There are many attempts to define knowledge in the history of philosophy. but before i describe one, ask yourself whether you need to know that you know P in order to know P. if you can know without knowing how you know, then you don't need to worry about any of this. of course, you could never be sure that you really did know P or not, unless you knew how you knew it.
so here's the basic four part definition of knowledge, used in a rough way by most philosophers (P means a proposition, S is any subject or person):
For P to be an item of knowledge
1) S must believe that P
2) P must be true
3) S must be justified in believing that P
4) the justification must attach to the truth or facts of the matter in the correct way.
so what does this mean?
well, 1 is necessary since if you know something, you must also believe it. 2 is necessary because if P isn't true, then S has a mistaken belief, rather than knowledge.
3 is where it gets interesting... since someone could believe something that is true, but not know about it, if they believe it for the wrong reasons, or no reason at all. if that is the case, it is just an accidental true belief rather than knowledge.
4 is the most controversial point. Gettier, a philosopher who did nothing for the rest of his life, made this point, which destroyed the three point definition that had been around since plato:
one can have a justified true belief, and still not have knowledge, in the following way...
jones comes into the office everyday and looks at the clock on the wall everyday, and everyday the clock shows the correct time. one day jones comes into the office at exactly nine o'clock, looks at the clock which says 9:00 exactly, and believes, justifiably (due to the previous observations of the clock), that it is nine exactly. so this is a justified true belief. unfortunately the clock stopped at 9:00pm the previous night, so had jones have come in a minute earlier or later, he would still have the same belief, but it wouldn't be true. thus the facts in the world have to connect to the justified belief in the correct way. what is the correct way? well, no-one can agree on that yet  |
Nonetheless, coincidentally I've been talking about this whole truth business with some friends for the past couple weeks. Mostly it was from a religious standpoint (the truth about god and life after death) but it soon sprawled out to cover reality and the universe. I pretty much agree with the idea that we're all equally ignorant. I'm very frustrated lately thinking how everything I 'know' could be a lie or an illusion and we can never really 'know' the truth and that everything really is based on faith and that is the only bit of truth in the universe. It sucks because I try to find truth in an objective sense and look beyond God and the known universe but finally I decided that any 'true' answers, if they're even out there, can never be attained because we can never know what doesn't exist which doesn't mean it doesn't, but that it's just impossible<--I hate that word. Oh well, forgive the rambling of a young 16-year old, just a byproduct of american education 
