Certainty

Certainty is the state of being sure an idea is correct. CF rejects certainty in the strong sense — and treats certainty in the weak sense (subjective confidence) as a separate, manageable thing.

Strong certainty — rejected

CF rejects the view that any idea can be certainly true:

• The regress shows no justification chain ends successfully.
• Universal premises are fallible.
• Even infallibilism about logic and math fails by CF's analysis.

Weak certainty — accepted but carefully bounded

CF accepts that you can feel certain about something. But:

• Feeling certain doesn't make it true. A confident error is still an error.
• Certainty can block criticism. Feeling sure makes it harder to hear criticism.
• CF recommends acting on non-refuted ideas, not on feelings of certainty.

Certainty vs. confidence

CF distinguishes certainty about the world (impossible) from confidence in your own epistemic situation (manageable). You can be confident:

• That you haven't yet found a criticism of X.
• That you've made a reasonable effort to look.
• That you would notice obvious criticisms.

These are uncertainty-handling claims, not world-claims about truth.

"It's also impossible to (correctly) be 99% or even 1% sure of an idea's truth." — criticalfallibilism.com