Sunday, September 2, 2012

Alvin Plantinga on warrant for belief, naturalism, and evolution

Notre Dame philosopher Alvin Plantinga is one of the most prominent living Christian philosophers. Perhaps his most famous argument against naturalism/atheism is his evolutionary argument against naturalism.

He argues that if naturalism and evolution are true-- if man is a mere material creature evolved by Darwinian mechanisms-- then our rational faculties are evolved for adaptation, not for truth-finding. Our beliefs are evolved in such a way that they help us reproduce more successfully. There is no inherent link in the evolutionary scheme between our ability to reason and our ability to ascertain truth. Evolution cares not at all about abstract truth. Therefore, if we believe that naturalism and evolution are true, we have no warrant to assert that our belief is true. We merely have warrant to assert that our belief in naturalism and evolution are adaptive.

Belief in naturalism and evolution is self-defeating. If naturalism and evolution are true, you have no warrant to believe they're true.

The argument is simple and is obviously valid. Here's Plantinga explaining it. He discusses it at about 2:50 into the interview. He also discusses his own belief in God, and he discusses the meagre arguments put forth by the New Atheists.






H.T. Jerry Coyne

49 comments:

  1. Michael,

    I 'loved' his argument that if there are two possilities for something, then the chances of either being true is 50:50. So let's see. Either you're a neurosurgeon or you're not. The chances of you not being a neurosurgeon is therefore exactly 50%. Evolution didn't give me accurate senses, just adaptive ones. So if I look on the Internet and 'see' you listed on the faculty of your university and read your entry on Wikipedia, I can't trust my senses, and it doesn't confirm my materialistic belief that you're a neurosurgeon, and therefore I'm better off trusting my god-given sense that you're not.

    Was that his argument?

    I loved his his comment that the philosophical arguments for the existence of God are very weak .... Pause, thinks 'shit, I've made a lot of them myself', and immediately backtracks.

    The arguments the new atheists are making for the non existence of god(s) are exactly the same ones the old atheists were making.

    ReplyDelete
    Replies
    1. His argument is simple. If evolution and materialism are true, our faculty for reason is evolved for adaptation. It is not evolved specifically for discernment of abstract truth, unless a specific abstract truth happens to be adaptive as well. But there is no necessary connection between adaptation and abstract truth.

      Thus, if we believe evolution and materialism to be true, then we must also believe that we have no warrant to trust our judgement to discern truth.

      It's a simple clear argument, and it's obviously valid. Variants of it have been made by many people (CS Lewis made the argument).

      The only way you would have warrant to believe that evolution and materialism are true is if you can demonstrate that discernment of abstract truth is reliably linked to reproductive advantage.

      Good luck.

      Delete
    2. Mike,
      Indeed.
      If there is only matter and the adaptability of that matter into complex reproducing forms we call 'life' and 'emergent phenomena' , then 'truth' is completely illusory. Truth dies along with morality and any real form of objectivity.
      If truth is illusory, then what how can anything - let alone ideas of materialism/naturalism that support these notions- really be true?
      The whole concept is an exercise in avoidance and/or dishonesty and is clearly a paradox:
      'The only truth is that there is no truth' is obviously a LIE.
      Perhaps a hint at the origins of such thought?

      Delete
    3. @crus:

      Materialism is a lie from the father of lies.

      Delete
    4. Agreed, Mike.
      Part of the original lie, really.
      I tend to think of materialism as a form of self limiting or even voluntary philosophical myopia...or maybe cataract would be a better description? Either way the affliction, I tend to imagine, is one of laziness.
      As i get older and see the market created to enhance and promote the nihilistic views that flow from materialist thought even to children , I begin to see something far more insidious than mere laziness or even shallow mindedness.

      Delete
    5. Utlimately, materialism, and atheism, is the denial that one's own self is real.

