Thursday, June 28, 2012

Slight Variation of the Argument from Reason

Inspired by Reppert's argument in C.S. Lewis's Dangerous Idea on pp. 57-58:

1. No belief is rationally inferred if it can be fully explained in terms of non-rational causes. (Premise)

2. If naturalism is true, then all beliefs can be fully explained in terms of non-rational causes. (Premise)

3. Hence, if naturalism is true, then no belief is rationally inferred. (From 1 and 2)

4. Beliefs can be rationally inferred. (Premise)

5. Therefore, naturalism is false. (From 3 and 4)

I modified Reppert's "materialism" to my own rendering of "naturalism."  I also simplified (4) and (5).

The naturalist is likely to accept (1) and (4), but will almost certainly deny (2).  After all, aren't our minds rational causes?  In a word, yes.  It's true that our minds are rational causes, but that's not quite what the argument is getting at.  What the argument from reason stresses is that our minds are the result of some type of process.  That process (e.g. evolution) either includes rational causes or strictly non-rational causes.  It's the theist who says that evolution includes rational causes.  It's the atheist who is committed to the view that only non-rational causes are at work in the formation of our minds.

With that said, why think our minds generally produce true beliefs if they are the mere result of non-rationality?  If one wishes to bite the bullet and say our minds generally don't produce true beliefs, contrary to (3), then the belief that our minds are only the result of non-rationality is itself most likely not true!

This latter aspect is what Alvin Plantinga focuses on in his Evolutionary Argument Against Naturalism (EAAN).  The claim isn't that evolution is false, but that naturalism is inconsistent with evolution and rational minds (Plantinga's term is "cognitive faculties").  Thus, the truth of evolution implies the falsity of naturalism.


  1. "The naturalist is likely to accept (1) and (3), but will almost certainly deny (2)."

    Really? What 'naturalists' do you have in mind?

    But, really, like nearly everyone else (including Reppert), you're missing the point -- the argument isn't about the -ists, it's about the -ism. That is, it matters not a whit that this or that 'athe-', er, 'naturalist' denies some logical entailment of 'ath-', er, 'naturalism'. What matters is the content and logical entailments of 'natralism'.

  2. Ilion, I meant to say that the naturalist is likely to accept (1) and (4). I've made the correction.

    I agree, though, that naturalism is the key. I think what you and I and Reppert have in common is that we all think the individual naturalist's belief that beliefs are rationally inferred is inconsistent or otherwise undermined by his naturalism.

  3. The naturalist could object to premise 1. Assume a deterministic + naturalistic universe. Person A is "programmed" (via genetics/environment/evolution/etc) to behave via rational principles (such as updating their beliefs based on evidence, etc). Person B is "programmed" to behave via irrational principles. One could still say that A is inferring rationally, whereas B is not. In other words, the naturalist can simply say that purely mechanical chain of events CAN be said to infer rationally/irrationally.

  4. Naturalism is the new way for humans to believe they are the center of the universe, or in other words special... They want to believe they are a great intelligence born out of the center of a random number generator that always existed for no other reason than that it was a natural fountain blowing out numbers like the matrix and somehow out of the middle of that great stream of water flow it brilliantly and randomly produced a whole play that had intense meaning and music and rainbows and color and movies and love and sex and everything else in between.

  5. Also your comment spam protection is too hard to work through!!! took me way too long to figure it out.

  6. Sorry it took so long to get your comments published! I was out of town for a few days.