Page:Biographia literaria; or, Biographical sketches of my literary life and opinions (IA biographialitera04cole).pdf/259

 by a point without it, and then it must flow back again on itself, that is, there arises a cyclical line, which does inclose a space. If the strait line be assumed as the positive, the cyclical is then the negation of the strait. It is a line, which at no point strikes out into the strait, but changes its direction continuously. But if the primary line be conceived as undetermined, and the strait line as determined throughout, then the cyclical is the third compounded of both. It is at once undetermined and determined; undetermined through any point without, and determined through itself. Geometry therefore supplies philosophy with the example of a primary intuition, from which every science that lays claim to evidence must take its commencement. The mathematician does not begin with a demonstrable proposition, but with an intuition, a practical idea.

But here an important distinction presents itself. Philosophy is employed on objects of the, and cannot, like geometry appropriate to every construction a correspondent outward intuition. Nevertheless philosophy, if it is to arrive at evidence, must proceed from the most original construction, and the question then is, what is the most original construction or first productive act for the. The answer to this question depends on the direction which is given to the