      Delete
  2. Bach,
    No... Wow.
    Not even close.
    You need to defog those goggles and watch the video again.
    The idea is a little more complex than what you have suggested.
    It is about self refutation.
    Naturalism, Prof Plantinga suggests, is about adaptive behaviours. Beliefs (including 'worldviews' like naturalism) are only relevant when they influence behaviour in an adaptive or counter adaptive fashion (positively or negatively). hence your 50/50.
    In short naturalism (as a belief system or 'worldview') is not about getting to the truth of matters, it is avoiding the whole question of truth and with it a great deal of reality.

    By extension, I think the suggestion of the 'idea' (as the prof puts it) is that naturalism is not a means to address the broad spectrum of truth, purpose, or meaning that is existence and is therefore, at best, a means to focus on adaptive behaviours and is, at it's worst, often used to hide from the broad and more interesting questions that face us all by being used as a sort of substitute religion or philosophy - as within the "New Atheist' movement.

    Nothing to do with God's will, Wikipedia, or Neurosurgery in Western New York.

    ReplyDelete
  3. Am I the only one struck by the irony that a Christian philosopher is arguing that we can’t trust our beliefs because of evolution. I submit the crazy unsupported crap that Christians believe as exhibit A.

    If the flip-side that if we didn’t evolve and we can trust our beliefs, it begs the question why so relatively few of the billions of people on this planet don’t see the truth as reveled by Christianity.

    Keep your philosophy, I’ll stick with science, which deals less with “truth”, and more with mathematical models that allow predictions to be made, tested, and verified, and that allow us to develop ever more accurate descriptions of the universe and everything in it.

    -KW

    ReplyDelete
    Replies
    1. Modern theoretical science is wholly a product of Christian civilization, and depends utterly on the Christian understanding of creation and God.

      Atheist civilizations-- and we've had quite a few of them over the past century-- have advanced only one science-- mortuary science.

      Atheism has contributed nothing of value to science. "Shit happens because of no ultimate reason" is hardly a basis for understanding nature.

      Atheists are parasites, living off the bounty of Christian civilization and denying their debt to Christianity for creating modern theoretical science.

      Delete
    2. Atheism is the natural result of a materialistic world view, the view that underpins all of science. I would be more inclined to say that the materialistic world view took root in the west despite Christianity.

      -KW

      Delete
    3. @KW:

      [Atheism is the natural result of a materialistic world view,]

      You've got it backwards. The materialistic world view is the natural result of atheism.



      [a materialistic world view, the view that underpins all of science. I would be more inclined to say that the materialistic world view took root in the west despite Christianity.]


      You'd be wrong to say so. The materialistic world view is an incoherent philosophical mistake, and has nothing to do with science.

      Science depends critically on inferences that have no basis in materialism. Materialism offers no explanation for rationality in nature, for predictability in nature, for the existence of truth that transcends human opinion, for intelligible principles in nature which are inherently immaterial, for mathematics and logic, neither of which are material.


      Delete
    4. You are crazy. Science is based on materialistic assumptions. Science assumes there are no capricious forces acting in unpredictable ways. It wouldn’t be science otherwise.

      -KW

      Delete
    5. @KW

      Materialism asserts (to the extent that it asserts anything) that all that exists is matter/energy.

      Is mathematics matter or energy? Logic? Truth?

      Is the assertion that all is matter/energy itself matter or energy?

      Materialism falls victim to the same self-refutation that ended its more pretentious sibling-- positivism.

      Materialism isn't really an ideology. It's an intellectual fashion, worn by non-intellectuals.

      Delete
    6. Is mathematics matter or energy?

      Yes. Mathematics is a logical construct in human brains, or written in material form. Your thoughts are chemical activity in your brain - in other words, matter and energy in action.

