Introduction

Alvin Plantinga’s Evolutionary Argument Against Naturalism (EAAN) has proven to be a resilient obstacle for the naturalist. In this essay, we put forth a novel solution to Plantinga’s argument, utilizing Duncan ’s recent work on radical skepticism (2016). Specifically, we argue that if subject S’s commitment to the reliability of her cognitive faculties (the doubting of which is central to Plantinga’s argument) is best understood as an arational hinge commitment rather than a belief, Plantinga’s argument cannot get off the ground. In order to establish this thesis, first, in Sect. 2, we lay out Plantinga’s argument. In Sect. 3, we examine a closure-based radical skeptical paradox, and show how the EAAN is structurally similar. In Sect. 4, we lay out Pritchard’s hinge epistemological solution to closure-based radical skepticism and, in Sect. 5, apply it as a solution to the EAAN. Of course, our response will only work if one is already open to hinge epistemology. But assuming that this is the case, we think the solution we put forward is a plausible one.Footnote 1, Footnote 2

The evolutionary argument against naturalism

Plantinga’s (in)famous EAAN attempts to cast doubt on the reliability of one’s cognitive faculties (R) by way of developing an undercutting defeater that results from believing that both naturalism and evolution (N&E) are true. Plantinga lays out the EAAN as follows:

  1. 1.

    P(R/N&E) is low.

  2. 2.

    Anyone who accepts N&E and sees that P(R/N&E) is low has a defeater for R.

  3. 3.

    Anyone who has a defeater for R has a defeater for any other belief she thinks she has, including N&E itself.

  4. 4.

    If one who accepts N&E thereby acquires a defeater for N&E, N&E is self-defeating and can’t be rationally accepted.

    Conclusion: N&E can’t rationally be accepted. (Plantinga, 2011: 344–345)

The argument is wholly motivated on (1). While technically you can develop the defeater by just mentioning (2)–(4), the idea is that the argument won’t be worth taking seriously unless (1) can be established. That is, there needs to be some reason as to why the naturalist should think R is low given N&E. So, why think (1) is true? Evolution, on naturalism, is driven by natural selection—a process that, as Patricia Churchland explains, “enables the organism to succeed in the four Fs’: feeding, fleeing, fighting, and reproducing. The principle chore of the nervous system is to get the body parts where they should be in order to survive.” (Churchland, 1987: 548–549) Yet, as Churchland points out, natural selection is seemingly indifferent as it relates to the production of true beliefs. If the formation of our cognitive faculties is determined by adaptiveness and not accurate belief content, why think the evolutionary process has produced reliable cognitive faculties that possess the capability of tracking truth? In fact, why think there is even a connection between the content of one’s belief and the actions selected for by evolution? One of the dilemma’s the EAAN imposes upon the naturalist is that seemingly any attempt to justify the use of one’s cognitive faculties on N&E will require the use of one’s cognitive faculties (which assumes they are reliable), which is circular.

Now, one might respond to Plantinga by first conceding that the propositional evidence by itself is such that R is low, however, the responder might advocate that one could appeal to non-propositional evidence that makes it such that when taking both the propositional and non-propositional evidence together, R would not be low (Bergman, 2002: 68–69.) As some have argued however, this move only seems plausible given certain externalist commitments (See, Baldwin & McNabb, 2019.). For the sake of argument, let’s assume that Plantinga’s EAAN is successfulFootnote 3—where, epistemically, does the naturalist find herself? Seemingly, the epistemic position of one holding to belief in N&E&EAAN is one of Cartesian radical skepticism. To draw this point out, let us first turn to a more general argument for radical skepticism to juxtapose with Plantinga’s argument.

Radical skepticism & EAAN

Take the following closure-based radical skeptical paradox as formulated by Pritchard (where BIV = Brain-in-a-vat and E = everyday propositional knowledge):

  1. 1.

    One cannot have rationally grounded knowledge that one is not a BIV.

  2. 2.

    If one cannot have rationally grounded knowledge that one is not a BIV, then one cannot have rationally grounded knowledge that E.

  3. 3.

    One has rationally grounded knowledge that E. (Pritchard, 2016: 22.)

In the above formulation we have two generally accepted epistemic claims, namely (1) & (3), with (2) being the bridging claim, which creates the paradox. The bridging claim is a version of the closure principle, which states, “If S has rationally grounded knowledge that p, and S knows that p entails q, then S has rational grounded knowledge that q.” (Ibid. 22.) As it relates to radical skepticism, if we have rationally grounded knowledge of E, and having rationally grounded knowledge of E entails that we have rationally grounded knowledge that we are not a BIV, then we should have rationally grounded knowledge that we are not a BIV. But as we see in (1), according to Pritchard, we do not have rationally grounded knowledge that we are not a BIV. Therefore, via the closure principle, we cannot have rationally grounded knowledge of E.

