JMC : Logic and Mental Philosophy / by Charles Coppens, S.J.

Chapter IV.
The Constituent Elements of Matter.

126. We may consider matter as extended substance possessed of different powers according to its different species; or we may consider it as to its further constituent elements of potentiality and activity, whatever be its species. Considered in the former way, matter is divisible into homogeneous particles, i.e., into particles of the same nature as the entire mass. Many species of matter can be further dissolved into chemical particles, which are heterogeneous, i.e., of different natures; thus, water can be decomposed into oxygen and hydrogen. Oxygen, hydrogen, etc., are not known to be further resolvable into other particles; they are called simple elements, not as if their particles had no extension, but to distinguish them from the molecules of chemical compounds.

127. We are now to investigate the ultimate composition of bodies, even of molecules of matter, whether they be chemically simple or compound. The following is the explanation given by Plato, Aristotle, St. Thomas, and by the Schoolmen generally; it is called the system of matter and form.

Every one of the smallest particles into which a non-living body may be divided possesses, just like the whole mass, certain powers or energies, e.g., affinities, attractions, etc.; for matter without powers would be a useless being, and a wise God creates nothing useless. The source of these powers, the active principle in matter, is called its form; by it a substance is constituted such a substance, and different from every other; it is therefore its substantial form. In living bodies the source of their energies is not in each separate particle, but in the one life principle which determines the species of each plant or animal; of the vital form we shall treat in Psychology (Nos. 139, etc.).

Besides the forms, which differ for the different species of bodies, there is something which is the same in all material substances, viz., the principle of extension; it is matter in its first abstract entity, and may be called the potential principle, the prime matter, or materia prima of the Schoolmen. It cannot exist by itself without some form, for all matter is some kind of matter. This potential principle thus informed by the active principle is, in its ultimate particle which we are now considering, a natural or physical unit; it naturally occupies some space which has extension in length, breadth, and thickness. But being a physical unit, though extended, the ultimate particle is not physically divisible into smaller parts. The space, however, which each particle occupies is indefinitely divisible. For instance, when hydrogen and oxygen unite to constitute a molecule of water, their potential principle remains, but their active principles cease to exist as such and are succeeded by a new active principle, that of water.

128. This form of water is said to be educed out of the potentiality of matter -- i.e., that same prime matter which before was of the nature of oxygen and hydrogen now becomes of the nature of water; before the change it was in potentiality to become water, now it is actually water; somewhat as a cubic block of wax can become a ball of wax. The change of a square block to a ball of wax is a change of an accidental form, that of one substance into another is a change of the substantial form. The active principles of the simple elements do not, as such, or formally, remain in the compound, yet they may be said not to have perished altogether; they exist still in the power or virtue of the compound, which can reproduce them, just as the bail of wax can become a square lump again.{1}

129. If from a mass of non-living matter any physical particle be detached, it remains of the same nature as the mass, and has its own potential and active principle, its matter and term; but in a living mass, an organized body, be it plant or primal, while the potential principle of all the particles remains, all the forms which may have informed the single particles, before being taken into the organism, have ceased to exist as web, and are replaced by the one active principle or form which is the vital principle of the plant or animal. It is the term that constitutes any material substance in its species; from the form proceed all its powers of action; the properties which a body derives from the potential principle are extension, divisibility, and, in general, whatever is common to all matter. In a crystal there appears to be one principle of action pervading and thus unifying the whole mass, building up the structure on one plan; in this crystals appear to agree with living beings, though, as we shall explain in Psychology, they differ from them in many essential respects. (See No. 140.)

130. Two other systems of explaining the constituent elements of matter are advocated by other schools of philosophy. the dynamic theory, not unknown to the ancients, after being remodeled by Leibnitz, owed its first popularity to the further improvements made in it by Roger Boscowich, S.J., and later by Kant. It teaches that the ultimate elements of matter are simple unextended particles, called monads (monas, unit), all of which are homogeneous, and endowed with powers of attraction and repulsion. As each of them occupies only a mathematical point, no number of them could ever make up any bulk, or produce extension, except for their mutual repulsion; and they are kept together by mutual attraction.