      Delete
    7. Can somebody post a picture of a sample of pure numbers? Maybe a phial or beaker of 'ones' (not the yellow type - the actual number). Could somebody provide me with a physical example of a number greater than one. Of course, I don't mean two apples - that is just evidence of apples.
      I want to see the 'two' please.
      Once you have managed that, perhaps an example of negative integers?
      Thanks.
      :)

      Delete
  4. Plantinga's argument is not "obviously true". It is obviously stupid. The chance of any belief being true is not 50/50. The contortions Plantinga has to go to in order to try to support this unfounded assertion is evidence of the impoverished nature of the argument. The ape running away from a predator who climbs a tree, according to Plantinga, might think that the beast is trying to eat him, but is equally likely to think that it is just some sort of fun game. That is so clearly untrue that it is hilarious that someone would make it the crux of their argument.

    Plantinga even undermines his own argument by saying the probability (which he pulls out of his ass, since one cannot determine probabilities after the fact) that the ability to tell the truth from nontruth is low or (in his own words) inscrutable. Inscrutable means "unknowable". In short, his argument, to dignify his drivel as such, admits that it is impossible to determine the probability that he is trying to determine. But then, having said that the probability is unknowable, he tries to backtrack and claim that he can figure it out using made up probabilities pulled out of his ass.

    No one in philosophical circles takes Plantinga's arguments about evolution and naturalism seriously. He is a joke.

    ReplyDelete
    Replies
    1. @anon:

      [Plantinga's argument is not "obviously true". It is obviously stupid.]

      But your logical mental apparatus evolved to mate, not to sift arguments on blogs.

      Are you hitting on me, big boy?

      Delete
    2. But your logical mental apparatus evolved to mate, not to sift arguments on blogs.

      It evolved to survive. But since you don't understand evolution to begin with, it isn't surprising that you got that wrong. Or that you fell for Plantinga's hilariously silly argument.

      Delete
    3. Are you hitting on me, big boy?

      Revealing your secret desires now are you?

      Delete
  5. Look around you, Anon has evolved to do a lot more than mate.

    -KW

    ReplyDelete
    Replies
    1. Sorry, KW. Anon is already hitting on me. You'll have to wait your turn.

      Delete
    2. Anon is already hitting on me. You'll have to wait your turn.

      So your secret sexual desires are revealed.

      Delete
    3. Sorry, bigoted ignoramuses are not my type. You'll just have to live with your homoerotic fantasies.

      Delete
    4. Actually, my fantasies are about a tryst with an idiot.

      I'm starting to get tingly...

      Delete
    5. Actually, my fantasies are about a tryst with an idiot.

      Ah, so you are into autoeroticism. Predictable. Do you stare into the mirror?

      Delete
  6. Michael,

    Well, you've made so many many demonstrably untrue statements about evolution, AGW and Rachel Carson, amongst others, so why should we take leave of our senses and trust your interpretation that the waffle Plantinga is not only true but also profound?

    ReplyDelete
    Replies
    1. Michael,

      Do you actually believe that your senses give such an unreliable picture of reality and that your beliefs are true but not adaptive? Really?

      Plantinga is basically saying that our senses are unreliable, which is true but trivial, and that are beliefs are adaptive but not necessarily true, which is correct in some but not all circumstances, and again trivial.

      Our senses are fallible, because our brains have to interpret the imperfect sensations they receive. That's the reason why we have science with its objective measuring devices. The fictional N radiation was discovered by scientists using subjective methods and fooled by their wishes.

      And he's claiming that his subjective senses and wishes are more reliable than his objective senses? He wants to reject science, which is testable, with something which isn't and never be?

      Absolute nonsense.

      Delete
    2. @bach:

      [Do you actually believe that your senses give such an unreliable picture of reality and that your beliefs are true but not adaptive? Really?]

      Plantinga's main interest in philosophy is warrant for belief: what reasons do we have to think that our beliefs are true. For some beliefs (boiling water will burn us) trial and error are sufficient warrant. For other beliefs (God is the Prime Mover, Pi is an irrational number) trial and error are not sufficient. We must use logic and abstract thinking. Even for some beliefs that seem to be confirmable by trial and error may not be absolutely demonstrable by trial and error. Many different beliefs might explain a given outcome.

