The awareness of the ambiguity of one's highest achievements, as well as one's deepest failures is a definite symptom of maturity.
Paul TillichOur search for such [moral] principles can start with . . . the unconditional imperative to acknowledge every person as a person. If we ask for the contents given by this absolute, we find, first, something negative-the command not to treat a person as a thing. This seems little, but it is much. It is the core of the principle of justice.
Paul TillichThere is faith in every serious doubt, namely, the faith in the truth as such, even if the only truth we can express is our lack of truth.
Paul Tillich