Argument from reason

Contemporary defenders of the argument from reason include Alvin Plantinga, Victor Reppert and William Hasker.

Thus, reasoning is trustworthy (or "valid", as Lewis sometimes says) only if it involves a special kind of causality, namely, rational insight into logical implication or evidential support.

Lewis accepted the criticism and amended the argument, basing it on the concept of nonrational causes of belief (as in the version provided in this article).

Anscombe's second criticism questioned the intelligibility of Lewis's intended contrast between "valid" and "invalid" reasoning.

Lewis didn't mean to suggest that if naturalism is true, no arguments can be given in which the conclusions follow logically from the premises.

What he meant is that a process of reasoning is "veridical", that is, reliable as a method of pursuing knowledge and truth, only if it cannot be entirely explained by nonrational causes.

In the context of ordinary life, "because he wants a cup of tea" may count as a perfectly satisfactory explanation of why Peter is boiling water.

[2] More recent critics have argued that Lewis's argument at best refutes only strict forms of naturalism that seek to explain everything in terms ultimately reducible to physics or purely mechanistic causes.

[3] So-called "broad" naturalists that see consciousness as an "emergent" non-physical property of complex brains would agree with Lewis that different levels or types of causation exist in nature, and that rational inferences are not fully explainable by nonrational causes.

Some defenders of Lewis[citation needed] claim that this objection misses the mark, because his argument is directed at what he calls the "veridicalness" of acts of reasoning (i.e., whether reasoning connects us with objective reality or truth), rather than with whether any inferred beliefs can be rational or justified in a materialistic world.

Eliminative materialism maintains that propositional attitudes such as beliefs and desires, among other intentional mental states that have content, cannot be explained by naturalism and therefore concludes that such entities do not exist.

[5] Some people think it is easy to refute any argument from reason just by appealing to the existence of computers.

[6][7][8] Since computers do not operate on beliefs and desires and yet come to justified conclusions about the world as in object recognition or proving mathematical theorems, it should not be a surprise on naturalism that human brains can do the same.

[9] Such a position seems to be bolstered by arguments from the indeterminacy of translation offered by Quine and Kripke's skeptical paradox regarding meaning which support the conclusion that the interpretation of algorithms is observer-relative.

[12] Philosophers such as Victor Reppert,[13] William Hasker[14] and Alvin Plantinga[15] have expanded on the argument from reason, and credit C.S.

Lewis never claimed that he invented the argument from reason; in fact, he refers to it as a "venerable philosophical chestnut.

"[16] Early versions of the argument occur in the works of Arthur Balfour (see, e.g., The Foundations of Belief, 1879, chap.

In Chesterton's 1908 book Orthodoxy, in a chapter titled "The Suicide of Thought", he writes of the "great and possible peril .

that the human intellect is free to destroy itself....It is idle to talk always of the alternative of reason and faith.

"[17] Similarly, Chesterton asserts that the argument is a fundamental, if unstated, tenet of Thomism in his 1933 book St. Thomas Aquinas: "The Dumb Ox": Thus, even those who appreciate the metaphysical depth of Thomism in other matters have expressed surprise that he does not deal at all with what many now think the main metaphysical question; whether we can prove that the primary act of recognition of any reality is real.

58–59), Richard Taylor's Metaphysics (Englewood Cliffs, NJ: Prentice Hall, 3rd ed., 1983, pp.

104–05), and J. P. Moreland's Scaling the Secular City: A Defense of Christianity (Grand Rapids, MI: Baker, 1987, chap.