDBF:D12C:5D69 (talk) 21:12, 13 June 2014 (UTC)

"Occasionally people with various psychic (or "psi") abilities use this term" This presumes the existence of people with psychic abilities, which is a moot point. Should it be rephrased to be impartial on this issue, or linked to the article on clairvoyance? —Preceding unsigned comment added by 80.177.6.97 (talk) 23:13, 13 April 2009 (UTC)

could someone add the red dwarf episode where there is a computer ai who has the physical form of a female human with the name cassandra. she also can tell the future and foresees her death at the hand of lister, who tries to avoid fulfilling this prophecy. of course he still kills destroys/cassandra through a rube goldberg like series of events. —Preceding unsigned comment added by 220.101.92.126 (talk) 08:50, 26 January 2010 (UTC)

more examples of use in other fields
i added another use i just stumbled on in an article by renowned historian Dr.Patrick Finney. mpearse 11:50, 25 September 2006 (UTC)

Nonsequitur
The article states that "Upon Agamemnon and Cassandra's arrival in Mycenae, Clytemnestra asked her husband to walk across a purple carpet; he initially refused then gave in and entered, not believing Cassandra's warnings." Although it previously mentioned that she predicted Ag's death, it was simply a cursory mention devoid of detail. It never previously mentioned anything about a purple carpet being involved. This therfore comes off as a nonsequitur. I am pointing this out for correction rather than correcting it myself because I don't know if she warned him not to walk on a purple carpet, to avoid purple, to not do what his wife asked, to avoid carpets in Mycenae, or any number of other possibilities. Someone please fix this. -68.196.0.191 13:52, 23 September 2005 (UTC)

 * Weren't all of Cassandra's warnings ones of doom and destruction? In that sense, the use in the Grauniad would be correct, though shallow. — Preceding unsigned comment added by 159.153.176.45 (talk) 14:19, 25 January 2006

"Symmetrical contrast"
I deleted "Thus, a man whose prophecies are believed but do not come about stands in symmetrical contrast to a woman whose prophecies are disbelieved but come true", as it has a clear sexist (in this case, anti-male) subcontext, whether intentional or not. Furthermore, this "symmetry" can not exist between such distinct, independent traditions as ancient greek and judean mythology, as they are not comparable traditions. It is also a POV, which adds nothing informative to the subject. — Preceding unsigned comment added by 213.240.3.226 (talk) 06:16, 5 February 2006

 * Israel and Greece are both in the Eastern Mediterranean, which is far from being an impenetrable ocean. The Greek alphabet is derived from the Phoenician alphabet. There is no reason why the traditions could not have cross-fertilized. But even if Greece and Israel were thousands of miles apart or on different planets, it is most interesting that Jonah and Cassandra are in such structurally symmetric positions. Both of them, moreover, ended up very unhappy - Jonah as distressed by the non-fulfillment of his prophecy of doom as Cassandra was by the fulfillment of hers. You make a very good point, Anonymous, by bringing up the matter of gender. Perhaps if Cassandra had been a man she would have been believed. Perhaps if Jonah had been a woman he would not have been believed. Then Troy would have survived, but Niniveh would not. Das Baz 15:47, 23 June 2006 (UTC)

 * Oh yes, and it is an egregious absurdity to say that any contrast of public reactions to male and female pronouncements, implicit or explicit, intentional or not, is "sexist." Suppose someone said that a Black Prophet (like Dr. Martin Luther King Jr.) was disbelieved while a White Prophet was believed - would this be "racist"?Das Baz 15:52, 23 June 2006 (UTC)

A Tale of Two Cities
Troy and Niniveh are both in the Near Eastern cultural area, and only a few hundred miles apart from each other. Many people travelled between the two cities, as they were both major centers of trade and commerce. Das Baz 16:29, 24 June 2006 (UTC)

Curse
I really think that the caveat of the gods that she would not believed should be mentioned in the opening. That's perhaps the single most important thing about the Cassandra myth. --DanielCD 02:58, 9 February 2006 (UTC)

Reality of Cassandra
"Much of Homer's story of Troy was real as proven by Heinrich Schliemann that discovered the city. We know that there was a Troy that was destroyed in war, right in the place that Homer said. There was also a King that likely had daughters. The earliest known version of the story did not say Cassandra had the power to tell the future. Beyond that, little is known for sure."

This is a highly dubious claim to make. A city most likely Ilium was discovered along the coast of Turkey by Schliemann, yes. However, to say that "much of Homer's story" was proven by Schliemann is a very shoddy assertion (even while excluding his notoriously destructive and careless excavation techniques). How is the real Troy similar to Homer's descriptions? How do you know there was a king? Was there only one king the entire time? When did he rule? —The preceding unsigned comment was added by 70.178.216.95 (talk • contribs).