      Plantinga argues that our abstract beliefs-- mathematical proofs, theology, abstract reason-- do not seem to have a tight correspondence to reproductive success. If anything, distraction by such things may reduce our fecundity. The football star, not the philosophy nerd, gets the girls, and the offspring.

      Thus, our beliefs, if they are evolved, evolve to increase fecundity, not to increase ability to discern abstract truths. It may be that in some instances there is a correspondence between fecundity-increasing beliefs and abstract-truth-discerning beliefs, but that is not a necessary correspondence, and can easily be a negative correlation.

      Therefore, evolved beliefs are not a reliable guide to abstract truth. They are a reliable guide to optimizing fecundity.

      [Plantinga is basically saying that our senses are unreliable, which is true but trivial, and that are beliefs are adaptive but not necessarily true, which is correct in some but not all circumstances, and again trivial.]

      His point is not trivial at all. Beliefs that are true but not adaptive will not be favored by selection, and will tend to disappear.

      [Our senses are fallible, because our brains have to interpret the imperfect sensations they receive. That's the reason why we have science with its objective measuring devices.]

      So what?

      [And he's claiming that his subjective senses and wishes are more reliable than his objective senses? He wants to reject science, which is testable, with something which isn't and never be?]

      We're discussing his evolutionary argument against naturalism. Stay on topic.

      [Absolute nonsense.]

      If your opinion that his views are absolute nonsense does not increase your reproductive success, it is not an evolved opinion.

      If it is not evolved, how did you come to have the opinion?

      Delete
    3. Refute his argument.

      Why would anyone need to? Plantinga refutes his own argument by saying that the probabilities of an event that already occurred are "inscrutable" and then pulling made up probabilities out of his ass. He has already misused probability in his argument and says up front that what he purports to be calculating is unknowable.

      Plantinga's argument is a joke, and he knows it. You are too addle-brained to see it.

      Delete
  7. The idea that science is "Modern theoretical science is wholly a product of Christian civilization, and depends utterly on the Christian understanding of creation and God." is extremely flawed.

    For without the pioneering work of Muhammad ibn-Musa al-Khwarizmi, there would not be Algebra, which forms the foundation of Calculus, and Calculus of course forms the bedrock of modern theoretical science.

    So clearly, your statements about science are outright lies and distortion for personal gain.

    ReplyDelete
    Replies
    1. I shouldn't have to tell you that he was most definitely not a Christian.

      Delete
    2. But definitely not a atheist.

      Delete
    3. "For without the pioneering work of Muhammad ibn-Musa al-Khwarizmi, there would not be Algebra ..."

      This clain is, of course, false. The ancient Greeks developed algebra.

      Delete
  8. @Wa:

    [The idea that science is "Modern theoretical science is wholly a product of Christian civilization, and depends utterly on the Christian understanding of creation and God." is extremely flawed.]

    I am referring to modern theoretical science-- physics, chemistry, biology, etc.

    Other sciences-- math, logic, engineering etc have arisen in many cultures.

    But is simple historical fact that modern science as we understand it is wholly a Christian achievement.

    The fact that you name one individual-- in math, not science-- makes my point, not yours.

    The Scientific Revolution that began in the 16th century is a Christian revolution. In recent times, scientist from other cultures have of course contributed, but they are almost always trained in historically Christian universities and systems.

    Islamic science, pagan science, etc have been astonishingly sterile. Deal with it.

    [So clearly, your statements about science are outright lies and distortion for personal gain.]

    Describe the modern scientific contributions-- not engineering, not math, but modern theoretical science-- that has come entirely from non-Christian cultures.

    Until you can, it's not me who is lying and distorting.

    And what, pray tell, would be my "personal gain" in tutoring you on the history of science?

