We are schooled in various dichotomies dividing up the field of human knowledge: a priori versus a posterioriknowledge, infallible versus fallible knowledge, implicit versus explicit knowledge, innate versus acquired knowledge, basic versus derived knowledge, and so on. These are all worthy of the attention of the epistemologist, and have duly received it. I propose to introduce a new dichotomy that has not been investigated, nor even recognized: the distinction between what I shall call forced knowledge and optional knowledge.
By optional knowledge I mean the kind that is acquired intentionally, or which can be so acquired. Scientific knowledge is a good example: procedures are undertaken that result in knowledge, and these procedures are followed voluntarily—experiments, observations, calculations, etc. Also commonsense knowledge: if I acquire knowledge about what is in the next room, by going in there to have a look, then I am acquiring optional knowledge. Optional knowledge is the kind you are free to acquire or not to acquire: you can choose knowledge or ignorance. You can open or close your eyes, block your ears or not, smell or refuse to, taste or decline to. Nothing compels you to know the things known by these methods. You can learn mathematics or not bother, study history or give it a miss, fill your head with geographical facts or remain a geographical ignoramus. Education consists of exercising the ability to gain optional knowledge; the will is involved, along with hard work and dedication. A great deal of knowledge is knowledge that you could have failed to have—knowledge that does not come with the territory, but enters by decision and action. You have the option of not knowing, though you may also choose to know.
By forced knowledge I mean knowledge that you can’t help having, that you can’t avoid, that is not a matter of will. You have it whether you like or not; it is built into you, not brought to you. It is involuntary, inescapable, and automatic. The knowledge is forced upon you; you have no say in the matter. The most obvious example of forced knowledge is innate knowledge—knowledge you are born with, so not acquired intentionally. This is knowledge you cannot decline to possess. But that is not the most interesting example of the type: there is also knowledge of one’s own mind. You cannot decline to learn about, and acquire knowledge of, your current conscious inner states—you are condemned to know about these things. There is no escape, no avoidance, and no decision. Like it or not, you have to know about your own inner life; this is not something to which you can turn a blind eye or a deaf ear. It cannot be turned off or shut down or otherwise disrupted. It is self-intimating in the sense that it automatically, necessarily, registers on you: it imposes itself on you. You are, as it were, its victim. 
It is not the same with any unconscious mental states that you might have: these do not produce forced knowledge, since they are hidden from awareness. You can choose to know about your unconscious mind or choose not to. But you cannot choose to know about your conscious mind. This is not because the conscious mind is identical with knowledge of itself, so that knowledge comes with the conscious mind trivially. States of consciousness and knowledge of such states are distinct existences: pain, for example, is not identical with knowledge of pain. Still, there cannot be pain without knowledge of it; you cannot decide to know nothing more of your pain, as you can decide to know nothing more of someone else’s pain. There is, so to speak, no gap between consciousness and knowledge of it, such that that gap can be turned into ignorance—as there is a gap between my knowledge and your consciousness. The knowledge in my own case is immediate and therefore unavoidable.
Among the objects of this type of forced knowledge we can distinguish four broad categories: sensations, thoughts, emotions, and meanings. We cannot avoid knowing about our sensory states and bodily sensations; we cannot avoid knowing what we are thinking; we cannot avoid knowledge of our emotions; and we cannot avoid knowing what we mean by our words. Each of these kinds of epistemic forcing has consequences for the nature of our psychological life: we must know what it is like for us perceptually at any given moment; we cannot shield ourselves from our own thoughts; we always know our state of emotional wellbeing; and we cannot fail to know what meaning we are trying to communicate. So we have to contend both with the conscious state itself as well as the distinct state of knowing about it. For example, we have both the emotion of depression and the knowledge that we are depressed: both contribute to our overall psychological state (similarly for joy and so on). In the case of meaning we must have a complex of communicative intentions plus self-knowledge with regard to those intentions–and these are inseparable. Thus we cannot help knowing what we mean by what we say: that is part of what meaning is. The theory of meaning must therefore acknowledge that meaning involves forced knowledge: the speaker must know what she means, even though the hearer may or may not know it. I can decide to find out what you mean, but I cannot decide to find out what I mean—I am condemned to semantic self-knowledge. Meaning is something such that the agent of it must know what she is agent of. No one can mean something and be in the dark about what she means. 
