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 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.
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. 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".
Form of the argument
The most prominent form of the argument, as defended by William Lane Craig, states the Kalam cosmological argument as the following syllogism: Everything that begins to exist has a cause. The universe began to exist. Therefore, the universe has a cause.
Given the conclusion, Craig appends a further premise and conclusion based upon a philosophical analysis of the properties of the cause of the universe:
If the universe has a cause, then an uncaused, personal Creator of the universe exists who sans (without) the universe is beginningless, changeless, immaterial, timeless, spaceless and enormously powerful.
Therefore, an uncaused, personal Creator of the universe exists, who sans the universe is beginningless, changeless, immaterial, timeless, spaceless and enormously powerful.
Referring to the implications of Classical Theism that follow from this argument, Craig writes:
"... transcending the entire universe there exists a cause which brought the universe into being ex nihilo... our whole universe was caused to exist by something beyond it and greater than it. For it is no secret that one of the most important conceptions of what theists mean by 'God' is Creator of heaven and earth."
Historical background
The Kalam cosmological argument is based on the concept of the prime-mover, introduced by Aristotle, and entered early Christian or Neoplatonist philosophy in Late Antiquity, being developed by John Philoponus. Along with much of classical Greek philosophy, the concept was adopted into medieval Islamic tradition during the Islamic Golden Age, where it received its fullest articulation at the hands of Muslim scholars, most directly by Islamic theologians of the Sunni tradition.
Its historic proponents include Al-Kindi, Al-Ghazali, and St. Bonaventure.
One of the earliest formulations of the Kalam cosmological argument in the Islamic philosophical tradition comes from Al-Ghazali, who writes:
"Every being which begins has a cause for its beginning; now the world is a being which begins; therefore, it possesses a cause for its beginning."
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). 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. 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:
"According to the hypothesis under consideration, it has been established that all the beings in the world have a cause. Now, let the cause itself have a cause, and the cause of the cause have yet another cause, and so on ad infinitum. It does not behove you to say that an infinite regress of causes is impossible."