    ReplyDelete
  9. Apparently Japan China and all atheists contribute "Nothing" to science. What a ludicrous point of view. So if there are atheists and Christians working in the same lab only the Christians know anything? Christians waste valuable time reading the same text over and over again and going to church. Atheists can spend more time researching. Anyway Christians, for being so allegedly bright, have failed to tell us which Christian religion is the right one.

    Please go away and let us get on with some work. When you have figure out the answer to this problem get back to. Even the two Republicans candidates cannot agree on which cult is the right one.

    ReplyDelete
    Replies
    1. I'm not saying that individual scientists from other cultures didn't contribute to modern science. Of course they did.

      I said that modern science arose from Christian culture. That is a matter of simple fact. There were of course some scientists who came from other cultures who contributed, but they did so in a Christian milieu.

      If I'm wrong, tell me about all of the great contributions to modern theoretical science (not engineering or mathematics, which have multicultural origins) by Islamic, atheist, or pagan cultures.

      The Scientific Revolution was a Christian revolution. If I'm wrong, provide me with evidence to the contrary. Specifics.

      Delete
  10. The only rationale for apologetics existing is to provide arguments for believers to believe. They need not be good arguments, and indeed, actually they're very bad ones, as this video shows. If the arguments were good, there wouldn't be so many many atheists around. Not only that, if the arguments were good, they'd even convince those who are inclined to believe to convert to Christianity..

    Science is testable. Reality is testable. Plantinga's subjective feeling that there's a god is not testable. Not now. Not ever.

    ReplyDelete
    Replies
    1. @bach:

      Plantinga's discussion of the reliability of intuition of course is not the same thing as his evolutionary argument against naturalism.

      I point out that intuition plays a much greater role in our lives than does the scientific method. Our most important personal relationships, our deepest beliefs, our habits, our likes and dislikes, our self-image are all based almost entirely on intuition.

      Richard Dawkins loves his wife and daughter deeply, I'm sure, and he's never done any scientific experiments to prove it.

      Plantinga is right. We are right to give our intuition credit for affirming very important things. No one in their right mind-- especially not atheists-- subjects the most important things in life to the scientific method.

      Delete
    2. M.Egnor: "I point out that intuition plays a much greater role in our lives than does the scientific method. Our most important personal relationships, our deepest beliefs, our habits, our likes and dislikes, our self-image are all based almost entirely on intuition."

      Actually, it goes even deeper than that.

      ALL our knowledge, including all rational knowledge we, whether individually or corporately, have acquired (of which any 'scientific knowledge' which happens actually to be true is but a subset) is based entirely on intuitive knowledge. For example, that [1+1=2] ant that [1+1!=n (where n!=2)] are not know via reason but via intuition -- we know these statements are true because we know they are true -- and then, on the basis of knowing those truths intuitively, we can know, rationally, that [2+2=4] and that [2+2!=n (where n!=4)]

      Delete
    3. Michael,

      What is intuition? If you don't know what it is, then you can't claim that it's a better method for making choices.

      Delete
    4. You know what intuition is.

      Nearly all your choices and beliefs are guided by it. You subject very little in your life to detailed scientific analysis.

      In fact, the most important things in your life are those which are guided by intuition-- love, trust, happiness.

      Delete
    5. Science is not testable. Falsification is required. Try to improve your school knowledge, please!

      Delete
  11. "Science is testable. Reality is testable."
    Your testimony/assertion of faith in a specific method of inquiry above all others is uncharacteristically honest, Bach - but the assertion adds nothing to the conversation.

    ReplyDelete
  12. Fiend for Intellectual Dishonesty: "Science is testable. Reality is testable. Plantinga's subjective feeling that there's a god is not testable. Not now. Not ever."

    Hmmmm.

    So, Darwinism isn't 'science', then? Well, I always did expect as much.

