Teleological design arguments from analogy (Paley) and from spatial order and regularity, the cosmological argument from causation and contingency (the Kalam and Aquinas' first three Ways and Leibniz on sufficient reason), and the objections of Hume and Kant including the limits of analogy and the fallacy of composition.

What this dot point is asking

AQA wants you to explain the a posteriori arguments for God's existence: teleological (design) arguments from analogy and from spatial order, and cosmological arguments from causation and contingency, with their main proponents, and to evaluate the objections, chiefly Hume's and Kant's.

Design (teleological) arguments

It is worth separating two strands the spec lists. Design qua purpose (Paley) stresses the adaptation of parts to ends, the way an eye is structured for seeing. Design qua regularity stresses the bare orderliness of nature, the fact that the universe obeys simple, stable laws at all. The second is harder for Darwinian natural selection to deflate, because evolution presupposes law-governed regularity rather than explaining it; this is why modern defenders such as Swinburne shift the argument from biological adaptation (where selection offers a rival explanation) to the existence of the laws themselves, often combined with fine-tuning, the observation that the physical constants fall within the narrow range that permits life. The design argument is best read as an inference to the best explanation: order plus apparent purpose is more probable given a designer than given chance, so it raises the probability of theism rather than proving it deductively.

Cosmological arguments

Hume's objections (mainly to design)

• Weakness of the analogy. The universe is not very like a machine such as a watch; it is at least as like an organism, which grows rather than being made.
• The inference is unwarranted. From a single universe we cannot generalise as we do for watches; we have no experience of universes being made.
• It does not deliver the God of theism. Even granting a designer, the argument does not show the designer is one, infinite, perfectly good or even still existing; the world's flaws suggest an imperfect or apprentice designer.
• Alternative explanations. Order could arise without design, for example through chance over time (anticipating natural selection), the Epicurean hypothesis.

Objections to the cosmological argument

• Hume on causation and the fallacy of composition. We cannot assume the universe as a whole needs a cause just because its parts do (that may commit the fallacy of composition); and a necessary being whose non-existence is a contradiction may be incoherent.
• Kant. The cosmological argument secretly relies on the discredited ontological argument when it claims a being whose existence is necessary, so it inherits the same flaw; and the categories such as causation apply only within experience, not beyond it to the universe as a whole.
• The possibility of infinite regress or a brute fact. Why must the causal series have a first member, and why could the universe not simply be a brute, unexplained fact? Russell pressed exactly this in his debate with Copleston: "the universe is just there, and that's all", denying the principle of sufficient reason that the cosmological argument needs.
• Rejecting the principle of sufficient reason. If not every fact has an explanation, then the demand for a reason for the whole series of contingent things simply lapses; the theist must defend the principle, not assume it.

A careful evaluation separates the two argument families because the objections do not transfer. Hume's analogy objection bites hard against design but is irrelevant to the cosmological argument, which uses no analogy. Conversely the fallacy of composition and the attack on the principle of sufficient reason target the cosmological argument and leave design untouched. The strongest line for the theist is that even if neither argument proves God deductively, together they may raise the probability of theism as the best explanation of both the existence and the order of the universe; the strongest line for the critic is that "God" is no more self-explanatory than a brute universe, so the arguments merely relocate the mystery.