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I learned Plantinga's Evolutionary Argument Against Naturalism in the following form:

1. The probability for the reliability of cognitive faculties conditional on naturalistic evolution, P(R|N&E), is low or inscrutable.
2. If P(R|N&E) is low or inscrutable, then the believer in N&E has an undefeatable defeater for R (that one's cognitive faculties are reliable).
3. If the believer in N&E has an undefeatable defeater for R, he/she has an undefeatable defeater for all beliefs, including N.

Therefore, it is irrational for the believer in N&E to believe in N. This concludes the self-defeating nature of naturalism Plantinga points to.

My question is regarding premise 2.

In Warrant and Proper Function, on page 228, right after Plantinga presents A Preliminary Argument against Naturalism, he says suppose you take P(R|N&E) to be low and that you think your cognitive faculties are reliable; then you have a straightforward probabilistic argument against naturalism.

I'm confused because premise 2 suggests we have an undefeatable defeater for all our beliefs; that is, all our beliefs are rendered irrational to accept. But, he starts out by saying "suppose you think your cognitive faculties are reliable".

1. Isn't there a contradiction here?
2. Sure P(R|N&E) is low or inscrutable, but that doesn't necessarily mean our cognitive faculties are unreliable. It would imply that if that piece of information was all we knew, but in general, we know a lot more to reasonably say our cognitive faculties are reliable. So I don't see how premise 2 is even remotely logical.

I learned Plantinga's Evolutionary Argument Against Naturalism in the following form:

1. The probability for the reliability of cognitive faculties conditional on naturalistic evolution, P(R|N&E), is low or inscrutable.
2. If P(R|N&E) is low or inscrutable, then the believer in N&E has an undefeatable defeater for R (that one's cognitive faculties are reliable).
3. If the believer in N&E has an undefeatable defeater for R, he/she has an undefeatable defeater for all beliefs, including N.

Therefore, it is irrational for the believer in N&E to believe in N. This concludes the self-defeating nature of naturalism Plantinga points to.

My question is regarding premise 2.

In Warrant and Proper Function, on page 228, right after Plantinga presents A Preliminary Argument against Naturalism, he says suppose you take P(R|N&E) to be low and that you think your cognitive faculties are reliable; then you have a straightforward probabilistic argument against naturalism.

I'm confused because premise 2 suggests we have an undefeatable defeater for all our beliefs; that is, all our beliefs are rendered irrational to accept. But, he starts out by saying "suppose you think your cognitive faculties are reliable".

1. Isn't there a contradiction here?
2. Sure P(R|N&E) is low or inscrutable, but that doesn't necessarily mean our cognitive faculties are unreliable. It would imply that if and only if that piece of information was all we knew, but in general, we know a lot more to reasonably say our cognitive faculties are reliable. So I don't see how premise 2 is even remotely logical.

• As an example of what I mean here: consider I draw a 10 of diamonds. I can see it. But I also note the deck is fair so the P(10 D|fair deck)<<1. But, it's false for me to claim that it is irrational to believe I drew a 10 of diamonds because the conditional probability is so low. No, I see that I did in fact draw the 10 of diamonds.

I learned Plantinga's Evolutionary Argument Against Naturalism in the following form:

1. The probability for the reliability of cognitive faculties conditional on naturalistic evolution, P(R|N&E), is low or inscrutable.
2. If P(R|N&E) is low or inscrutable, then the believer in N&E has an undefeatable defeater for R (that one's cognitive faculties are reliable).
3. If the believer in N&E has an undefeatable defeater for R, he/she has an undefeatable defeater for all beliefs, including N.

Therefore, it is irrational for the believer in N&E to believe in N. This concludes the self-defeating nature of naturalism Plantinga points to.

My question is regarding premise 2.

In Warrant and Proper Function, on page 228, right after Plantinga presents A Preliminary Argument against Naturalism, he says suppose you take P(R|N&E) to be low and that you think your cognitive faculties are reliable; then you have a straightforward probabilistic argument against naturalism.

I'm confused because premise 2 suggests we have an undefeatable defeater for all our beliefs; that is, all our beliefs are rendered irrational to accept. But, he starts out by saying "suppose you think your cognitive faculties are reliable". Is he implying that we should assume all our beliefs formed prior to learning that we have evolved through N&E are reliable? Otherwise, I have a hard time understanding his argument because we get into a circular argument--if I believe in premise 2, then I believe my beliefs are unreliable, including the very belief of premise 2. How does Plantinga prevent this circular self-defeating criticism?

I learned Plantinga's Evolutionary Argument Against Naturalism in the following form:

1. The probability for the reliability of cognitive faculties conditional on naturalistic evolution, P(R|N&E), is low or inscrutable.
2. If P(R|N&E) is low or inscrutable, then the believer in N&E has an undefeatable defeater for R (that one's cognitive faculties are reliable).
3. If the believer in N&E has an undefeatable defeater for R, he/she has an undefeatable defeater for all beliefs, including N.

Therefore, it is irrational for the believer in N&E to believe in N. This concludes the self-defeating nature of naturalism Plantinga points to.

My question is regarding premise 2.

In Warrant and Proper Function, on page 228, right after Plantinga presents A Preliminary Argument against Naturalism, he says suppose you take P(R|N&E) to be low and that you think your cognitive faculties are reliable; then you have a straightforward probabilistic argument against naturalism.

I'm confused because premise 2 suggests we have an undefeatable defeater for all our beliefs; that is, all our beliefs are rendered irrational to accept. But, he starts out by saying "suppose you think your cognitive faculties are reliable".

1. Isn't there a contradiction here?
2. Sure P(R|N&E) is low or inscrutable, but that doesn't necessarily mean our cognitive faculties are unreliable. It would imply that if that piece of information was all we knew, but in general, we know a lot more to reasonably say our cognitive faculties are reliable. So I don't see how premise 2 is even remotely logical.