Cosmological argument

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).[18] In other words, even if the Universe has always existed, it still owes its existence to an uncaused cause,[19] Aquinas further said: "... and this we understand to be God."[20]

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[21]

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."[22]

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.[23]

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.[24] 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).[25][26]

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.[27]

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.[28]

William Lane Craig, who was principally responsible for re-popularizing this argument in Western philosophy, presents it in the following general form:[29]

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.[30]

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:[31]

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."

One objection to the argument asks why 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.[36] Critics often press that arguing for the first cause's exemption raises the question of why the first cause is indeed exempt,[41] 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.[42] Defenders also note that the properties of the first cause such as lack of actualized potentials, lack of parts which need to be composed, lack of change, eternality, are precisely the features of that which requires no more fundamental cause, and that other mundane objects require causes for precisely those reasons such as the aforementioned.

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.[43] 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.[44] He argues Occam's razor may be employed to remove unneeded further causes of the universe to leave a single uncaused cause.[45]

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.[46] Opponents of the argument tend to argue that it is unwise to draw conclusions from an extrapolation of causality beyond experience.[1] 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,[47] therefore there must be an uncaused first cause that is beginningless and does not require a cause.[48]

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.[49] 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.[1]

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.[50] 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.

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."[51] 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.[52]

David Hume and later Paul Edwards have invoked a similar principle in their criticisms of the cosmological argument.[53] 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.[53]

Nevertheless, David White argues that the notion of an infinite causal regress providing a proper explanation is fallacious.[54] 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.[55][56] 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.[57] 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.[58] White tried to introduce an argument "without appeal to the principle of sufficient reason and without denying the possibility of an infinite causal regress".[59] 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.[60]

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.[61] 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.

Some cosmologists and physicists argue that a challenge to the cosmological argument is the nature of time: "One finds that time just disappears from the Wheeler–DeWitt equation"[62] (Carlo Rovelli). The Big Bang theory states that it is the point in which all dimensions came into existence, the start of both space and time.[63] Then, the question "What was there before the Universe?" makes no sense; the concept of "before" becomes meaningless when considering a situation without time.[63] 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.[63] However, some cosmologists and physicists do attempt to investigate causes for the Big Bang, using such scenarios as the collision of membranes.[64]

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.[65]