Knowledge

Knowledge means the things which are true, as opposed to opinion. Information which is correct is knowledge. Knowledge can always be supported by evidence. If a statement is not supported by evidence, then it is not knowledge. The evidence makes it justified.

Knowledge can refer to a theoretical or practical understanding of a subject. This was the point of Ryle's distinction between "knowing that" and "knowing how".^[1] It can be implicit (as with practical skill or expertise) or explicit (as with the theoretical understanding of a subject); it can be more or less formal or systematic.^[2] In philosophy, the study of knowledge is called epistemology. The philosopher Plato defined knowledge as "justified true belief". This definition is the subject of the Gettier problems.

All knowledge is a claim to be true, but the claim can be incorrect. The only claims (propositions) which are certainly true are circular, based on how we use words or terms. We can correctly claim that there are 360 degrees in a circle, since that is part of how circles are defined. The point of Aristotle's syllogism was to show that this kind of reasoning had a machine-like form:

• If all swans are white, and this is a swan, then it must be white.

But actually, in the real world, not all swans are white.

The most widely accepted way to find reliable knowledge is the scientific method. Yet one thing all philosophers of science agree is that scientific knowledge is just the best we can do at any one time. All scientific knowledge is provisional, not a claim of absolute truth.