The Kalam cosmological argument is a modern formulation of the cosmological argument for the existence of God. It is named after the Kalam (medieval Islamic scholasticism), from which its key ideas originated. William Lane Craig was principally responsible for giving new life to the argument in the 20th century, due to his book The Kalām Cosmological Argument (1979), among other writings.
The argument's key underpinning idea is the metaphysical impossibility of actual infinities and of a temporally past-infinite universe, traced by Craig to 11th-century Persian Muslim scholastic philosopher Al-Ghazali. This feature distinguishes it from other cosmological arguments, such as that of Thomas Aquinas, which rests on the impossibility of a causally ordered infinite regress, and those of Leibniz and Samuel Clarke, which refer to the principle of sufficient reason.[1]
Since Craig's original publication, the Kalam cosmological argument has elicited public debate between Craig and Graham Oppy, Adolf Grünbaum, J. L. Mackie and Quentin Smith, and has been used in Christian apologetics.[2] According to Michael Martin, the cosmological arguments presented by Craig, Bruce Reichenbach, and Richard Swinburne are "among the most sophisticated and well argued in contemporary theological philosophy".[3]
The most prominent form of the argument, as defended by William Lane Craig, states the Kalam cosmological argument as the following syllogism:[4]
Given the conclusion, Craig appends a further premise and conclusion based upon a philosophical analysis of the properties of the cause of the universe:[5]
Referring to the implications of Classical Theism that follow from this argument, Craig writes:[6]
The Kalam cosmological argument was influenced by the concept of the prime-mover, introduced by Aristotle. The argument comes from the works of the theologian and philosopher John Philoponus (490–570 AD),[7] who has been called its "father".[8] The argument was substantially developed in medieval Islamic tradition during the Islamic Golden Age; for this reason, the name of the argument has been prefixed with the term kalām to recognize the contributions made during this period.[9] Important historical proponents include Al-Kindi,[10] Al-Ghazali,[11] and St. Bonaventure.[12][13][14]
One of the earliest formulations of the Kalam cosmological argument in the Islamic philosophical tradition comes from Al-Ghazali, who writes:
Between the 9th to 12th centuries, the cosmological argument developed as a concept within Islamic theology. It was refined in the 11th century by Al-Ghazali (The Incoherence of the Philosophers), and in the 12th by Ibn Rushd (Averroes).[16] It reached medieval Christian philosophy in the 13th century and was discussed by Bonaventure, as well as Thomas Aquinas in his Summa Theologica (I, q.2, a.3) and Summa Contra Gentiles (I, 13).
Islamic perspectives may be divided into positive Aristotelian responses strongly supporting the argument, such as those by Al-Kindi, and Averroes, and negative responses critical of it, including those by Al-Ghazali and Muhammad Iqbal.[17] Al-Ghazali was unconvinced by the first-cause arguments of Al-Kindi, arguing that only the infinite per se (that is an essentially ordered infinite series) is impossible, arguing for the possibility of the infinite per accidens (that is an accidentally ordered infinite series). He writes:
Muhammad Iqbal also stated:
"To finish the series at a certain point, and to elevate one member of the series to the dignity of an uncaused first cause, is to set at naught the very law of causation on which the whole argument proceeds."[19]
According to the atheist philosopher Quentin Smith, "a count of the articles in the philosophy journals shows that more articles have been published about Craig's defense of the Kalam argument than have been published about any other philosopher's contemporary formulation of an argument for God's existence."[20]
The Kalam cosmological argument has received criticism from philosophers such as J. L. Mackie, Graham Oppy, Michael Martin, Quentin Smith, Wes Morriston, Alex Malpass, and Daniel Linford, physicists Paul Davies, Lawrence Krauss and Victor Stenger, and authors such as Dan Barker.[21]
Modern discourse encompasses the fields of both philosophy and science (e.g. the fields of quantum physics and cosmology), which Bruce Reichenbach summarises as:
Since the temporal ordering of events is central, the Kalam argument also brings issues of the nature of time into the discussion.[23]
Craig and Sinclair have stated that the first premise is obviously true, at least more plausibly true than its negation.[24] Craig offers three reasons why the first premise is true:[25][26]
According to Reichenbach, "the Causal Principle has been the subject of extended criticism", which can be divided into philosophical and scientific criticisms.[27]
Graham Oppy, J. L. Mackie and Wes Morriston have objected to the intuitiveness of the first premise.[28][29][30] Oppy states:
Mackie affirms that there is no good reason to assume a priori that an uncaused beginning of all things is impossible. Moreover, that the Causal Principle cannot be extrapolated to the universe from inductive experience. He appeals to David Hume's thesis (An Enquiry Concerning Human Understanding) that effects without causes can be conceived in the mind, and that what is conceivable in the mind is possible in the real world.[31] This argument has been criticised by Bruce Reichenbach and G.E.M. Anscombe, who point out the phenomenological and logical problems in inferring factual possibility from conceivability.[32][33] Craig notes:
Morriston asserts that causal laws are physical processes for which we have intuitive knowledge in the context of events within time and space, but that such intuitions do not hold true for the beginning of time itself. He states:
In reply, Craig has maintained that causal laws are unrestricted metaphysical truths that are "not contingent upon the properties, causal powers, and dispositions of the natural kinds of substances which happen to exist", remarking:
A common objection to premise one appeals to the phenomenon of quantum indeterminacy, where, at the subatomic level, the causal principle ("everything that begins to exist has a cause") appears to break down.[38] Craig replies that the phenomenon of indeterminism is specific to the Copenhagen Interpretation of Quantum Mechanics, pointing out that this is only one of a number of different interpretations, some of which he states are fully deterministic (mentioning David Bohm) and none of which are as yet known to be true. He concludes that subatomic physics is not a proven exception to the first premise.[39]
The philosopher Quentin Smith has cited the example of virtual particles, which appear and disappear from observation, apparently at random, to assert the tenability of uncaused natural phenomena.[40] In his book A Universe from Nothing: Why There is Something Rather Than Nothing, cosmologist Lawrence Krauss has proposed how quantum mechanics can explain how space-time and matter can emerge from 'nothing' (referring to the quantum vacuum). Philosopher Michael Martin has also referred to quantum vacuum fluctuation models to support the idea of a universe with uncaused beginnings. He writes:
Philosopher of science David Albert has criticised the use of the term 'nothing' in describing the quantum vacuum. In a review of Krauss's book, he states:
Likewise, Craig has argued that the quantum vacuum, in containing quantifiable, measurable energy, cannot be described as 'nothing', therefore, that phenomena originating from the quantum vacuum cannot be described as 'uncaused'. On the topic of virtual particles, he writes:
Cosmologist Alexander Vilenkin has stated that even "the absence of space, time and matter" cannot truly be defined as 'nothing' given that the laws of physics are still present, though it would be "as close to nothing as you can get".[44]
Craig defends premise two using both physical arguments with evidence from cosmology and physics, and metaphysical arguments for the impossibility of actual infinities in reality.
For physical evidence, Craig appeals to:
Professor Alexander Vilenkin, one of the three authors of the Borde–Guth–Vilenkin theorem, writes:
Victor J. Stenger has referred to the Aguirre–Gratton model[48] for eternal inflation as an exemplar by which others disagree with the Borde–Guth–Vilenkin theorem.[49] In private correspondence with Stenger, Vilenkin remarked how the Aguirre–Gratton model attempts to evade a beginning by reversing the "arrow of time" at t = 0, but that: "This makes the moment t = 0 rather special. I would say no less special than a true beginning of the universe."[50]
At the "State of the Universe" conference at Cambridge University in January 2012, Vilenkin discussed problems with various theories that would claim to avoid the need for a cosmological beginning, alleging the untenability of eternal inflation, cyclic and cosmic egg models, eventually concluding: "All the evidence we have says that the universe had a beginning."[51]
However, more recently both Guth and Vilenkin have suggested that the theorem should not be used as proof of the beginning of the universe. In a film that complied many academic critics of the Kalam, Guth said the BGV theorem "means that inflation must have had a beginning, it doesn't really say that the universe must have had a beginning, but it says that the universe could not have been expanding forever" Vilenkin made a similar comment "the theorem proves that inflation must have a beginning, right, the universe as a whole - it doesn't, the theorem doesn't say that, it says that the expansion of the universe must have a beginning, right, so.. but it opens the door somewhat for alternatives"[52]
Some exotic past-eternal cosmological models, among which "Rube Goldberg cosmology" (presented by Aron Ra[53]) is not disputed by Vilenkin,[54] circumvent the physical consistency constraints on past-eternity.
