In epistemology, a self-evident proposition is a proposition that is known to be true by understanding its meaning without proof, and/or by ordinary human reason. Some epistemologists deny that any proposition can be self-evident.

What means self-evident?

: evident without proof or reasoning.

What is an example of a self-evident fact?

The truths of mathematics, for example, are often thought of as self-evident. One plus one equals two. You don't need to go all over the world counting things to prove this. In fact, one plus one equals two is something you need to believe before you can count at all!