But it takes more than the unity of a manifold "intentional life," with its inseparable complement of "sense-unities," to make a "soul." For from the individual life that "ego-subject" cannot be disjoined, which persists as an identical ego or "pole," to the particular intentions, and the "habits" growing out of these. Thus the "inter-subjective," phenomenologically reduced and concretely apprehended, is seen to be a "society" of "persons," who share a conscious life.
Phenomenological psychology can be purged of every empirical and psycho-physical element, but, being so purged, it cannot deal with "matters of fact." Any closed field may be considered as regards its "essence," its eibos, and we may disregard the fac tual side of our phenomena, and use them as "examples" merely.
We shall ignore individual souls and societies, to learn their a priori, their "possible" forms. Our thesis will be "theoretical," observing the invariable through variation, disclosing a typical realm of a priori. There will be no psychical existence whose "style" we shall not know. Psychological phenomenology must rest upon eidetic phenomenology.
The phenomenology of the perception of bodies, for example, will not be an account of actually occurring perceptions, or those which may be expected to occur, but of that invariable "struc ture," apart from which no perception of a body, single or pro longed, can be conceived. The phenomenological reduction re
veals the phenomena of actual internal experience ; the eidetic reduction, the essential forms constraining psychical existence.
Men now demand that empirical psychology shall conform to the exactness required by modern natural science. Natural science, which was once a vague, inductive empiric, owes it modern char acter to the a priori system of forms, nature as it is "con ceivable," which its separate disciplines, pure geometry, laws of motion, time, etc., have contributed. The methods of natural science and psychology are quite distinct, but the latter, like the former, can only reach "exactness" by a rationalization of the "essential." The psycho-physical has an a priori which must be learned by any complete psychology, this a priori is not phenomenologi cal, for it depends no less upon the essence of physical, or more particularly organic nature.