An honest religious thinker is like a tightrope walker. He almost looks as though he were walking on nothing but air. His support is the slenderest imaginable. And yet it really is possible to walk on it.

Nicholai Hartman suggested the well-known distinction between ‘systematic thinking’ and ‘problem thinking’. Whereas the former begins from a series of assumptions and proceeds to offer all-encompassing solutions, the latter begins from a problem and considers it in depth, without striving for comprehensive systems. Problem thinking is dialectical – it appraises the boundaries of the problem and the limitations of its solutions. According to Hartman, a typical instance of a systematic thinker is Spinoza, who created an inclusive metaphysical system based on primary and irrefutable assumptions. A classic example of problem thinking is the philosophy of Plato, which is more intent on clarifying the predicament than on offering solutions, and hence its dialectic character.