1. In what conditions ought one to believe something? For example, ought one to believe that human-caused climate change is occurring? It’s sometimes suggested that the following answer should be accepted:
(Ought-1) One ought to believe P if and only if P.
(Ought-RL) If P, then one ought to believe P.
(Ought-LR) If not-P, then one ought not to believe P.
(1) If human-caused climate change is occurring, then one ought to believe that human caused climate change is occurring.
(2) If it’s not the case that human-caused climate change is occurring, then one ought not to believe that human caused climate change is occurring.
However, Ought-RL looks to be incorrect. For it claims that one ought to believe every truth. There are two central problems here.
The first problem rests on a very plausible—though controversial—claim, to the effect that ought implies can. According to the ought-implies-can claim, if one ought to A, then one can A. For instance, if one ought to make others happy, then one can make others happy. Crucially, it seems to follow that if one can’t A—if one can’t make others happy—then it isn’t the case that one ought to A—it isn’t the case that one ought to make others happy. Now it’s plausible that there are truths that are too long and complicated for any human to believe—say truths involving the conjunction of all currently known mathematical truths, or the conjunction of all the truths in all the books in the University of Warwick library. If it’s impossible for any human to believe such a truth, then the ought-implies-can claim delivers the result that no human ought to believe such a truth. It would follow that Ought-RL is false.
The second problem is less decisive, but more interesting. In order to avoid impossibility, suppose that someone set themselves the aim of getting as close as they could to knowing the conjunction of all the currently known mathematical truths, or all such truths contained in books within the University of Warwick library. The person in question has no ulterior motive for doing this, no further end for which this is a means. They are pursuing the end entirely for its own sake. They pursue the end for a month or so, and get themselves into a position in which they believe the conjunction of a large number of mathematical truths. Let’s call the conjunctive claim that they come to believe “Q”. We now have that it’s possible to believe Q, so the ought-implies-can claim fails to rule against this being something one ought to do. Nonetheless, it’s hard to believe that, all else being equal, one ought to do what one can to emulate this strange figure. We may admire their resolve, but in other respects it’s hard even to find intelligible the end that they have set themselves, given that it serves no further purposes. To that extent, it seems implausible to claim that, even where P is restricted to truths that it’s possible for one to believe, one ought to believe P just because it’s true.
2. Suppose that’s right. That is, suppose that it’s false that, for every P, regardless of its intrinsic interest or capacity to sub-serve one’s further ends, if P, then one ought to believe P. Now consider the following claim:
(Transparency) “the deliberative question whether to believe that P inevitably gives way to factual question whether P, because the answer to the latter question will determine the answer to the former question” (Shah and Vellemean 2005: 499, with inessential reformulation)
It’s somewhat plausible that one can’t answer the latter question—whether P—without coming to believe either P or not-P. In particular, if one comes up with the answer P, there’s some plausibility in the claim that that would be a way of coming to believe P. Suppose it so. Still, without more ado, coming to believe P doesn’t seem to decide the question whether to believe P. Similarly, if, in the course of deliberating whether to run down a hill, I stumble and begin so running, that isn’t a way of deciding to run down the hill. And in the latter case, it would seem that I might even decide, in the course of flailing wildly down the hill, not to do so, and so make every effort to stop. So, similarly, having come to believe P, I might keep open my deliberation over whether to do so, whether, that is, to continue to believe P. Now in fact, ceasing to believe P is, if anything, less within our control than is ceasing to run down a hill. And that is especially so in conditions where one has no reason to believe P is false. But it’s far from clear that, in either the case of activity or of attitude, the fact that one is saddled decides the deliberative question whether to acquiesce.
Consider, then, the following science fiction case. Suppose that, in 2035, neuroscientists have found a way to extinguish individual beliefs by the use of specially designed radioactive pills hooked up to some future analogue of a mobile phone app. Ishmael, pills dropped and phone in hand, is on a research mission at the University of Warwick library. He is on the hunt for a specific mathematical theorem that he knows is to be found in one of the maths books in the library. He doesn’t know the name of the theorem, but knows enough about it that he will be able to recognise it on presentation with a little reflection. Starting with the “A”s, Ishmael begins reading through books of mathematical theorems. Ishmael accepts as true each of the theorems that he comes across, but has no immediate interest in any of the theorems other than the one he seeks, and no interest that would be served by believing any of those other theorems. With respect to one of these theorems—let’s call it R—Ishmael deliberates over the question whether to believe R. Since he’s answered the factual question whether R, he’s come to believe R. The question driving Ishmael’s deliberation is whether to continue to believe R, given that he has the resources to cease so believing via a couple of key presses. Given that the mere fact that a claim is true does not suffice to make it so that one ought to believe P, it seems that the mere fact that R is true does not suffice to make it so that Ishmael ought to believe it. In particular, its truth does not suffice to make it so that Ishmael ought to continue to believe it. Thus, I think there is some reason to think that Transparency is false.
Dodd, J. (2013). ‘Jane Heal’s “Disinterested Search for Truth”.’ in G. Longworth ed. Proceedings of the Aristotelian Society, Virtual Issue 1, Truth: 138–144.
Heal, J. (1988). ‘The Disinterested Search for Truth.’ Proceedings of the Aristotelian Society, Volume LXXXVIII. Reprinted in G. Longworth ed. Proceedings of the Aristotelian Society, Virtual Issue 1, Truth: 125–136.
Shah, N. and Velleman, D. (2005). ‘Doxastic Deliberation.’ Philosophical Review 114: 497–534.