EAAN as radical skepticism

Could we reformulate the above brain-in-a-vat radical skeptical scenario, replacing BIV with premise 1 from the EAAN, and arrive at the same place (namely, in a place of radical skepticism regarding E)? Take the following paradox:

  1. 1.

    One cannot have rationally grounded knowledge if one concludes that R is low.

  2. 2.

    If one cannot have rationally grounded knowledge if one concludes that R is low, then one cannot have rationally grounded knowledge that E.

  3. 3.

    One concludes that P(R|N&E) is low (via EAAN)

  4. 4.

    One has rationally grounded knowledge that E.Footnote 4

One could object that this latter scenario is sound only if premise one of Plantinga’s original argument [P(R|N&E) is low] is equivalent to BIV (specifically, as it relates to one’s resulting epistemic position). We believe it is. Specifically, if we are to grant that P(R|N&E) is low, then it does seem to follow that all of our everyday propositional knowledge could be fundamentally mistaken in the same way that we could be fundamentally mistaken in the BIV scenario. Again, on Plantinga’s EAAN, the evolutionary process gives us no reason to believe that any of our cognitive abilities are reliable: the reliability of our perceptual abilities, mnemonic abilities, sensory abilities, reasoning abilities, and the like are all brought into question in a similar way to the way these abilities are brought into question if we cannot show that we are not a brain-in-a-vat. As Plantinga, in a similar vein to Churchland, explains:

What evolution underwrites is only (at most) that our behavior is reasonably adaptive to the circumstances in which our ancestors found themselves; hence it does not guarantee mostly true or verisimilitudinous beliefs. Our beliefs might be mostly true or verisimilitudinous…but there is no particular reason to think they would be: natural selection isn’t interested in truth, but in appropriate behavior. (Plantinga, 2011: 316.)

Obviously, the process by which we arrive at radical skepticism differs (in the BIV scenario we are being deceived by a mad-scientist or an Evil Demon or ET). However, the crucial similarity is that, in both cases we cannot show that our faculties are reliable, and, as a result, lack justification of our everyday propositional knowledge (a claim one generally takes as axiomatic).

Given the structural similarities between closure-based radical skepticism and the EAAN (as construed in Sect. 3.1), a solution to the former should also serve equally well as a solution to the latter. We now turn to provide such a solution, first analyzing Pritchard’s solution to closure based radical skepticism and then applying it to the EAAN.Footnote 5

Hinge commitments

As it relates to closure-based radical skeptical paradox, Pritchard argues that it is not the generally accepted epistemic principles, nor the closure principle, that are problematic, rather, it is an underlying entailment embedded in the paradox that is to be rejected: namely, the universality of rational evaluation. According to this thesis, there are no in-principle constraints on the scope of rational evaluation; the move from local (E) to global (BIV) rational evaluation is permissible.

In order to resolve the paradox, Pritchard simply denies the universality of rational evaluation. The problem with this thesis, according to Pritchard, is that the move from local to global rational evaluation is incoherent. Following Wittgenstein, Pritchard argues that the structure of rational evaluation is groundless: all rational evaluation follows relative to arational, visceral, propositional attitudes termed hinge commitments, which are “never the result of a rational process and are in their nature unresponsive to rational considerations, they are not plausible candidates to be beliefs.”Footnote 6 (Pritchard, 2016: 90.)

Examples of hinge commitments are the famous Moorean certainty “I have two hands” or “I’m not on the moon” or “I’m writing this essay in English.” These optimally certain claims cannot be rationally doubted because, the reasons for doubting them are going to be less certain than the claims in question. On the other hand, these commonsense claims can neither receive rational support because, once again, the claims used to support them will be less certain than the claims themselves. The primary idea being, rationally grounded knowledge requires support from claims that are more certain than the claims in question. In contrast, to doubt claims considered to be rationally ground knowledge would also require an appeal to claims that are more certain than the claims in question. Either endeavor is, by definition, impossible when considering claims that are optimally certain.

