I. _Empiricism._ 37.] Under these circumstances a double want began to be felt. Partly it was the need of a concrete subject-matter, as a counterpoise to the abstract theories of the understanding, which is unable to advance unaided from its generalities to specialisation and determination. Partly, too, it was the demand for something fixed and secure, so as to exclude the possibility of proving anything and everything in the sphere, and according to the method, of the finite formulae of thought. Such was the genesis of Empirical philosophy, which abandons the search for truth in thought itself, and goes to fetch it from Experience, the outward and the inward present. The rise of Empiricism is due to the need thus stated of concrete contents, and a firm footing--needs which the abstract metaphysic of the understanding failed to satisfy. Now by concreteness of contents it is meant that we must know the objects of consciousness as intrinsically determinate and as the unity of distinct characteristics. But, as we have already seen, this is by no means the case with the metaphysic of understanding, if it conform to its principle. With the mere understanding, thinking is limited to the form of an abstract universal, and can never advance to the particularisation of this universal. Thus we find the metaphysicians engaged in an attempt to elicit by the instrumentality of thought, what was the essence or fundamental attribute of the Soul The Soul, they said, is simple. The simplicity thus ascribed to the Soul meant a mere and utter simplicity, from which difference is excluded: difference, or in other words composition, being made the fundamental attribute of body, or of matter in general. Clearly, in simplicity of this narrow type we have a very shallow category, quite incapable of embracing the wealth of the soul or of the mind. When it thus appeared that abstract metaphysical thinking was inadequate, it was felt that resource must be had to empirical psychology. The same happened in the case of Rational Physics. The current phrases there were, for instance, that space is infinite, that Nature makes no leap, &c. Evidently this phraseology was wholly unsatisfactory in presence of the plenitude and life of nature.