A system, which aims to deduce the memory with all the other functions of intelligence, must of course place its first position from beyond the memory, and anterior to it, otherwise the principle of solution would be itself a part of the problem to be solved. Such a position therefore must, in the first instance be demanded, and the first question will be, by what right is it demanded? On this account I think it expedient to make some preliminary remarks on the introduction of Postulates in philosophy. The word postulate is borrowed from the science of mathematics [50]. In geometry the primary construction is not demonstrated, but postulated. This first and most simple construction in space is the point in motion, or the line. Whether the point is moved in one and the same direction, or whether its direction is continually changed, remains as yet undetermined. But if the direction of the point have been determined, it is either by a point without it, and then there arises the straight line which incloses no space; or the direction of the point is not determined by a point without it, and then it must flow back again on itself, that is, there arises a cyclical line, which does enclose a space. If the straight line be assumed as the positive, the cyclical is then the negation of the straight. It is a line, which at no point strikes out into the straight, but changes its direction continuously. But if the primary line be conceived as undetermined, and the straight 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.