 * I removed that section, as it isn't referenced anyway, and I agree it serves little purpose and gives no reliable information. --DanielCD 14:14, 8 April 2006 (UTC)

In the Movies
The Cassandra Crossing - The Cassandra Crossing — Preceding unsigned comment added by Crosbie Fitch (talk) 14:08, 15 August 2006

 * Yes, shouldn't there be some reference to this film in the article? I'm sure the naming of the bridge in the film is a reference to the fact that they know they are going to their doom, but they are powerless to stop it. VenomousConcept (talk) 15:00, 4 October 2011 (UTC)

 * WP:OR -- SmashTheState (talk) 20:03, 4 October 2011 (UTC)

Suggestions
Recommend the first reference to Agamemnon become a hyperlink to relevant article.

I haven't edited Wikipedia myself, but I'd like to suggest in this article, a reference be made to the Zathras character in the Sci-Fi TV series Babylon 5. Zathras is definitely the Cassandra of B5, predicting things no one understands or believes. "Zathras warn, but no one listens to poor Zathras. That is OK, Zathras is used to it." Zathras has his own wiki article. -Lepton68 —Preceding unsigned comment added by Lepton68 (talk • contribs) 17:31, 22 October 2008 (UTC)

 * Cassandra as the prototype of unheeded seers is noted: a list of unheeded seers could become excruciatingly jejune.--Wetman (talk) 18:36, 22 October 2008 (UTC)

Adam? Eric? Dean?
Has somebody been playing with this page? Peter Delmonte 01:15, 29 March 2007 (UTC)

 * Yes, and I've reverted it. --Bruce1ee 05:29, 29 March 2007 (UTC)

No Man's Land
Cassandra is also noticed in an acclaimed novel that was originally a comic book written by Greg Rucka: Batman: No Man's Land. In the book she is known as "the future" of weapons.

Um...what is this? Is there an actual weapon named Cassandra? As far as I know, the only Cassandra is that of Cassandra Cain, who hsa the gift of being able to read body language at the cost of her speaking ability. In any case...it's one of probably hundreds of thousands of references to Cassandra. It doesn't belong in this article. hbdragon88 (talk) 00:55, 24 October 2009 (UTC)

Something wrong with a template
The Greek name appears like this on the page: Κασσάνδρα{{Cat handler |main= (talk) 19:18, 3 June 2010 (UTC)

Graves
The article gives "she who entangles men" as an etymology presented by Robert Graves. Now even if this was referenced (it isn't, presumably The Greek Myths?) it would be worthless, as Graves' essentially used the Greek myths as a quarry to construct his own myth of a Triple Goddess, he didn't study them on their own terms. --dab (𒁳) 15:09, 7 November 2010 (UTC)

Lack of sources
1. "In an alternative version, she spent a night at Apollo's temple"

Who wrote this version?

2. "In some versions of the myth, this is symbolized by the god spitting into her mouth; in other Greek versions, this act was sufficient to remove the gift so recently given by Apollo, but Cassandra's case varies."

What are the sources of these?

3. "Some sources mention that Cassandra and Agamemnon had twin boys, Teledamus and Pelops, both of whom were killed by Aegisthus."

What sources are these?

ICE77 (talk) 05:24, 1 June 2011 (UTC)

Julianbce edits
Your edits don't seem to make logical sense. There are serious grammatical problems which make them unintelligible. They are also unreferenced, and appear to by original research. They also appear to be fancruft in the sense that they are about Disney, not about Cassandra. The material is not in itself notable. You have also reverted 5 times in a short period in an attempt to force your material into the article. This should be discussed here before there is any further edit warring. SmashTheState (talk) 07:23, 18 June 2011 (UTC)

Modern adaptations tagging
I've tagged quite a number of the "Modern Adaptations" with citation needed templates. Unless reliable sources are presented which verify that these are based on the Cassandra myth, they must be removed. We cannot ourselves interpret which "retellings" are related to Cassandra and which are not; doing so would be original research. Qwyrxian (talk) 03:32, 22 February 2012 (UTC)

 * I think the connection of new stories to old stories is of interest. Tagging of original research is appropriate and desirable, but I don't think removal is the right action if the modern adaptation has very similar themes or character/place names that it must have been inspired by the original. Having said that, I think the statement "The motion picture Contact based upon Carl Sagan's novel borrows the myth with Jodie Foster playing the Cassandra figure and Matthew McConaughey as the Apollo figure" should be removed promptly, unless a reliable source is presented, because the well known movie Contact has zero similarity to the Cassandra myth. I cannot comment on the others because I am not familiar with them. — Preceding unsigned comment added by 70.171.247.181 (talk) 00:33, 28 November 2012

Wolfe
I read the Christa Wolf story about ten years ago. I don't remember it being told at the moment of Cassandra'a death.

