By abstraction or generalization we simply consider in the concrete a particular property, quality, or attribute by itself, and take it _in universo_, without regard to anything else in the concrete thing. It must then be a real property, quality, or attribute of the concrete thing, or the abstraction will have no foundation in reality. But the universal is no property, quality, or attribute of particulars, the immutable of mutables, the eternal of things temporary, the necessary of contingents, the infinite of finites, or unity of multiples, otherwise particulars would be universals, mutables immutables, temporals eternals, contingents necessary, finites infinite, and multiples one--a manifest contradiction in terms. The generalization or abstraction of particulars is particularity, of mutables is mutability, of temporals temporality, of contingents contingency, of finites finiteness, of multiples plurality or multiplicity. The overlooking of this obvious fact, and regarding the universal, immutable, eternal, etc., as abstractions or generalizations of particulars, mutables, temporals, and so on, has given birth to the pantheistic philosophy, than which nothing can be more sophistical. The ideas or categories of the universal, the immutable, and the eternal, the necessary, the infinite, the one or unity, are so far from being abstractions from particular concretes that in point of fact we cannot even think things as particular, changeable, temporal, contingent, finite, or multiple without them. Hence, they are called necessary ideas, because without them no synthetic judgment _à posteriori_ or fact of experience is possible. They are not abstractions formed by the human mind by contemplating concrete things, because the human mind cannot operate or even exist without them, and without them human intelligence, even if supposable, could not differ from the intelligence of the brute, which, though many eminent men in modern science are endeavoring to prove it, cannot be accepted, because in proving we should disprove it. {155} The question now for philosophy to answer, as we have already intimated, is, Are these ideas or categories, which precede and enter into every fact of experience, forms of the subject or human understanding, as Kant alleges, or are they objective and real, and, though necessary to the existence and operation of the human mind, are yet really distinct from it, and independent of it, as much so as if no human mind had been created? This is the problem.