476 W. R. BOYCE GIBSON : whatever it may be, must remain one and the same through- out, i.e., the discriminative activity of attention must move within one and the same sphere of Interest. For it is only in being related to one and the same interest that the dis- criminations of attention find their meaning ; apart from this reference they are mere disconnected observations, the well-known products of inattention. Hence there must be oneness of interest, and it is this oneness of interest that gives oneness to the object of attention and hence oneness to the consciousness attending. We may say then that the Unity of Consciousness, as the fundamental experiential fact in attentive mental process consists in a continuous identity of interest or object aimed at. Summing up we may say that the conative unity with which we are concerned is a unity whose main characteristic is not the coherency of parts within a whole but the persist- ency of one conative attitude, and further that it is just this presence in attentive consciousness of a relatively abiding element of sameness which makes possible mental retentive- ness and reproduction, the factors most vitally concerned in the formation of that coherent unity of Experience which gives to Consciousness what we may call its unity of mean- ing. 1 It is an inevitable result of trying to seize and to name the fundamental facts of a science that one does the fact injustice. To name it is but to name an aspect. What the fact really is can perhaps be best stated by stating the condition it must satisfy in order to be fundamental. That condition, as I take it, is simply this: it must be that feature of the subject- matter of the science which makes the subject-matter in all its diversity amenable to scientific treatment. But this feature which saves diversity from becoming a chaos of iso- lated fragments cannot be exhaustively embodied in the term ' unity ' unless we conceive of this unity as indissolubly in- volving other aspects to which we often give other names. In the case of mental process, or indeed of any time-process, the unity, as we have attempted to define it, involves indis- solubly at least one other aspect, that of ' continuity '. It is of no use attempting to deduce the continuity of mental process from its unity, or vice-versa. The deduction can of course be made, but as it can be made either way, the making of it does not prove the primacy of either factor. In precisely the same way the principle of virtual velocities may be de- duced from the principle of least action and the principle of 1 Cf. Stout's Manual of Psychology, bk. i., oh. ii.