Is there a source for this: "a beautiful girl with red hair kept in curls, blue eyes, and fair skin"? — Preceding unsigned comment added by Howunusual (talk • contribs) 21:18, 11 December 2013 (UTC)

Who was the most beautiful woman in the world?
The history section has: "... she was depicted to be the second most beautiful woman in the world with her beauty even compared to that of Aphrodite and Helen of Troy." So, who was the most beautiful? Helen? If so, the sentence could be better worded: "... she was depicted to be second in beauty only to Helen of Troy, and even compared to the goddess Aphrodite."--ML5 (talk) 13:19, 14 February 2014 (UTC)

Overhauling the article
Cassandra was one of my favorite subjects back in ye olde college days, and I'd like to improve this article. After watching the article for some time, I think a source-by-source approach might be best.

Any thoughts on the best way to structure this? What approaches have been used with multi-source, multi-story mythological figures before? Howunusual (talk) 22:22, 14 April 2014 (UTC)

Cassandra was an idiot they say but she was cursed by apllo The curs was that know one would ever belive her. But wen she fel asleep in a tempel snakes wispered in her eras And that was alowing her To hear the future — Preceding unsigned comment added by 81.62.239.127 (talk) 14:25, 4 June 2014 (UTC)

Additional items needing source
This from the article is very interesting:

Snakes as a source of knowledge is a recurring theme in Greek mythology, although sometimes the snake brings understanding of the language of animals rather than an ability to know the future.

The article would benefit from a source or sources for the several statements there. I think many readers would be interested in pursuing the ideas further by secondary sources outside Wikipedia.

Ken M Quirici 16:27, 11 June 2015 (UTC) — Preceding unsigned comment added by Kquirici (talk • contribs)

Mythical!
She is a mythical character of a mythical king! Should be clear about this in the first sentence — Preceding unsigned comment added by 208.89.33.72 (talk) 00:26, 17 November 2016 (UTC)

Cassandra was so beautiful she had to sleep in the temple(so no one could kidnap her) made for Apollo. The god went to his temple and saw a beautiful woman. He instantly fell in love with her, he gave her a gift to see the future when she was asleep. When Cassandra woke up he proposed to her but as she saw Apollo destroying troy in the future she said “No!” Apollo was unhappy so gave her another gift of disbelief so no one would believe her. — Preceding unsigned comment added by 92.237.75.129 (talk) 18:40, 2 February 2018 (UTC)

A Commons file used on this page has been nominated for deletion
The following Wikimedia Commons file used on this page has been nominated for deletion: Participate in the deletion discussion at the. —Community Tech bot (talk) 16:36, 15 January 2020 (UTC)
 * "Crater with red figures" (350-340 BC) "Cassandra and Ajax" .jpg

prediction of Rome
the articles says that she predicted the foundation of Rome by Aeneas but doesn't say that it's a later Roman invention. Yes it sources to Virgil but still shouldn't that detail be stated explicitly? No other prediction goes outside the time when Iliad and Odyssey were composed but this does.

Wiki Education assignment: Rethinking Revenge
— Assignment last updated by Polykarpiris (talk) 18:50, 31 May 2024 (UTC)

title: Talk:Cassandra


text:
Couplet

In poetry, a couplet or distich is a pair of successive lines that rhyme and have the same metre. A couplet may be formal (closed) or run-on (open). In a formal (closed) couplet, each of the two lines is end-stopped, implying that there is a grammatical pause at the end of a line of verse. In a run-on (open) couplet, the meaning of the first line continues to the second.

Background
The word "couplet" comes from the French word meaning "two pieces of iron riveted or hinged together". The term "couplet" was first used to describe successive lines of verse in Sir P. Sidney's Arcadia in 1590: "In singing some short coplets, whereto the one halfe beginning, the other halfe should answere."

While couplets traditionally rhyme, not all do. Poems may use white space to mark out couplets if they do not rhyme. Couplets in iambic pentameter are called heroic couplets. John Dryden in the 17th century and Alexander Pope in the 18th century were both well known for their writing in heroic couplets. The Poetic epigram is also in the couplet form. Couplets can also appear as part of more complex rhyme schemes, such as sonnets.

