I act with complete certainty. But this certainty is my own.

At the core of all well-founded belief lies belief that is unfounded.

If you tried to doubt everything you would not get as far as doubting anything. The game of doubting itself presupposes certainty.

Don't get involved in partial problems, but always take flight to where there is a free view over the whole single great problem, even if this view is still not a clear one.

A philosophical problem has the form: I don't know my way about.

The agreement or disagreement or its sense with reality constitutes its truth or falsity.