What is it to know
something? When does someone actually know something
What can be known? What distinguishes true knowledge
from false knowledge
These are questions of epistemology
There are three necessary conditions for knowledge.
- Knowledge requires truth. You can't 'know that P' if P is
false. You can think you 'know that P' when P is false, but you
can't realy 'know that P' unless P is true. No matter how hard one
believes, grass is not purple.
- Knowledge requires you to believe it. To say that someone knows that P
implies (among other things) that he believes that P.
- Just because you believe that P, and P happens to be true, doesn't
necessarily mean that you know that P. Consider a clock.
Do you know that it is 11:43? Are you justified in this belief?
- You look a and see that it reads 11:43
- You believe that it is 11:43
- It happens to be 11:43
- The clock stopped last week at 11:43
Justification is the most controversial part of knowledge requirements.
There are two types of justification:
Some beliefs are useful because they will help you get ahead in life.
These beliefs are pragmatically justified. From a practical
point of view, they are good beliefs to have. This does not show, however,
that those beliefs are epistemically justified.
Having justification does not mean that you have to belief it. It is
quite possible (and common) that people have justifications for things
that run counter to their beliefs.
It also takes more than a belief to be justified than just having
justification for believing it. Imagine that you have substantial
evidence for believing that Oswald shot
JFK, yet you are a conspiracy
freak that you don't believe it. One day, your gypsy aunt holds a
seance in which you "speak" to the dead Oswald and thereby "discover"
that he acted alone. On the basis of this experience, you believe
that Oswald acted alone. You have believe that P, you have good
reasons for believing that P, but those aren't the reasons on which
you base your believe. The basis of the belief is on bad
reasoning. Thus, in this case, it could be said that your belief
is unjustified, even though the proposition that Oswald acted alone
is one you have good justification for.
Do not confuse justification with justifying arguments. When asked
if a belief is justified, the question is one of if its epistemically
reasonable for that belief to be held. It is not a question of if
an explicit justifying argument can be given.