Tuesday 12 August 2008

is disbelief in god irrational?

I don't believe that philosophy can prove God, certainly not to someone who wants to disbelieve, any more than it can disprove God's existence. But philosophers still address the question.

Alvin Plantinga is an eminent American philosopher who has long been a champion of an argument that (in summary) goes like this .....

Let us start by assuming there is no God and this natural world is all there is. Then our brains have evolved through natural selection alone. Natural selection works by certain behaviour increasing the probability of survival, which means more of the genes which lead to that behaviour are passed on to the next generation.

Thus, on the assumption we started with, the brain has evolved to choose behaviour that increases our chances of survival, but there is no reason to believe that it has also evolved ways of thinking about more abstract matters that are reliable. Thus our reasoning may be true in some circumstances and false in others, and we cannot trust it.

But it is our reasoning that has suggested the conclusion that no God exists, so the initial assumption is undermined. Plantinga concludes that it is thus irrational to assume a naturalistic belief in the first place.

Of course the argument is criticised by some other philosophers and dismissed by some scientists, but it seems to me to have force. Read a recent discussion of the argument by Plantinga, a discussion of some of the objections, and a discussion of some of the implications.

7 comments:

  1. One problem that I have with this argument is that IF only naturalistic evolution has taken place then our belief in God should also not be trusted.

    ReplyDelete
  2. Jules

    Thanks for your comment. Yes, of course that would be true. And on that assumption belief in God would be false as well as not to be trusted. But that just reinforces the main point of the argument, that if naturalism is true, we can't trust our thinking - so we need a new assumption before we can think reliably about such matters.

    In a sense it's a reductio ad absurdum type of argument.

    ReplyDelete
  3. unkle e is correct, it is a reductio ad absurdum argument. Plantinga's argument is:

    1) Assume both evolution and naturalism is true.
    2) Show that if 1) is true, then our cognitive faculties shouldn't be trusted.
    3) Conclude that both evolution and naturalism can't both be true (that is, either one or the other or both is false).

    The fact that he assumes 1) in his argument doesn't mean that, as Jules said, "our belief in God should also not be trusted." All it means is that 1) is wrong if his argument is a good one.

    ReplyDelete
  4. All it means is that 1) is wrong if his argument is a good one.

    What I got out of it was that if his argument is correct, 1) may be true, but we can't assert its truth, because if we try to justify 1) rationally we end up with a "defeater" for all rational belief, including 1).

    The key bit is here: but there is no reason to believe that it has also evolved ways of thinking about more abstract matters that are reliable.

    I'd say that runs against common sense, but I'm not quite sure how I'd prove it conclusively. What it may come down to, until someone comes up with a proof, is a simple assumption that knowing the truth has value in evolutionary terms. Plantinga doesn't assert that this is false, just that there's no reason to think it's true. But since assuming the truth has value makes the world make sense, I'm going to go with it until someone can prove I shouldn't :)

    ReplyDelete
  5. Myron,

    Thanks for dropping by and making a comment.

    I think the idea, implicit in naturalism, that we have no freewill, and our choices are simply the result of chains of cause and effect which happen to run through our brains, is also against common sense, yet many naturalists say they believe it.

    The point is, naturalism claims to be built on rationality, yet if your response is correct, we can only take that rationality "on faith" - it seems common sense. I don't think that's good enough.

    Or would you not criticise someone who said: "I believe in God, it seems like common sense"?

    I think these issues are more difficult and more important that you make out.

    ReplyDelete
  6. The point is, naturalism claims to be built on rationality, yet if your response is correct, we can only take that rationality "on faith" - it seems common sense. I don't think that's good enough.

    Or would you not criticise someone who said: "I believe in God, it seems like common sense"?


    I wouldn't criticize that, necessarily. My reaction would depend on if the image of God the person had was one where they could explain to me how it was commmon sense. If I was satisfied with the explanation, I'd leave it at that. But if they claimed something made sense to them that didn't make sense to me (the usual case) I would continue to question until either their perspective made sense to me, they came to see it didn't make sense, or they left the conversation.

    While it would be ideal to prove or disprove God, naturalism, and various other approaches to answering questions concerning why we are the way we are, we don't have enough evidence to do so, and I don't 100% trust our cognitive facilities to do a good job of descerning correct from incorrect claims. So I am forced to an ad-hoc position, evaluating people's truth claims as best I can while realizing my methods aren't perfect. Given I've spent so much time and effort looking, I'm skeptical of people who say they've found answers they are absolutely certain about, and I would question that certainty whether it's claimed about naturalism or God.

    ReplyDelete
  7. I think the idea, implicit in naturalism, that we have no freewill, and our choices are simply the result of chains of cause and effect which happen to run through our brains, is also against common sense, yet many naturalists say they believe it.

    I don't see it as being against common sense. In fact, if the statement that "God has a plan" is true, and yet God isn't constantly intervening to fix our mistakes (which we see very little evidence of) then the future would have to be predetermined. Setting aside whether God has a plan or not, the evidence seems to point to humans not really being distinct from animals, and yet proponents of free will would not say that animals can change the future by their actions.

    I'm content with the fact that for all practical intents and purposes we have free will, because we don't know the future, but we do know our actions will affect it. The insistence that we're somehow unlike everything else in the universe seems counter-intuitive to me.

    ReplyDelete

Note: only a member of this blog may post a comment.