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The Evolutionary argument against naturalism (sometimes abbreviated EAAN) is a philosophical argument that metaphysical naturalism when combined with contemporary evolutionary accounts of the origin of human life is in a certain interesting way self-defeating[1]. Although C. S. Lewis made somewhat similar observations, the argument as it is commonly presented was first put forward and has mostly been developed by Alvin Plantinga, a contemporary philosopher of epistemology at the University of Notre Dame.
C. S. Lewis
The general claim that naturalism undercuts its own justification was argued by C. S. Lewis in the third chapter of his book Miracles, as well as in numerous other writings. For instance, in "On Living in an Atomic Age" he claimed that “It is only through trusting our own minds that we have come to know Nature herself. If Nature, when fully known, seems to teach us (that is, if the sciences teach us) that our own minds are chance arrangements of atoms, then the sciences themselves would be chance arrangements of atoms and we should have no reason for believing them.”
[edit] Plantinga's Argument
Alvin Plantinga's argument attempts to show that combining naturalism and evolution is self-defeating because under these assumptions the probability that humans have reliable cognitive faculties is low or inscrutable.[2] The argument has been published by the Oxford University Press in Warrant and Proper Function, and a presentation of the argument can be found on the web[1]. A more recent and extensive discussion is found in Naturalism Defeated? Cornell (2002), in which Plantinga sets out the argument, 11 philosophers comment and Plantinga responds.
Plantinga makes it clear that he is not attacking the theory of evolution[3], and introduces his argument with a quotation by Charles Darwin:
Charles Darwin in 1880.
With me, the horrid doubt always arises whether the convictions of man's mind, which has been developed from the mind of the lower animals, are of any value or at all trustworthy. Would anyone trust in the convictions of a monkey's mind...?
– Charles Darwin.[4]Plantinga defines:
and suggests that P(R/N&E) is low.
- N as naturalism
- E as the belief that we human beings have evolved in conformity with current evolutionary doctrine
- R as the proposition that our faculties are "reliable", where, roughly, a cognitive faculty is "reliable" if the great bulk of its deliverances are true. He specifically cites a thermometer stuck at 72 degrees placed in an environment which happened to be at 72 degrees as an example of something that is not "reliable" in this sense[5]
Plantinga's argument begins with the observation that our beliefs can only have evolutionary consequences if they affect behaviour. To put this another way, natural selection does not directly select for true beliefs, but rather for advantageous behaviours. Plantinga distinguishes the various theories of mind-body interaction into four jointly exhaustive categories:
- epiphenomenalism, where behaviour is not caused by beliefs. "if this way of thinking is right, beliefs would be invisible to evolution" so the P(R/N&E) would be low or inscrutable[6]
- Semantic epiphenomenalism, where beliefs has a causative link to behaviour but not by virtue of their semantic content. Under this theory, a belief would be some form of long-term neuronal event[7]. However on this view P(R/N&E) would be low because the semantic content of beliefs would be invisible to natural selection, and it is semantic content that determines truth-value.
- Beliefs are causally efficacious with respect to behaviour, but maladaptive, in which case he suggests P(R/N&E) would be low because R would be adversely selected for.
- Beliefs are causally efficacious with respect to behaviour, and adaptive. Since behaviour is caused by both belief and desire and desire can lead to false belief, there are many ways in which beliefs could be false but adaptive and natural selection would have no reason for selecting true but non-adaptive beliefs over false but adaptive beliefs. Thus he suggests that P(R/N&E) in this case is also low.[8] Plantinga points out that innumerable belief-desire pairs could account for a given behaviour; for example, that of a prehistoric man fleeing a tiger:
Perhaps Paul very much likes the idea of being eaten, but when he sees a tiger, always runs off looking for a better prospect, because he thinks it unlikely the tiger he sees will eat him. This will get his body parts in the right place so far as survival is concerned, without involving much by way of true belief... Or perhaps he thinks the tiger is a large, friendly, cuddly pussycat and wants to pet it; but he also believes that the best way to pet it is to run away from it... Clearly there are any number of belief-cum-desire systems that equally fit a given bit of behaviour.[9]Thus, Plantinga argues, the probability that our minds are reliable under a conjunction of philosophical naturalism and evolution is low or inscrutable, and therefore asserting that naturalistic evolution is true also asserts that one has a low probability of being right. This, Plantinga argues, epistemically defeats the belief that naturalistic evolution is true and that ascribing truth to naturalism and evolution is internally dubious or inconsistent.
Plantinga contrasts the purely naturalistic-evolutionary view with the alternative theistic view that, while accepting the scientific description of evolutionary processes, also allows for the presence of a God who is capable of creating a universe, the physical properties of which produce reliable human cognitive faculties, even though the direct physical cause thereof is undirected (see, for example, the philosophical position known as theistic evolution)...
http://en.wikipedia.org/wiki/Evolutionary_argument_against_naturalism
I have a friend who is earning his PhD under Alvin Plantinga. This professor seems like a pretty sharp guy.
Naturalism Defeated by Alvin Plantinga
http://www.calvin.edu/academic/phil...icles/plantinga_alvin/naturalism_defeated.pdf
Peace.
