When I first read Timothy Williamson’s Knowledge and Its Limits, one thing that struck me, and stuck with me, was the fact that, while Williamson rejects the KK principle:

KK: If you know that p, then you know that you know that p,

he nonetheless admits the possibility of second-order knowledge, and so accepts what I’ll call P2K:

P2K: It’s possible to know that you know that p.

At the time, the difference between these two principles struck me as somehow important. But simply rejecting KK in favor of P2K didn’t seem quite right. True, KK seems too strong—after all, it it’s true, then knowing something requires not only that you know that you know it, but also that you know that you know that you know it, and so on, ad infinitum. But P2K seems somehow too weak. Second-order knowledge seems somehow more important than P2K alone would make it.

Then I read Sebastian Rödl’s Self-Consciousness, where (in Chapter 5) he argues that we need to distinguish two different types of knowledge, receptive knowledge and spontaneous knowledge, and understand the KK principle as claiming that, if you know something receptively, then you know spontaneously that you (receptively) know it. In other words, we need to replace the familiar formulation of the KK principle by a more careful formulation:

KKʹ: If you receptively know that p, then you spontaneously know that you receptively know that p.

Since the antecedent applies only to receptive knowledge, KKʹ won’t apply to your spontaneous knowledge that you receptively know that p, and so there’s no regress. Problem solved.

Or so I thought. I’ve now come to think that KKʹ is too strong. The problem here, of course, isn’t that there’s a regress; there isn’t. And it isn’t that I have any doubts about the distinction between receptive and spontaneous knowledge, or about the notion of spontaneous knowledge itself; I don’t. It’s that KKʹ amounts to the view that knowledge is necessarily self-conscious. And that doesn’t seem right to me. For one thing, non-rational/non-self-conscious animals seem to have receptive knowledge, but not spontaneous knowledge of their receptive knowledge. (I think it’s possible that they have some spontaneous knowledge; just not of their receptive knowledge.) If they do, then KKʹ is false. For another, I’m increasingly inclined to think that certain cognitive phenomena in human beings are plausibly construed as involving non-self-conscious knowledge—blindsight, for example, in which people seem to acquire information through visual perception, and in such a way that the information is non-accidentally accurate, and yet report having no knowledge of that information or of its acquisition through visual perception (in particular, they report having no visual experience of the relevant objects—though, again, there is evidence that they nonetheless acquire the information through the workings of the visual system).

So it’s interesting to me that, construed in terms of both spontaneous and receptive knowledge, P2K seems like a claim worth defending. It seems, in particular, like the kind of claim that I was looking for after reading Williamson, one intermediate in strength between KK and P2K, as stated above. Reformulated appropriately, P2K becomes:

P2Kʹ: It’s possible to spontaneously know that you receptively know that p.

P2Kʹ is a claim that some philosophers reject. For example, Quassim Cassam, in his book Self-Knowledge for Humans, argues that all self-knowledge is acquired through inference. So even if he allows that it’s possible to know, through inference, that you know that p (which, let’s say, you know through perception), he doesn’t allow that it’s possible to know spontaneously that you know that p. And this means that there’s an important disagreement between philosophers like Rödl and philosophers like Cassam that turns primarily on the truth or falsity of P2Kʹ, and not on the truth or falsity of KKʹ. And that means that, even if you like KKʹ, you might try to sway philosophers like Cassam by first trying to persuade them of P2Kʹ.

Not that that would be an easy task. Rödl describes spontaneous knowledge as knowledge acquired in a special way: to know spontaneously that you’re in some mental state is to know that you’re in that state by being in it. (So you can have spontaneous knowledge only of the mental.) And this idea is one that many philosophers find deeply mysterious (or so, at least, a great number of them have told me).

For my own part, I think the idea makes a lot of sense. As Rödl points out, it fits nicely with the fact that, if (bizarrely, I’ll grant you) someone asks you how you know you’re in pain, it’s tempting to reply (with considerable exasperation): “Because I’m in pain!”

But it’s interesting to note that, in order to make sense of this idea of spontaneous knowledge, of knowing that you’re in a state by being in it, we don’t need to accept the view that, whenever you’re in pain, you know that you’re in pain by being in pain. We don’t even need to accept the view that, whenever you’re in pain and know that you’re in pain, you know that you’re in pain by being in pain. We need only accept the view that, sometimes, when you’re in pain and know that you’re in pain, you know that you’re in pain precisely by being in pain.

The same is true of knowledge. In order to find an interesting application for Rödl’s notion of spontaneous knowledge, we don’t need to say that knowledge is necessarily self-conscious, i.e., that, whenever you receptively know that p, you spontaneously know that you do. Nor do we need to say that, whenever you receptively know that p and know that you do, the latter knowledge is spontaneous. We need only say that, sometimes, when you receptively know that p and know that you do, you know that you do precisely by receptively knowing that p.

That leaves certain questions open. For example: how much of our self-knowledge is spontaneous? Rödl says: “All of it.” (Well, not quite. He needn’t deny that you might have receptive knowledge of your receptive knowledge in addition to your spontaneous knowledge of your receptive knowledge. But he does say that, whenever you have any knowledge of your receptive knowledge, you have spontaneous knowledge of it.) Cassam says: “None of it.” I’m inclined to say: “Some of it.” As for exactly how much—that’s a question for empirical psychology.