Epistemology is the study of knowledge and justified belief. It is concerned with the nature, sources and limits of knowledge.
“Wisdom is knowing how little we know.”
Epistemology has been primarily concerned with propositional knowledge, that is, knowledge that such-and-such is true, rather than other forms of knowledge, for example, knowledge how to such-and-such.
There is a vast array of views about propositional knowledge (knowledge which requires no actual experience), but one virtually universal presupposition is that knowledge is true belief, but not mere true belief.
For example, lucky guesses or true beliefs resulting from wishful thinking are not knowledge. Thus, a central question in epistemology is: what must be added to true beliefs to convert them into knowledge?
This question is generally discussed in a debate between rationalism and empiricism, or the question of whether knowledge can be acquired a priori or a posteriori:
- Empiricism: knowledge is obtained through experience.
- Rationalism: knowledge can be acquired through the use of reason.