We cannot help thinking that this phenomenist denial of substance, with its consequent inevitable substantialization of accidents, is largely due to a mistaken manner of regarding the concrete existing object as a mere mechanical bundle of distinct and independent abstractions. Every aspect of it is mentally isolated from the others and held apart as an “impression,” an “idea,” etc. Then the object is supposed to be constituted by, and to consist of, a sum-total of these separate “elements,” integrated together by some sort of mental chemistry. The attempt is next made to account for our total conscious experience of reality by a number of principles or laws of what is known as “association of ideas”. And phenomenists discourse learnedly about these laws in apparent oblivion of the fact that by denying the reality of any substantial, abiding, self-identical soul, distinct from the transient conscious states of the passing moment, they have left out of account the only reality capable of “associating” any mental states, or making mental life at all intelligible. Once the soul is regarded merely as “a series of conscious states,” or a “stream of consciousness,” or a succession of “pulses of cognitive consciousness,” such elementary facts as memory, unity of consciousness, the feeling of personal identity and personal responsibility, become absolutely inexplicable.(239) Experience, therefore, does reveal to us the real existence of substances, of “things that exist in themselves,” and likewise the reality of other modes of being which have their actuality only by inhering in the substances which they affect. “A substance,” says St. Thomas, “is a thing whose nature it is to exist not in another, whereas an accident is a thing whose nature it is to exist in another.”(240) Every concrete being that falls within our experience—a man, an oak, an apple—furnishes us with the data of these two concepts: the being existing in itself, the substance; and secondly, its accidents. The former concept comprises only constitutive principles which we see to be _essential_ to that sort of being: the material, the vegetative, the sentient, the rational principle, in a man, or his soul and his body; the material principle and the formal or vital principle in an apple. The latter concept, that of accidents, comprises only those characteristics of the thing which are no doubt real, but which do not constitute the essence of the being, which can change or be absent without involving the destruction of that essence. An intellectual analysis of our experience enables us—and, as we have remarked above, it alone enables us—to distinguish between these two classes of objective concepts, the concept of the principles that are essential to the substance or being that exists in itself, and the concept of the attributes that are accidental to this being; and experience alone enables us, by studying the latter group, the accidents of the being,