Substance (Lat. sub, under, sto or stans, to stand) is literally that which subsists by itself. In Greek. substance is denoted by οὐσία; hence, that which truly is, or essence, seems to be the proper meaning of substance. It is opposed to accident; of which Aristotle has said that you can scarcely predicate of it that it is anything. Our first idea of substance is probably derived from the consciousness of self-the conviction that, while our sensations, thoughts, and purposes are changing, we continue the same. We see bodies, also, remaining the same as to quantity or extension, while their color and figure, their state of motion or of rest may be changed. — Substances are either primary, that is, singular, individual substances; or secondary, that is, genera and species of substane. Substances have also been divided into complete and incomplete, finite and infinite. But these are rather divisions of being. Substance may, however, be properly divided into matter and spirit, or that which is extended and that which thinks. Substance is given by Aristotle as one of the four principles common to all spheres of reality; the other three being form or essence, moving or efficient cause, and end. He says, further, that the individual alone has substantial existence, and defines οὐσία, in the sense of the individual substance, as that which cannot be predicated of anything else, but of which anything else may be predicated. Johannes Philoponus of Alexandria, by extending the Aristotelian doctrine, that substantial existence is to be predicated in the fullest sense only of individuals, to the dogma of the Trinity, thereby incurred the accusation of tritheism. John Scotus regarded the Deity as the substance of all things, and could not, therefore, regard individual, concrete things as substances, of which the general may be predicated and in which the accidental is contained. He views all things, rather, as contained in the divine substance. Berengarius of Tours (De Sacra Cenan) disputes the theory of a change of substance, claimed by the advocates of transubstantiation, without a corresponding change in the accidents, i.e. a change in the bread and wine apparent to the senses. Roscelinus teaches that whatever is a substance is, as such, not a part; and the part is, as such, not a substance, but the result of that subjective separation of the substance into parts which we make in [thought and in] discourse. Gilbertus thus speaks: The intellect collects the universal, which exists, but not as a substance (est, sed non substat), from the particular things which not merely are (sunt), but also (as subjects of accidents) have substantial existence, by considering only their substantial similarity or conformity.
Descartes defines substance as follows: "By substance we can only understand that which so exists that it needs nothing else in order to its existence," and adds that, "indeed, only one substance can be conceived as plainly needing nothing else in order to its existence, namely, God; for we plainly perceive that all others cannot exist without God's assistance." Spinoza understands substance to be "that which is in itself, and is to be conceived by itself. There is only one substance, and that is God. This substance has two fundamental qualities or attributes cognizable by us, namely, thought and extension; there is no extended substance as distinct from thinking substance." "There are not two substances equal to each other, since such substances would limit each other. One substance cannot produce or be produced by another substance. Every substance, which is in God's infinite understanding, is also really in nature. In nature there are not different substances; nature is one in essence, and identical with God." Locke says, "The mind, being furnished with a great number of simple ideas, conveyed to it by sensation and reflection, remarks that a certain number of them always go together; and since we cannot imagine that which is represented by them as subsisting by itself, we accustom ourselves to suppose a substratum in which it subsists, and from which it arises; this substratum we call a substance. The idea of substance contains nothing but the supposition of an unknown something serving as a support for qualities." Leibnitz gives the name monad to simple, unextended substance; that is, a substance which has the power of action; active force (like the force of the strained bow) is the essence of substance. He held that the divisibility of matter proved that it was an aggregate of substances; there can be no smallest indivisible bodies or atoms, because these must still be extended, and would therefore be aggregates of substances; that the real substances of which bodies consist are indivisible, cannot be generated, and are indestructible, and in a certain sense similar to souls, which he likewise considers as individual substances. The individual, unextended substances were termed by Leibnitz monads. Hume remarks, "We have no clear ideas of anything but perceptions; a substance is something quite different from perceptions; hence we have no knowledge of a substance. The question whether perceptions inhere in a material or immaterial substance cannot be answered, because it has no intelligible sense." John Stuart Mill distinguishes substances as bodily and mental, and says, "Of the first, all we know is, the sensations which they give us, and the order of the occurrence of these sensations; i.e. the hidden cause of our sensations. Of the second, that it is the unknown recipient of them." See Fleming, Vocab. of Philosoph. Sciences, s.v.; Ueberweg, History of Philosophy (see Index).
Substance, a term used in technical divinity to describe nearly the same idea as essence or nature. Thus the Son is said to be the same substance with the Father , that is, truly and essentially God, as the Father is. SEE CHRISTOLOGY.