Topics Knowledge

Question As I understand it, people use the word "believe" when they are somewhat but not entirely sure of a proposition (e.g., "I believe that he likes cheese", as opposed to "I know that he likes cheese"). If a person "believes" a proposition p, does he KNOW that he BELIEVES that p? Is he absolutely certain that he believes a proposition of which he is just somewhat certain? Or does he BELIEVE that he BELIEVES that p? (Are there other possible formulations?) -ace

Accepted:
July 21, 2007

Comments

You are right that people usually use the word `believe' only if they are not entirely sure. If they were, then they'd say something else, maybe "I know that...", or "I'm sure that...", or just "...", all by itself. But it does not follow that "I believe..." MEANS "I'm not absolutely certain", etc. This point is due to H.P. Grice and is central to his work on `conversational implicature'.

We also need to distinguish knowledge from certainty. It may likewise be true that people say "I know" only when they are fairly certain, but it does not follow that "I know..." means: I'm reasonably certain.... What knowledge is, well, that's a disputed question. But let's just pretend it's justified true belief. Then knowing is having a justified true belief, and you could know but not be certain you know, or even be very certain of something you truly believe but not know because you aren't really justified.

Most (though not all) philosophers would hold that, if you know that p, then you also believe that p---though, if you think you know, you won't SAY that you believe. To believe that p is to be in a certain mental state---that of regarding p as true, more or less. Exactly what mental state this is is a difficult question. But, again, most philosophers would hold that, if you do indeed believe that p, then---typically, though not always---you will also be in a position to know that you believe that p. Or, more generally, typically, though not always, you are in a position to know whether you believe that p.

Another question would be whether, if you believe that p, you are typically in a position to be rationally certain whether you believe that p. I don't know what views people hold on this question. Certainty isn't a terribly popular topic.