Thus, “the very idea of rational evaluation, whether positive or negative, presupposes a backdrop of Moorean certainties that are themselves exempt from rational evaluation. To attempt to rationally evaluate a Moorean certainty is thus an attempt to do something impossible…[or] incoherent.” (Pritchard: 65–66) Wittgenstein uses the analogy of the hinges of a door to highlight this idea. In order for a door to open the hinges must stay in place. (Wittgenstein, 1969) 

While it is clearly possible for hinge commitments to change (it is possible, say, that some future human civilization may inhabit the moon), they “all in effect codify…the entirely general hinge commitment that one is not radically and fundamentally mistaken in one’s beliefs.” (Pritchard, 2016, 95) This idea is known as the über hinge commitment: one’s hinge commitments can change to beliefs, however, the underlying general commitment, regardless of context, is that one is not radically deceived. This über hinge then, helps form and stabilizes the hinge commitment in question.

As such, again it is worth repeating, hinge commitments (the über hinge commitment included) are exempt from rational evaluation. Hinge commitments, according to Pritchard, are “never the result of a rational process and are in their nature unresponsive to rational considerations, they are not plausible candidates for beliefs.”Footnote 7 (Ibid: 90) Pritchard summarizes his arguments as follows:

Since all rational evaluation presupposes arational hinge commitments that are by their nature exempt from rational evaluation, this puts an in-principle constraint on the extent of rational evaluations. In particular, it excludes the kind of wholesale rational evaluations that call into question our hinge commitments, and that are the stock in trade of the radical skeptic. (Ibid: 175)

With the use of hinge commitments, Pritchard is able to limit the scope of rational evaluation to local and, in turn, deny the universality of rational evaluation. By denying this entailment, Pritchard has a response for the closure-based radical skeptical paradox.

We take the following as necessary conditions for a proposition to be considered a hinge commitment:

  1. 1.

    The proposition in question is more certain than any claim that can be appealed to for support of the proposition (positive rational evaluation).

  2. 2.

    The proposition in question is more certain than any claim that can be appealed to in order to doubt the proposition (negative rational evaluation).

  3. 3.

    The Uber Hinge: To doubt the proposition in question would result in radical skepticism.

We now turn to show how Pritchard’s hinge epistemology serves equally well as a solution to Plantinga’s EAAN.

EAAN resolved: (R) as Hinge

Given that P(R|N&E) results in a paradox structurally similar to closure-based radical skepticism, Pritchard’s hinge solution provides a natural remedy. Specifically, our commitment to R, the reliability of our cognitive faculties, is a hinge commitment, immune from rational evaluation. According to hinge epistemologists, R cannot face positive or negative rational evaluation due to the fact that one would need to assume the reliability of their cognitive faculties in order to evaluate the reliability of their cognitive facilities. Thus, if anything is to be exempt from rational evaluation (positive or negative), it’s R.

Lastly, the litmus test for a hinge commitment is the über hinge. Specifically, if one doubts R, does one’s epistemic position collapse into radical skepticism? As shown in the EAAN version of the paradox above, this does seem to be the result of doubting the reliability of one’s cognitively faculties. However, according to the über hinge, we aren’t radically deceived (in turn, R’s being undoubtable). Thus, with no possible positive or negative rational evaluation available, in addition to satisfying the über hinge, R seems to be a prime candidate for a hinge commitment. In other words, to doubt R is a case of global rational evaluation. As a result, the naturalist who is a proponent of Pritchard’s hinge epistemology can simply deny premise 1 of the EAAN, and, in turn, deny the soundness of the argument.

Conclusion

Pritchard (2015, 2018) has elsewhere argued that Wittgenstein’s thinking regarding the structure of rational evaluation was motivated by the work of Newman (2016). Whether or not Newman would have endorsed Wittgensteinian epistemology full-stop is up for debate, however, one passage from his famous An Essay in Aid of A Grammar of Assent, clearly suggests that Newman did take one aspect of the human experience to be unquestionable: the reliability of our cognitive faculties. Newman writes:

It seems to me unphilosophical to speak of trusting ourselves. We are what we are, and we use, not trust our faculties. To debate about trusting in a case like this, is parallel to the confusion implied in wishing I had had a choice if I would be created or not, or speculating what I should be like, if I were born of other parents…We are as little able to accept or reject our mental constitution, as our being. We have not the option. (Newman, 55)

Here, Newman is rejecting the idea that the reliability of our cognitive faculties is a foundational, or basic ‘first principle’, but rather, is arguing that R is simply a commitment “swallowed down” in order to engage in any rational evaluation, and to doubt such a commitment is, as Newman states, “unphilosophical.” If the reader finds Newman’s words here compelling, we think the reader will have motivation to accept the proposal of this paper.Footnote 8