A History of Mediaeval Jewish Philosophy

by Isaac Husik

Spiritual things also have matter and form. In corporeal artificial things like ring or bracelet, the matter is gold, the form is the form of ring or bracelet, the efficient cause is the art of the goldsmith, the final cause or purpose is the adornment. In spiritual things we may compare genus to matter, species to form, specific difference to efficient cause, the individual to the final cause.

Everything exists either by itself (per se) or in something else. Matter exists by itself, form exists in something else, in matter. Matter is potentially substance; after it assumes a form it becomes actual substance. In reality there is no matter without form, but in thought we can remove the form and leave the matter.

Substance may be described as that which bears opposite and changing qualities. No substance can be the opposite of another substance through its substantiality, but through its accidents; for opposition resides in quality. Matter receiving form is substance. Absolute substance is simple and spiritual, for it cannot be perceived through the five senses. When the philosophers say that all body is substance, and that the individual is a substance, they use substance in contradistinction to accident, meaning that the individual exists by itself, and needs not another for its existence, unlike accidents, which must have something to exist in.

This absolute substance, which is simple and spiritual, seems to be identical with Gabirol's "substantia quæ sustinet decem prædicamenta," the substance which supports the ten categories. Gabirol means by it that which remains of a corporeal substance when we take away from it everything that qualifies it as being here or there, of a particular nature or size, in a given relation, and so on.

The expression corporeal world includes the celestial spheres and all which is under them. To be sure, the body of the sphere is different from the other bodies in matter and form and qualities. It consists of a fifth nature, different from the four elements. It is not cold, or it would move downward like earth and water. It is not warm, or it would move upward like air and fire. It is not wet, for it would then roll like the waves of the sea. Nor is it dry, for it would condense and not move at all. Not being any one of these qualities, which constitute our four elements, the sphere is not a composite of them either; for the simple is prior to the composite, and we cannot regard the elements of the sublunar world as prior and superior to the spheres.

The sphere is neither light nor heavy. For light and heavy are relative terms. An object is heavy when out of its natural place, light when in its natural place. Thus a stone is heavy when it is away from the earth, which is its natural place, but is light when it comes to rest where it belongs. The sphere is never out of its place or in its place, as it moves constantly in a circle. Hence it is neither light nor heavy.

Ibn Zaddik's definition of light and heavy as being relative, and dependent on the relation of the object to its natural place is peculiar, and would lead him to say that fire and air are also heavy when out of their natural place, which is outside of, and above earth and water. But this does not seem in consonance with the Aristotelian use of these terms. According to Aristotle an object is heavy if its tendency is to move to the centre of the world; it is light if it moves away from the centre to the circumference. Hence earth and water are heavy, fire and air are light. The natural place of a body or element is that to which it has a tendency to move, or in which it has a tendency to rest, when left to itself. Hence a body will always move to its natural place when away from it and under no restriction; and its heaviness or lightness does not change with its position.

To continue, the sphere moves in a circle, the most perfect of all motions, having neither beginning nor end. It is more perfect than all bodies, and the knowledge of God is not hidden from it as it is hidden from us. Whatever moves in a circle must move around a body at rest; for if it moves around another moving body, this second body must have another body around which it moves, and this third body another, and so on ad infinitum, which is impossible. Hence the sphere moves around a body at rest. This is the earth.

The four elements of the sublunar world are, fire, air, water, earth. In their purity these elements have neither color nor taste, nor odor nor any other sensible property. For the elements are simple bodies, whereas the sensible qualities are the result of the composition of the elements. If air had color, we should see it as we see all colored things; and all other things would appear to us in the color of air, as is the case when we look through a colored glass. The same argument applies to water.

The elements change into each other. We see water changing under the effect of heat into vapor, and the vapor condenses again under the influence of cold and changes back to water, namely, rain. Air changes into fire when flint strikes iron. Fire cannot exist here unless it has something to take hold of; otherwise it changes into air. Earth and water change into each other very slowly, because earth is hard to change.