Skeptics argue that belief in something does not justify an assertion of knowledge of it. In this, skeptics oppose foundationalism, which states that there are basic positions that are self-justified or beyond justification, without reference to others.

What did the skeptics believe?

The core concepts of ancient skepticism are belief, suspension of judgment, criterion of truth, appearances, and investigation. Important notions of modern skepticism such as knowledge, certainty, justified belief, and doubt play no or almost no role.

Do skeptics believe in free will?

Most philosophers believe that almost all normal human beings possess free will, but a minority are skeptics. The most influential contemporary skeptics argue that free will is incompatible with both determinism and indeterminism. ...