 Philosophers employ diverse classifications of the cosmological arguments. Swinburne distinguishes inductive from deductive versions. Craig distinguishes three types of deductive cosmological arguments in terms of their approach to an infinite regress of causes. The first, advocated by Aquinas, is based on the impossibility of an essentially ordered infinite regress. The second, which Craig terms the kalām argument, holds that an infinite temporal regress of causes is impossible because an actual infinite is impossible, and even if it were possible it could not be temporally realized. The third, espoused by Leibniz and Clarke, is overtly founded on the Principle of Sufficient Reason (Craig 1980: 282–83), although it appears that all versions use some form of that principle. Craig notes that the distinction between these types of arguments is important because the objections raised against one version may be irrelevant to other versions. So, for example, a critique of a particular version of the Principle of Sufficient Reason (PSR), which one finds developed by William Rowe or Richard Gale, might not be telling against the Thomistic or kalām versions of the argument. Another way of distinguishing between versions of the argument is in terms of the relevance of time to the argument. In Aquinas’s version, consideration of the essential ordering of the causes or reasons proceeds independent of temporal concerns. The relationship between cause and effect is treated as real but not temporal, so that the first cause is not a first cause in time but a sustaining cause (Siniscalchi 2018: 691). In the kalām version, however, the temporal ordering of the causal sequence is central, introducing issues of the nature of time into the discussion.