Thanks for the response. I was wondering what you actually thought of Plantinga's argument.
Coming back to Dusman's argument, he was talking about rationality. I took that as proper function rationality. And Plantinga does not believe that N&E is a proper-function rationality defeater against R. Suppose I say that the atheist does not have animal knowledge of ULL. It does not mean that she does not have justification for ULL. It may be that she is just short of warrant. But short of warrant does not necessarily mean that she is not justified.
Now here is an example where an atheist may still have animal knowledge of ULL. Suppose that S comes to believe in ULL through virtue (I'm using virtue epistemology rather than proper function but you can substitute whatever). And now we show that P(ULL/N&E) is low. It does not necessarily mean that S does not have animal knowledge of ULL. N&E may even be a defeater for S, but it may not take away justification nor knowledge. Suppose that the way S forms ULL, with regards to evidence (used broadly), she has .8 degree of belief or justification towards ULL. Given E at t1, her justification is .8. Now suppose N&E is low given R. It is a defeater. But suppose that S also has nonpropositional evidence for ULL (see Bergmann's article in Naturalism Defeated?). E at t2 would include N&E, but it does not necessarily mean that S has no justification for ULL at all. It may be that given new evidence, N&E, she just has to lower her degree of credence or belief to, say, .56. But it may be that .56 is just enough for knowledge. So S can have knowledge. In other words, if N&E is a defeater, it may simply show that S has a lesser degree of justification. It does not mean she is not justified or irrational, but her degree of justification or rationality just dropped.
What do you think?
Quote Taken from here
By way of reply,
1. I recently posted about "what [I] actually thought of Plantinga's argument." See Round 1, Round 2, and Round 3.
2. I won't comment as to how Dusman was using 'rationality,' since I'm not sure. There's many subsets, i.e., alethic rationality, internal rationality, etc. Proper function rationality determines what we should do when confronted with one of these cases of irrationality. So, his point may have been more specific.
3. Plantinga does believe that EAAN gives the reflective naturalist a "kind of" proper function rationality defeater - a Humean defeater (see ND? p.209-211).
4. "Short of warrant" does not necessarily mean "unjustified," correct. But, the reflective naturalist has a defeater for his belief that he has "done his duty." Furthermore, the reflective naturalist has no reason to believe R. Similarly, the believer who accepts that his belief in God is the product of wish fulfillment, and beliefs finding their source in the cognitive faculties responsible for producing wish-fulfillment are not aimed at truth but some other purpose, has a defeater for his belief in God. This person's belief in God has no epistemic justification, then. The same for the reflective naturalist, then. Before reflecting, he may be justified, but not after.
5. Even if EAAN didn't take away "animal knowledge," the naturalist would still have a defeater for his beliefs, and so EAAN would still be pretty forceful.
6. Relying on Bergmann's idea of R being properly basic, and so it's a defeater-deflector for EAAN, seems to miss the point of EAAN. Of course proper function would demand continued belief in R, but this is not because this portion of your cognitive faculties are aimed at truth, but, rather, at the avoidance of cognitive disaster. A person S may be in a situation - say, lost in a snow storm on top of a mountain - and S may see a ridge that S thinks could be leaped to. Based on perception, this belief is basic to S. But, S would not have thought this if S were not in this survival situation. So S maintains this belief that the chasm is able to be jumped. Proper function requires this belief to be maintained. The optimistic overrider has kicked in. But the faculties governing this have some other virtue in mind - survival rather than true belief. In normal, reflective situations, S would not form said belief.
Or, suppose S ingests agent XX, a hallucinogenic drug, producing hallucinations in 90% of those who take XX. Proper function would require assuming R so as to avoid cognitive disaster. So, S has powerful inclinations to continue on in belief in R, even though S has come to believe that P(R / XX) is low or inscrutable, and S may take it in a basic way, but of course these powerful inclinations don't count as evidence for R. S would have this inclination whether she was in or out of the lucky 10%.
7. One can only use Bergmann's position that R has non-propositional evidence for it, raising the probability thesis, in cases of an unreflective naturalist. But, can the reflective naturalist have this? Well, if so, then R has warrant for him only if R is produced by proper functioning cognitive faculties successfully aimed at truth. But his beliefs are only successfully aimed at truth if they are reliable, and this is precisely what's in question. And, just to say that he has a strong inclination to believe R, doesn’t get him where he wants (see (6) above). And, if he assumes N & E, he has no reason to assume that his beliefs are aimed at truth. So non-propositional evidence doesn't help S.
8. If all it took was that a belief B could not be defeated D because B had non-propositional evidence, then it would appears that basic beliefs could not be defeated. Say that you go inside a widget producing factory. You see the widgets, and they appear red to you. The belief is formed by your senses, which proper function demands you believe are reliable, and hence the belief is basic. But, the shop manager, and close friend, tells you that the widgets have a red light illuminating them so as to detect otherwise unnoticeable defects in the widgets. He says that there are actually very few red widgets coming down the assembly line. It would appear that your basic belief was defeated that what you were seeing was a red widget because the probability that you were seeing a red widget was low.
Or, say that S comes to believe that she is a brain-in-the-vat (BIV). Further, so has no reason to believe that the Alpha Centaurian super scientists care whether she has mostly true beliefs or not. So, she believes P (R/ BIV) as low or inscrutable. Doesn't she have a defeater for R, no matter how strongly she continues to assume R on an every day basis. After all, the Alpha Centaurians needs to see her in every day life and so have constructed her to continue to believe R, and act as if R, because to not act that way would lead her into cognitive despair. But, when she reflects on her thoughts, she quires a defeater for R, and so gives it up. Same with the naturalist.
9. Lastly, S is irrational because proper function for internal rationality that S give up one of S's beliefs: R v N&E. If S came to believe that she had ingested agent XX - which caused hallucinations in 90% of those who took it, and S also held to R, proper function would require S to drop R. Or, say that S believed his head made of glass, and believed that he could play football without a helmet, then he would be internally irrational to not give up one of the beliefs (if, following Alston, one wishes to say that S should drop N&E rather than R, I still think that gets you to ~R, but just takes the long way. For without a story on the purpose of your cognitive faculties, how they got here, or anything, S should remain agnostic A about R, and so P(R/ A) would be inscrutable, and the defeater for R has not left. Though she still might act as if R, upon reflection, rationality demands R to be dropped. We would call someone who believed both of the above propositions, irrational. If S is in a similar situation with P(R / N&E), then S is irrational for holding to R in the Humean and alethic-rationality way.