Originally posted by twhitehead
So although you stated it as if it followed from your argument, in reality it doesn't follow from your argument and you just take the word of Plantinga?
At best one can say that the probability of our inheriting reliable cognitive faculties is inscrutable. The question then is, is it reasonable to accept the deliverances of your cognitive faculties lly fail to see how any of this leads to the OPs claim that a naturalist must presuppose God.
So although you stated it as if it followed from your argument, in reality it doesn't follow from your argument and you just take the word of Plantinga?
The pages I refer you to contain the probability calculus that you're looking for, which you are more than welcome to assign your own values to. On the contrary, I'm taking Hume's word for it: "Our experience, so imperfect in itself and so limited both in extent and duration, can afford us no probable conjecture concerning the whole of things" (
Dialogues concerning Natural Religion, p. 45). When you take God out of the equation, the probability that our cognitive faculties are aimed at truth is inscrutable at best.
Well then one should not choose to rely on their cognitive faculties based purely on a probability argument based on their origins.
What other recourse is there for the rational naturalist?
Maybe it is pure chance that evolution has led to cognitive faculties that are capable of producing true beliefs, but that in no way suggests that they are any less capable of doing so than cognitive faculties that are aimed at producing true beliefs.
I agree, but this isn't the issue. It may well be that evolution has produced in us cognitive faculties capable of producing true beliefs (most of us probably agree that our cognitive faculties are indeed reliable), but
on naturalism it is impossible to determine with a sufficient degree of certainty that this is the case. Naturalism is self-defeating because it calls into serious question the reliability of the very cognitive instrument which it depends on for its affirmation.
And lastly, I totally fail to see how any of this leads to the OPs claim that a naturalist must presuppose God.
In order to affirm naturalism (that the world exists, persists and evolves without anything like God or gods) one must presuppose cognitive faculties aimed at true beliefs, the likeliness of which naturalism itself casts sufficient doubt upon to serve as a defeater. Since naturalism is self-defeating in this regard, in order to affirm naturalism one must appeal to a world-view wherein cognitive faculties are aimed at producing true beliefs—namely, the theistic world-view (as described earlier). God's existence is implied in a theistic world-view. Therefore, in order to affirm naturalism one must presuppose God's existence.