First, as regards our knowledge of the _existence_ of substances, and the manner in which we obtain our concept of substance. We get this concept from corporeal substances, and afterwards apply it to spiritual substances; so that our knowledge of the former is “immediate” only in the relative sense of being prior to the latter, not in the sense that it is a direct intuition of the natures of corporeal substances. We have no such direct insight into their natures. But our concept of them as actually existing is also immediate in the sense that _at first_ we _spontaneously_ conceive _every_ object which comes before our consciousness _as something existing in itself_. The child apprehends each separate stimulant of its sense perception—resistance, colour, sound, etc.—as a “this ”or a “that,” _i.e._ as a separate something, existing there in itself; in other words it apprehends all realities as substances: not, of course, that the child has yet any reflex knowledge of what a substance is, but unknowingly it applies to all realities at first the concept which it undoubtedly possesses “something existing in itself”. It likewise apprehends each such reality as “one” or “undivided in itself,” and as “distinct from other things”. Such is the child’s immediate, direct, and implicit idea of substance. But if we are to believe Hume, what is true of the child remains true of the man: for the latter, too, “every perception is a substance, and every distinct part of a perception a distinct substance”.(231) Nothing, however, could be more manifestly at variance with the facts. For as reason is developed and reflective analysis proceeds, the child most undoubtedly realizes that not everything that falls within its experience has the character of “a something existing in itself and distinct from other things”. “Walking,” “talking,” and “actions” generally, it apprehends as realities,—as realities which, however, do _not_ “exist in themselves,” but in other beings, in the beings that “walk” and “talk” and “act”. And these latter beings it still apprehends as “existing in themselves,” and as thus differing from the former, which “exist not in themselves but in other things”. Thus the child comes into possession of the notion of “accident,” and of the further notion of “substance” as something which not only exists in itself (οὐσία, _ens in se subsistens_), but which is also a support or subject of accidents (ὑποκείμενον, _substans_, _substare_).(232) Nor, indeed, need the child’s reason be very highly developed in order to realize that if experience furnishes it with “beings that do not exist in themselves,” there must also be beings which do exist in themselves: that if “accidents” exist at all it would be unintelligible and self-contradictory to deny the existence of “substances”.