Rhyming couplets are one of the simplest rhyme schemes in poetry. Because the rhyme comes so quickly, it tends to call attention to itself. Good rhyming couplets tend to "explode" as both the rhyme and the idea come to a quick close in two lines. Here are some examples of rhyming couplets where the sense as well as the sound "rhymes":

 * True wit is nature to advantage dress'd;
 * What oft was thought, but ne'er so well express'd.
 * — Alexander Pope

 * Whether or not we find what we are seeking
 * Is idle, biologically speaking.
 * — Edna St. Vincent Millay (at the end of a sonnet)

On the other hand, because rhyming couplets have such a predictable rhyme scheme, they can feel artificial and plodding. Here is a Pope parody of the predictable rhymes of his era:
 * Where-e'er you find "the cooling western breeze,"
 * In the next line, it "whispers through the trees;"
 * If crystal streams "with pleasing murmurs creep,"
 * The reader's threatened (not in vain) with "sleep."

In English poetry
Regular rhyme was not originally a feature of English poetry: Old English verse came in metrically paired units somewhat analogous to couplets, but constructed according to alliterative verse principles. The rhyming couplet entered English verse in the early Middle English period through the imitation of medieval Latin and Old French models. The earliest surviving examples are a metrical paraphrase of the Lord's Prayer in short-line couplets, and the Poema Morale in septenary (or "heptameter") couplets, both dating from the twelfth century.

Rhyming couplets were often used in Middle English and early modern English poetry. Chaucer's Canterbury Tales, for instance, is predominantly written in rhyming couplets, and Chaucer also incorporated a concluding couplet into his rhyme royal stanza. Similarly, Shakespearean sonnets often employ rhyming couplets at the end to emphasize the theme. Take one of Shakespeare's most famous sonnets, Sonnet 18, for example (the rhyming couplet is shown in italics):

 * Shall I compare thee to a summer's day?
 * Thou art more lovely and more temperate:
 * Rough winds do shake the darling buds of May,
 * And summer's lease hath all too short a date:
 * Sometimes too hot the eye of heaven shines,
 * And often is his gold complexion dimm'd;
 * And every fair from fair sometime declines,
 * By chance or nature's changing course untrimm'd;
 * But thy eternal summer shall not fade
 * Nor lose possession of that fair thou owest;
 * Nor shall Death brag thou wander'st in his shade,
 * When in eternal lines to time thou growest:
 * So long as men can breathe or eyes can see,
 * So long lives this and this gives life to thee.

In the late seventeenth century and early eighteenth-century English rhyming couplets achieved the zenith of their prestige in English verse, in the popularity of heroic couplets. The heroic couplet was used by famous poets for ambitious translations of revered Classical texts, for instance, in John Dryden's translation of the Aeneid and in Alexander Pope's translation of the Iliad.

Though poets still sometimes write in couplets, the form fell somewhat from favour in English in the twentieth century; contemporary poets writing in English sometimes prefer unrhymed couplets, distinguished by layout rather than by matching sounds.

In Chinese poetry
Couplets called duilian may be seen on doorways in Chinese communities worldwide. Duilian displayed as part of the Chinese New Year festival, on the first morning of the New Year, are called chunlian (春联). These are usually purchased at a market a few days before and glued to the doorframe. The text of the couplets is often traditional and contains hopes for prosperity. Other chunlian reflect more recent concerns. For example, the CCTV New Year's Gala usually promotes couplets reflecting current political themes in mainland China.

Some duilian may consist of two lines of four characters each. Duilian are read from top to bottom where the first line starts from the right.

In Tamil poetry
Tamil literature contains some of the notable examples of ancient couplet poetry. The Tamil language has a rich and refined grammar for couplet poetry, and distichs in Tamil poetry follow the venpa metre. One of the most notable examples of Tamil couplet poetry is the ancient Tamil moral text of the Tirukkural, which contains a total of 1330 couplets written in the kural venpa metre from which the title of the work was derived centuries later. Each Kural couplet is made of exactly 7 words—4 in the first line and 3 in the second. The first word may rhyme with the fourth or the fifth word. Below is an example of a couplet:

 * இலன்என்று தீயவை செய்யற்க செய்யின்
 * இலனாகும் மற்றும் பெயர்த்து. (Tirukkural, verse 205)

 * Transliteration: Ilan endru theeyavai seyyarkka seyyin
 * Ilanaagum matrum peyartthu

 * Translation: Make not thy poverty a plea for ill;
 * Thine evil deeds will make thee poorer still. (Pope, 1886)

In Hindi poetry
In Hindi, a couplet is called a doha, while in Urdu, it is called a sher.

Couplets were the most common form of poetry between the 12th and 18th Centuries, in Hidustani. Famous poets include Kabir, Tulsidas and Rahim Khan-i-Khanan.

Kabir (also known as Kabirdas) is thought to be one of the greatest composers of Hindustani couplets.

Distich
The American poet J. V. Cunningham was noted for many distichs included in the various forms of epigrams included in his poetry collections, as exampled here:

Deep summer, and time passes. Sorrow wastes To a new sorrow. While Time heals time hastes

title: Couplet