    Then, there is 'xenobiology', a "science" without a subject matter to even observe, yet plenty of "experts" doing the non-observation.

    Oh! Let us not forget "string theory" or "M theory" or whatever they call it these days.

    And the so-called "multiverse" -- of which, by definition, not even in principle, can any tests ever be conducted.

    And who can forget this bit of "science"? -- "Consider this claim: as I walk along, time -as measured by my wristwatch or my ageing process -slows down. Also, I shrink in the direction of motion. Also, I get more massive. Who has ever witnessed such a thing? It's easy to dismiss it out of hand. Here's another: matter and antimatter are all the time, throughout the universe, being created from nothing. Here's a third: once in a very great while, your car will spontaneously ooze through the brick wall of your garage and be found the next morning on the street. They're all absurd! But the first is a statement of special relativity, and the other two are consequences of quantum mechanics (vacuum fluctuations and barrier tunnelling,* they're called). Like it or not, that's the way the world is. If you insist it's ridiculous, you'll be forever closed to some of the major findings on the rules that govern the Universe.

    *The average waiting time per stochastic ooze is much longer than the age of the Universe since the Big Bang. But, however improbable, in principle it might happen tomorrow.
    " --- Reader, don't you think it odd that these "skeptics" will affirm the assertion that "once in a very great while, your car will spontaneously ooze through the brick wall of your garage and be found the next morning on the street", because someone asserted that assertion is 'Science!, that they will affirm this assertion even though no one has ever claimed to have observed it, even though by its very nature it isn't testable, YET these same "skeptics" will adamantly deny that anyone has ever observed an iron axehead float to the top of the water in which it had been lost, even though someone did claim to have witnessed exactly that?

    Fiend for Intellectual Dishonesty: "Science is testable. Reality is testable. Plantinga's subjective feeling that there's a god is not testable. Not now. Not ever."

    These people are intellectually dishonest -- their "skepticism" is highly selective, their self-toutes committment to "reason" is a sham. Plantinga does not "argue" on the basis of subjective feelings (but these fools and liasr will and do), he argues and reasons on the basis of the most rationally trustworthy tool we have, sound logic.

    These people are intellectually dishonest -- they are worse than liars; for liars merely lie about some fact or other, but these people lie about the very nature of truth and of reason and logic.

    ReplyDelete
    Replies
    1. So, Darwinism isn't 'science', then?

      Since you clearly don't understand the theory of evolution by natural selection, or any of the other fields of science that you mention, you probably should go back and take some remedial classes before you make a fool out of yourself some more.

      Plantinga does not "argue" on the basis of subjective feelings

      Of course he does. His "probabilities" are entirely made up. Plantinga's "logic" is wishful thinking because he invents from whole cloth every thing that he starts with.

      Delete
  13. Fiend for Intellectual Dishonesty: "Science is testable. Reality is testable. Plantinga's subjective feeling that there's a god is not testable. Not now. Not ever."

    Here is a bit of reality that is testable -- these people are not only intellectually dishonest, but they are also irrational: they will *always* retreat into irrationality, they will always deny that we can even reason and discover, much less know, truth when the truth discovered by reason is "God is". They make this retreat for two reasons:
    1) it they did not make the retreat, they would be admitting that "God is" is true;
    2) the denial that we can even reason and know truth, in the first place, is actually a logical entailment of the denial that "God is"

    ========
    Until an 'atheist' admits that "God is", he really doesn't have a place in the conversation which is the topic of the OP. Until an 'atheist' admits that "God is", he's just a "troll" -- and we who wish to better understand the topic of the OP should not be feeding the trolls.

    ReplyDelete
    Replies
    1. Until an 'atheist' admits that "God is", he really doesn't have a place in the conversation

      As long as you believe fairy tales, there's no reason to take you seriously on any subject. Keep pretending, but your drivel is empty and hollow, and the fact that it is being exposed as such frightens you to your core.

      Delete