On the metaphysical impossibility of actual infinities, Craig asserts:[55]
Michael Martin disagrees with these assertions by Craig, saying:
Andrew Loke has argued against the metaphysical possibility of a beginningless universe as well as that of an actual infinite existing in the real world.[59]
The possibility of infinite past has been criticized on the basis of the paradoxes this seems to enable, such as "Methuselah's Diary". A simplified version of this paradox is as follows: imagine a man that every year writes a number on a blackboard, one larger than the number already on it if there is a positive integer number, and the number 1 if there is no positive integer number; then it follows logically that the number he wrote on it the last time he did this is the age of the Universe in years (or more), which is therefore finite. One can object to this that a possibility to do something at any time does not imply a possibility to do it at all times – for comparison, any simply connected part of a spherically symmetric magnetic field is possible, but it cannot close up (and such dissonance between local and global properties has other examples – e.g. Aharonov-Bohm effect, or the BTZ black hole); or one can simply invoke the Novikov self-consistency principle, generalized to any infinite causal chains, not just looping ones.
A. Loke has proposed the paradox of "first puller" to illustrate the absurdity of infinite regress of causes: in an infinitely long train, mysteriously no locomotive is needed, as each "intermediate" train car is being pulled by the previous one - but then what is pulling the whole train? However, in General Relativity there is an exact solution called the "C-metric" which describes precisely that, a massive object being pulled (accelerated) by a "skyhook", a string under tension that starts at the object and never ends - demonstrably with no inconsistency, as it is an exact solution of the Einstein Field Equations.
Another criticism comes from Thomist philosopher Dr. Edward Feser who claims that past and future events are potential rather than actual, meaning that an infinite past could exist in a similar way to how an infinite number of potential halfway points exist between any two given points.[60]
A purely theology-internal criticism of denial of the possibility of actual infinities is that it is at odds with affirming God's omnipotence – as the latter safely includes e.g. God's ability to create an endless space. (Note that this objection has no force against atheistic philosophers skeptical of the possibility of actual infinities, such as Max Tegmark.)
Given that the Kalam cosmological argument is a deductive argument, if both premises are true, the truth of the conclusion follows necessarily.
In a critique of Craig's book The Kalam Cosmological Argument, published in 1979, Michael Martin states:[61]
Martin also claims that Craig has not justified his claim of creation "ex nihilo", pointing out that the universe may have been created from pre-existing material in a timeless or eternal state. Moreover, that Craig takes his argument too far beyond what his premises allow in deducing that the creating agent is greater than the universe. For this, he cites the example of a parent "creating" a child who eventually becomes greater than he or she.[62]
In the subsequent Blackwell Companion to Natural Theology, published in 2009, Craig discusses the properties of the cause of the universe, arguing that they follow as consequences of a conceptual analysis and of the cause of the universe and by entailment from the initial syllogism of the argument:[63]
Craig concludes that the cause of the existence of the universe is an "uncaused, personal Creator ... who sans the universe is beginningless, changeless, immaterial, timeless, spaceless and enormously powerful"; remarking upon the theological implications of this union of properties.
Craig holds to the A-theory of time, also known as the "tensed theory of time" or presentism, as opposed to its alternative, the B-theory of time, also known as the "tenseless theory of time" or eternalism. The latter would allow the universe to exist tenselessly as a four-dimensional space-time block, under which circumstances the universe would not "begin to exist":[64] The form of the Kalam he presents in his earlier work rests on this theory:
Craig has defended the A-theory against objections from J. M. E. McTaggart and hybrid A–B theorists.[65] Philosopher Yuri Balashov has criticised Craig's attempt to reconcile the A-theory with special relativity by relying on a 'neo‐Lorentzian interpretation' of Special Relativity.[66] Balashov claims:[67]
Craig has criticised Balashov for adopting a verificationist methodology that fails to address the metaphysical and theological foundations of the A-theory.[68]
It has recently been argued that a defense of the Kalam cosmological argument does not have to involve such a commitment to the A-theory.[69] Craig has since modified his view of the A-theory being necessary for the Kalam, stating that while the Kalam would need to be reformulated, "it wouldn't be fatal" on a B-theory.[70]