of added secondary forms, i.e. accidental forms. Such composition cannot be understood unless being is really received in an essence distinct from it. Besides the absolute accidents there is also the relative accident, relation. Although by reason of its own character relation does not signify anything inhering in another, it nevertheless often has a cause in things, and hence a real entity distinct from the subject. A spiritual creature is wholly simple in its essence. Yet there is still a twofold composition in the spiritual creature, namely, that of the essence with being, and that of the substance with accidents. However, the corporeal creature is composed of act and potency even in its very essence. These act and potency in the order of essence are designated by the names form and matter respectively. Cosmology Neither the matter nor the form have being of themselves, nor are they produced or corrupted of themselves, nor are they included in any category otherwise than reductively, as substantial principles. Although extension in quantitative parts follows upon a corporeal nature, nevertheless it is not the same for a body to be a substance and for it to be quantified. For of itself substance is indivisible, not indeed as a point is indivisible, but as that which falls outside the order of dimensions is indivisible. But quantity, which gives the substance extension, really differs from the substance and is truly an accident. The principle of individuation, i.e., of numerical distinction of one individual from another with the same specific nature, is matter designated by quantity. Thus in pure spirits there cannot be more than one individual in the same specific nature. By virtue of a body's quantity itself, the body is circumscriptively in a place, and in one place alone circumscriptively, no matter what power might be brought to bear. Bodies are divided into two groups; for some are living and others are devoid of life. In the case of the living things, in order that there be in the same subject an essentially moving part and an essentially moved part, the substantial form, which is designated by the name soul, requires an organic disposition, i.e. heterogeneous parts. Psychology Souls in the vegetative and sensitive orders cannot subsist of themselves, nor are they produced of themselves. Rather, they are no more than principles whereby the living thing exists and lives; and since they are wholly dependent