of the extension of the wax, a mode which is really distinct, by a minor real distinction, from this extension which is its immediate subject.(267) Hence we conclude that there are accidental modes, or modal accidents, really distinct from the subjects in which they inhere. 69. DISTINCTION BETWEEN SUBSTANCE AND ITS “PROPER” ACCIDENTS. UNITY OF THE CONCRETE BEING.—Turning next to the distinction between absolute accidents and substance, we have seen already that separable absolute accidents such as acquired habits of mind and certain sensible qualities and energies of bodies are really distinct from their subjects. Absolute accidents which are _naturally inseparable_ from their subjects—such as external quantity or spatial extension or volume is in regard to the corporeal substance—are also really distinct from their subjects; though we cannot know by reason alone whether or how far such accidents are _absolutely separable_ from these subjects: from Christian Revelation we know that extension at least is separable from the substance of a body, and with extension all the other corporeal accidents which inhere immediately in extension.(268) But a special difficulty arises in regard to the nature of the distinction between a substance and its _proper_ accidents,(269) _i.e._ those which have such an adequate and necessary ground in the essence of the substance that the latter cannot exist without them: accidents which are simultaneous with the substance and proceed necessarily from it, such as the internal quantity of a corporeal substance, or the intellectual and appetitive powers or faculties of a spiritual substance. The medieval scholastic philosophers were by no means unanimous as to the nature of this distinction. Their discussion of the question centres mainly around the distinction between the spiritual human soul and its spiritual faculties, intellect and will, and between these faculties themselves. It is instructive—as throwing additional light on what they understood by a real distinction—to find that while Thomists generally have held that the distinction here in question is a real distinction, many other scholastics have held that it is only a virtual distinction, while Scotists have generally taught that it is a formal distinction (35-39).