Can Teleosemantics Deflect the EAAN?


Alvin Plantinga’s Evolutionary Argument Against Naturalism aims to show that the conjunction of contemporary evolutionary theory (E) with the claim that there is no God (N) cannot be rationally accepted. Where R is the claim that our cognitive faculties are reliable, the argument is:

  1. P1.

    The probability of R given N and E is low or inscrutable.

  2. P2.

    Anyone who sees (1) and accepts (N&E) has a defeater for R, and this defeater cannot be defeated or deflected.

  3. P3.

    Anyone who has an undefeated, undeflected defeater for R has an undefeated, undeflected defeater for everything she believes.

  4. C.

    Therefore she has an undefeated, undeflected defeater for (N&E).

Plantinga (2011) defends the second premise. It examines and rejects several candidate defeater defeaters and defeater deflectors. One candidate is Millikan’s teleosemantics. I show that Plantinga’s motives for rejecting teleosemantics as a defeater deflector are inadequate. I then show that teleosemantics is not on its own an adequate defeater deflector. Then I offer an additional premise that constitutes a defeater deflector in conjunction with teleosemantics.

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  1. 1.

    By immediate I mean that GnRH acts directly on cells in the pituitary. All biologically useful causal impact of GnRH on ovaries is mediated by the impact of GnRH on the pituitary.

  2. 2.

    We are here forced to reckon with backtracking counterfactuals, as described by Lewis (1979).


  1. Lewis, D. (1979). Counterfactual dependence and time’s arrow. Reprinted in Philosophical Papers, 2, 32–52.

    Google Scholar 

  2. Millikan, R. (1984a). Language, thought, and other biological categories. Cambridge: MIT.

    Google Scholar 

  3. Millikan, R. (1984b). Naturalist reflections on knowledge. Pacific Philosophical Quarterly, 65, 315–334.

    Google Scholar 

  4. Millikan, R. (1995). A bet with Peacocke. In C. MacDonald (Ed.), Philosophy of psychology: Debates on psychological explanation. Cambridge: Blackwell.

    Google Scholar 

  5. Millikan, R. (2000). On clear and confused ideas. New York: Cambridge University Press.

    Google Scholar 

  6. Millikan, R. (2004). Varieties of meaning. Cambridge: MIT.

    Google Scholar 

  7. Millikan, R. (2005). Language: A biological model. Cambridge: Cambridge University Press.

    Google Scholar 

  8. Millikan, R. (2006). Useless content. In G. Macdonald & D. Papineau (Eds.), Teleosemantics. Oxford: Oxford University Press.

    Google Scholar 

  9. Millikan, R. (2012). Reply to Nick Shea. In J. Kingsbury, D. Ryder, & K. Williford (Eds.), Millikan and her critics. Oxford: Blackwell (forthcoming).

    Google Scholar 

  10. Plantinga, A. (1993). Warrant and proper function. Oxford: Oxford University Press.

    Google Scholar 

  11. Plantinga, A. (2002). Introduction: The evolutionary argument against naturalism. In J. Beilby (Ed.), Naturalism defeated? Ithaca: Cornell University Press.

    Google Scholar 

  12. Plantinga, A. (2011). Content and natural selection. Philosophy and Phenomenological Research, 83(2), 435–458.

    Article  Google Scholar 

  13. Shea, N. (2012). Millikan’s isomorphism requirement. In J. Kingsbury, D. Ryder, & K. Williford (Eds.), Millikan and her critics. Oxford: Blackwell (forthcoming).

    Google Scholar 

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Several friends helped in the development of this paper, including Franz Huber, Ruth Millikan,DouglasOwings, and Franklin Scott. An anonymous referee for this journal provided detailed and thoughtful comments and deserves special thanks.

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Correspondence to Brian Leahy.

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Leahy, B. Can Teleosemantics Deflect the EAAN?. Philosophia 41, 221–238 (2013).

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  • Evolutionary Argument Against Naturalism (EAAN)
  • Plantinga
  • Teleosemantics
  • Millikan
  • Productivity