Forced knowledge is not the same as infallible knowledge. A person has infallible knowledge when her beliefs cannot fail to be true; a person has forced knowledge when she must have certain beliefs—that also happen to be true. In the case of forced knowledge, there isn’t the option of suspending belief, but in the case of infallible knowledge there is that option. Descartes teaches us that whenever we believe that we think we do think, but this is not the same as to say that we cannot help believing that we think. Similarly for existence: infallible knowledge of our existence is not the same as forced knowledge of our existence. It is true that the two tend to go together, since both characterize knowledge of the inner; but they are different concepts. I cannot avoid the knowledge that I exist—this is part of what it is for me to exist—and my belief that I exist cannot fail to be true. But I might be infallible about my existence without having it always before me. Descartes could have added to the Cogito: “I exist, therefore I know my existence”. I can avoid knowledge of the existence of others, simply by hiding away somewhere; but I cannot hide from my own existence—it is always evident to me. I am forced to know that I exist for as long as I (consciously) exist. I am also forced to know what I feel, think, and mean, whenever I do or undergo any of these things. I cannot shield myself from such knowledge, or lazily fail to pick it up, or simply turn my mind to other things. It is impossible for me to be ignorant about these things.
We usually don’t like being forced into things; we value our freedom. We accordingly might resent epistemic bondage—why should I be forced to know things I would rather not know? I don’t want to know that I am depressed or angry or have compulsive thoughts or say mean things to people—but I am forced to know these things against my will. If someone offered me the chance to avoid such self-knowledge, I might well take it: my life might be happier that way. We avoid knowledge of the mental states of others where it is convenient, so why not avoid knowledge of our own mental states when it suits us? It would nice to be able to turn it on and off at will. That way we would increase our freedom. But this is a fantasy of freedom: it is a deep fact about the human condition that we are condemned to self-knowledge—as we are condemned to other-speculation. It is difficult to acquire knowledge of the minds of others, maybe impossible, but it is all too easy to acquire knowledge of one’s own mind: the former is distinctly optional, the latter utterly forced. We can glide over the minds of others or ignore them entirely; but we cannot avoid the reality of our own mind—we are compelled to know ourselves (in our conscious part). The oracle commanded, “Know thy self!” but in one sense the response must be, “How can I not?” The oracle might be interpreted to mean: “In addition to forced self-knowledge, there is also optional self-knowledge you really should try to obtain, concerning things that lie outside of your immediate awareness”. Perhaps the oracle was being partly ironic, since it must have been well aware of the inescapability of self-knowledge of a very ordinary kind.
It would be nice to have a theory of why self-knowledge is forced: what is it about the conscious mind that compels knowledge of it? And do other animals have the same kind of non-optional knowledge? What kind of knowledge is it—how conceptual is it? Is it anything like perception? Is it causal? Is it reason-based? These are general questions about introspective knowledge, well recognized; we need to add the question of force—what makes introspective knowledge forced knowledge? My aim has been to identify the category and illustrate it with the example of self-knowledge. 
 Two other candidates for forced knowledge are logical knowledge and proprioceptive knowledge. A good case could be made that knowledge of basic logic is unavoidable: we are forced to recognize the validity of certain kinds of inference, since this is constitutive of being a thinker at all. I cannot choose to be ignorant of modus ponens, say. In the case of the proprioceptive sense, we cannot turn if off as we can the other senses: I can’t, at will, block my sensory access to the position of my body, as I can close my eyes or stop up my ears. I might be able to block proprioceptive knowledge by undertaking brain surgery or going to sleep, but I cannot in the normal course of events avoid this kind of knowledge. The concept of forced knowledge thus gathers a quite diverse group of knowledge types, not gathered by other epistemic notions.
 There is a question about whether we can choose to attend to our inner states, or not attend to them. I might choose not to attend to a mild pain in my arm—so I don’t suffer from forced attention in such a case. This doesn’t mean I can choose not to know about the pain, since knowledge can be acquired without the use of attention; and there are limits to how inattentive I can be to my inner states—I can’t choose not to attend to an intense pain or a compulsive thought. In the special case of meaning, it is difficult to see how we could mean something and fail to attend to what we mean: communicative speech acts require attention (probably because of the nature of the intentions involved). In general, however, attention is more optional than knowledge—attending is an act.
 I hope it is clear that I am not saying that it is possible to “decide to know” in the sense in which it has been denied that we can “decide to believe”. We cannot, in this sense, decide to know or believe—and the concept of optional knowledge is not intended to conflict with that. The point is rather that we can decide to find things out, or decide not to—that is, undertake procedures that will produce knowledge and belief. In the case of forced knowledge, however, we cannot decide to find things out, or decide not to; we will be supplied with the knowledge anyway. The acquisition of knowledge is unavoidable in the one case but not in the other.