131. The atomic theory teaches, as its fundamental truth, that the ultimate particles are extended and yet indivisible; they are called atoms (atomos, indivisible). This system agrees with the scholastic in affirming that there are ultimate particles of matter which are extended and yet cannot be physically or chemically divided into smaller particles. But it differs from the scholastic theory in denying that the atoms consist of a potential and an active principle, the active principle constituting the specific difference of bodies. It gives no satisfactory reason why the extended atoms are not divisible, since it supposes that they are not constituted as units by a simple form which demands a definite size as well as it demands definite powers. Nor does that theory explain satisfactorily the specific powers of bodies, e.g., of iron and gold. Some writers suppose that the atoms differ specifically, but attempt no explanation; others suppose that the difference consists only in the figure, size, or motion of the atoms.

132. Thesis VII. There are in matter two substantial principles, that of extension and that of specific action.

Proof. Bodies can undergo substantial changes; but they could not do so if there were not two substantial principles, that of extension and that of specific action; therefore these exist.

We prove the major. Bodies can undergo substantial changes -- e.g., water is not a mere mixture of hydrogen and oxygen, but it is a new substance into which the elements are changed. This truth is proclaimed by common sense, by the languages of all nations, and even by the manner of speaking of those very philosophers who implicitly deny this fact; few will attempt to deny it explicitly. In fact, all draw a distinction between a mere mixture, e.g., the atmospheric air, and a chemica1 compound.

We prove the minor. No substantial change of matter is possible unless there be two substantial principles. For in a substantial change something substantial must remain, else there would be a creation of the new substance, not a change from the old; and something substantial must go and come, or be exchanged; for if what is exchanged is only accidental, e.g., figure, arrangement of parts, etc., then the change is accidental and not really substantial. Now, it is noticed that extension always remains, and the specific powers are changed; therefore there are in matter two substantial principles, that of extension and that of specification.

133. It will be noticed, on careful consideration, that neither the dynamic nor the atomic theory can satisfactorily account for truly substantial changes; for both admit only one substantial principle, which the dynamic calls simple and the atomic extended, but which both theories suppose to be permanent; so that what is changed in the formation of new substances is only the accidents of quantity, figure, motion, etc. If such were the fact, the new bodies would not differ substantially from their elements.

Besides, the dynamic theory does not account for extension; for no number of simple monads can fill a space; and the supposition that those monads possess attraction and repulsion does only attribute to one principle two contrary effects, which is anything but scientific. On the other hand, the atomic theory does not explain how the atoms can be extended and have certain figures, and yet cannot be separated into parts; nor does it account scientifically for the specific differences.

It belongs to Chemistry to study the phenomenal properties of the simple elements, but to Metaphysics to go back of the phenomenal and study the inmost essences of things material and immaterial. In doing so, the metaphysician must take into account all that the phenomenal can teach him. If he is mistaken about the effects, he is apt to misunderstand the nature of the causes. It is, therefore, not a little remarkable that the theory of matter and form, laid down in ages when the physical phenomena were so little understood, should still to-day account more plausibly than any other for all the facts which Chemistry, Biology, and other modern sciences have discovered. And yet such is the case, as is proved by Father Harper in his Metaphysics of the Schools (vol. ii. b. v. c. ii. § 4).

{1} Chemists claim, besides, that some of the properties of the simple substances are preserved in the compounds, in particular their chemical affinities: so that in a molecule or atom of water the affinities of hydrogen and oxygen condense in a manner to exist. They add that spectral analysis shows that the 'spectra' of the simples do not altogether vanish from the 'spectra' of the compounds. (See Pesch, Institutiones Philosophiae Naturalis, No. 130.)

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