Can one believe a proposition at will? Can one, for instance, decide to believe a proposition while at the same time recognizing that one’s evidence for it is wanting? The question, note, is not whether there ought to be a role for the will in forming beliefs, but whether there could be such a role. Epistemologists who believe that this question should be answered in the negative typically do so on factual grounds. More specifically, their reasons mostly come down to the contention that, as a matter of contingent fact, belief formation is not sufficiently under our control for it to be a matter of the will. Jonathan Adler sides with these epistemologists as regards the claim that what we believe is not up to us. In contrast to them, however, he thinks this is a conceptual rather than a factual matter. In his view, it can be seen to hold by merely reflecting on the concept of belief that one cannot believe in deviance of one’s evidence (at least not in full awareness; he mentions all sorts of psychological mechanisms that may prevent one from recognizing what one’s evidence is). Or, put positively, in his view it is a conceptual truth that what we believe is a function solely of whatever evidence we happen to have. Belief’s Own Ethics is a book-long defense of this thesis. It is more than that, in fact, for after Adler has argued for the thesis, he meticulously thinks through its consequences for virtually all the ‘big issues’ in epistemology (like, for example, testimony, contextualism, and the lottery and preface paradoxes, to mention but a few). The result is a beautiful book that is exceptionally learned and rich. In the remainder of this review, I confine myself to saying a few words about what is perhaps the book’s most striking feature, to wit its methodology.

In arguing for his thesis, Adler deploys a strategy that one might term Moorean. Moore famously observed that sentences of the schematic form ‘p, but I do not believe that p,’ although not necessarily inconsistent (substituting any true sentence that I happen not to believe in the schema yields a truth), are incoherent: One cannot assert such a sentence without contradicting oneself, whether or not the sentence is true. The explanation Moore offered for this perceived incoherence, and which since has been generally accepted, is that assertion expresses belief, so that in asserting a sentence such as ‘It’s raining in Paris, but I don’t believe that it’s raining in Paris,’ one explicitly denies in the second part of the sentence what one implicitly expresses in the first part. Adler builds his case on sentences that are close to this sort of sentence (he even sometimes just calls them instances of the Moorean schema, which at least strictly speaking is false), namely sentences of the following form,

(+) p, but I lack sufficient evidence for p,

such as, for example, ‘Electrons are negatively charged, but my evidence for the hypothesis that electrons are negatively charged is insufficient.’ Anyone would find such sentences odd-sounding, Adler thinks. In fact, he says, we hear them as contradictions. The explanation he offers for their (alleged) contradictoriness is along Moorean lines: In asserting p one expresses belief in p, and – argues Adler – believing p (at least in full awareness) requires that one regards p as being believed on the ground of sufficient evidence. Thus, in asserting the second conjunct of an instance of (+), one contradicts what one has expressed by asserting the first conjunct of that instance. According to Adler, this shows that the concept of belief simply does not allow one to believe anything in the absence of sufficient evidence for it.

However ingeniously Adler puts this methodology to use in defending his claim that one cannot but believe in accord with one’s evidence, I am not entirely convinced it is the right methodology for his purposes. Grant Adler that our intuitive responses to instances of (+) are as he says they are, that is, that we think they sound odd. Then how telling is that? To be sure, one explanation of the perceived oddness is the one Adler points to, viz., the concept of belief precludes our believing – and thus, via the relation between belief and assertion, our asserting – anything for which we lack sufficient evidence. But it seems that that is not the only possible explanation. Another explanation refers, in first instance, to the fact the we never encounter such sentences – plausibly assuming that odd-soundingness, or the absence thereof, may well be a matter of frequency of exposure – and then goes on to explain this in pragmatic terms, as follows: Typically, when asserting p, I am trying to convince my audience of p. As long as I believe that p is highly likely, I presumably cannot be convicted of trying to deceive the audience by asserting p, even if I fail to be 100% sure of p, that is, even if I recognize that my evidence for p leaves open the possibility that in fact ???p is the case. (Consider that if assertion were non-deceptive only if the person making the assertion had evidence guaranteeing the truth of the assertion, then very few of the assertions we make would count as non-deceptive.) Arguably, I could truthfully describe the epistemic situation I am in by saying: ‘p, but I lack sufficient evidence for p.’ But if I am trying to convince you of p, then rhetorically it surely would be unwise to point to the possibility of error left open by the evidence I have for p. So we tend to suppress such additional clauses as ‘…but my evidence doesn’t rule out the possibility that what I just said is false,’ or, indeed, ‘…but I lack sufficient evidence for what I just asserted.’ Hence we do not normally encounter instances of (+), but not because of anything related to the concept of belief, but because of something related to the purpose of making assertions. The claim is decisively not that the foregoing is the correct explanation of our negative intuitive response to instances of (+). The point of the foregoing is just to show that there is a prima facie not implausible rival explanation to the one Adler proffers. Thus, pending a reason to believe that Adler’s explanation is the better of the two, the methodology he chooses does not quite seem to accomplish what he hopes it accomplishes.

But this worry should not dissuade anyone from reading Adler’s book, for – as I said – it is a beautiful one.