In the latest Phil Perspectives, “Roger White”:http://philosophy.fas.nyu.edu/object/rogerwhite has a paper “Epistemic Permissiveness”:http://philosophy.fas.nyu.edu/docs/IO/1180/EP.pdf argues against what he calls epistemic permissiveness, the view that in some evidential states there are multiple doxastic attitudes that are epistemically justified and rational. I call this epistemic liberalism, because at least in America liberal is a nice word. (‘In America’ of course functions something a negation operator.) I think there are a few things we liberals can say back to Roger’s interesting arguments. In particular I think a liberalism that allows that there are epistemically better and worse responses among the rational responses, just like we think that among the morally permissible actions some are morally better and worse, has some resources to deploy against his challenges. But for now I want to take a different tack and defend liberalism directly.

Some days I’m inclined to think that liberalism, like anti-scepticism, is so obviously plausible from casual observation of the world that the challenge is to find what is wrong with any anti-liberal argument. But unlike anti-scepticism, I think we can argue for liberalism as follows. The argument assumes that Timothy Williamson’s anti-luminosity view is broadly correct. Although I’ve argued that Williamson doesn’t rule out all possible luminous sources, I think he’s right that there is much less that is luminous than we previously thought.

Consider a series of agents, e₀, …, e_n, such that e₀ has evidence we would normally regard as compelling evidence that ~p, but each e_i has ever so slightly more evidence that points in favour of p, so that taken as a whole e_n has compelling evidence that p, and even we liberals think that her only permissible state is to believe that p.

Now assume, for reductio, that liberalism is false, so for each e_i they either must believe that ~p, must suspend judgment as to whether p, or must believe that p. Since as i increases e_i has strictly more evidence that p, in the sequence there is a first person who must suspend judgment that p, and a first person who must believe that p. Consider that person, call her e_j. (By the way, I’m not assuming epistemicism about vagueness here; if supervaluationism is true everything I’ve said is supertrue.)

Now e_j must, if she is rational, believe that p. But by standard safety considerations, she cannot know this. The reason is that her evidence is practically indistinguishable from the evidence that e_j-1 has, and e_j-1 cannot rationally believe that p. If e_j believes that she must believe that p, her belief will be unsafe and hence not knowledge. Assuming knowledge is the norm of belief, at least when it comes to propositions about epistemic justification, it follows that e_j must rationally suspend judgment about whether she must (indeed may) believe that p.

This last step has to be taken carefully. Why say that it follows from e_j not knowing something that she can’t rationally believe it? I think for the following reason. It’s a platitude that belief aims at knowledge. The best thing to do is to know. And, quite plausibly, it is better to suspend judgment than to believe without knowing. Now anti-liberalism says that only the best will do. Anything else is irrational, by the definition of anti-liberalism. So the anti-liberal says that it is only rationally permissible to believe what you know. Perhaps we can imagine some variations on this in cases of deception (if it mistakenly seems that p, perhaps it is better to believe p than suspend judgment) but this is not a case of deception; e_j does not get any misleading evidence at all about the support her evidence offers for p. In these cases at least (and perhaps in all cases) the best thing to do is to believe iff you know.

So rationality demands of poor e_j that she believe that p, and suspend judgment about whether it is rationally permissible in her situation to believe that p.

This seems to me like a very bad result. Indeed, it is not at all clear that it could be rational to have those attitudes. It seems to me that the rational agent should believe that their beliefs are rationally permissible. But the anti-liberal says that e_j must not believe this if she is to be rational. That seems like a reductio of anti-liberalism to me.

Note this is a result that the liberal avoids. The liberal thinks there are more boundaries than the anti-liberal sees.

First, there is the boundary between those who must believe p and those who need not. Let e_k be the first agent on the continuum who must believe that p. If she is rational she believes that p, of course, but since the agents near her all can believe that p, she can know that it is rational to believe that p.

Second, there is the boundary between those who may believe that p and those who may not. Let e_m be the first agent on the continuum who may believe that p. Now she can believe p, but she can’t know that she can believe that p. Is this a problem in itself? Well no, it’s just a consequence of anti-luminosity that such agents exist. What would be a problem would be if she could rationally believe p, but couldn’t believe such a belief is rational. But if liberalism is true this isn’t the position e_m is in. Perhaps in her case the best thing for her to think about the rational permissibility of believing p is to suspend judgment. (At least that’s the best thing ceteris paribus; since she believes p perhaps ceteris isn’t paribus here. I’m not sure how to resolve this issue.) But the liberal also thinks that sometimes doing less than the best can be rational, just like doing less than the best can be moral. So it’s consistent with liberalism that e_m can rationally believe that it is rational to believe that p.

These borderline cases are hard. But the liberal can say things about them that sound coherent, and even plausible. The anti-liberal is forced to say it is rationally mandatory to have a belief and suspend judgment about the rationality of your own belief. That seems like an implausible, even incoherent, description. So these cases offer strong support for liberalism.