That in such a concept no contradiction must be contained is, to be sure, a necessary logical condition; but it is far from sufficient for the objective reality of the concept,.e., for the possibility of such an object as is thought through the concept, Thus in the concept of a figure that is enclosed between two straight lines there is no contradiction, for the concepts of two straight lines and their intersection contain no negation of a figure; rather the impossibility rests not on the concept in itself, but on its construction in space,.e., on the conditions of space and its determinations; but these in turn have their objective reality,.e.