/lit/ - Literature

Skeptical philosophers always resort to faith and belief instead of justification, which they claim is impossible, to ground their interpretation of the world. But how can you resort to belief when you don't even know if you have a faculty of belief, or if beliefs exist? If that is the case, then you can't ground your interpretation like that. Jacobi and Kierkegaard seem to do this without showing it's valid. How do you fix this?
Is there any grounds for justification or certainty?