Self-evidence

In epistemology, a proposition that cannot be understood without knowing that it is true, is called a self-evident proposition. A self-evident proposition is one that can be known to be true without proof (but only if one understands what it says). Some epistemologists deny that any proposition can be self-evident.

My belief that I am conscious is considered by many to be self-evident; your belief that I am conscious is not.

In informal or colloquial speech, "self-evident" often merely means "obvious."

Certain forms of argument from self-evidence are considered fallacious or abusive in debate. An example is the assertion that since an opponent disagrees with a (claimed self-evident) proposition, that he must have misunderstood it.

See also: the concepts of fundamental object and axiom in mathematics.