Coming now to subjective conditions we find that the detection of an element in a complex is aided by a previous familiarity with this apart from its present concomitants. Thus the singling out of the partial tones of a clang is greatly aided by the circumstance that these occur and so are known apart from the ground-tone and thus are more readily picked out and recognised.[96] Again, the separate detection of a presentative element is aided by special interest in the particular material. A fine ear for clang-effect or timbre can more readily fix its attention on this.
[96] According to Helmholtz this previous familiarity with the elements of a composite whole when it gives rise to a vivid expectation may produce an illusory analysis, as when certain opticians affirmed that they could detect the supposed constituents of green, blue, and yellow, in that color. See Physiol. Optik, p. 273.
Such special interest works mainly through what is known as practice. What we are accustomed to note, and exercised in picking out from its surroundings, we are able to detect readily. This effect of practice in facilitating analysis or abstract attention to this and that constituent of a presentation-complex is abundantly shown throughout the whole domain of recent experimental inquiry into the nature and relations of sensation.
Of course all such analytical separation of presentative constituents is limited by certain conditions in our sensibility. Thus the limits of local discrimination obviously confine the range of isolating attention to local detail in our tactual and visual presentations. Since too such isolation is differentiation, i. e. the singling out of some trait or feature different in quality or intensity from surrounding features, it follows that our abstraction is in all cases limited by our discrimination. We cannot separately fixate a local detail of color if this is not qualitatively distinguishable from its surroundings, nor a local detail of form if this is not distinguishable in luminous intensity from its entourage. Similarly with respect to the difficult analysis of complex tone-presentations or clangs and taste-presentations, as the mixed flavors of a dish.
b) Synthesis: Conscious Relating.—In the second place all thought is integrating or combining, or, as it is commonly expressed, a process of Synthesis. In thinking we never merely isolate or abstract. We analytically resolve the presentative complexes of our concrete experience only in order to establish certain relations among them. The most appropriate term for all such conscious relating or discernment of relation is Comparison.
All our sensational or presentative material is given in certain relations or connections, including the relation of coexistence, or coinherence in a substance, of the several qualities of a thing. Thus the several parts of an extended body stand in certain spatial relations one to another, one part being situated to the right of the other, and the object as a whole being above and behind another object, and so forth. To these space-relations must be added the time-relations of all events, such as the movements of objects, their changes of form, and so forth. Lastly with these 'external' relations are given the so-called 'internal' relations of difference and likeness. The colors, forms, and so forth that present themselves from time to time exhibit a large variety of such relations.
As long as we perceive or imagine the concrete object as such we have only a vague 'implicit' knowledge of these relations. Thus a child in looking at a house sees implicitly the chimney in a definite spatial relation to the mass of the building, but the clear explicit grasp of the relation is a subsequent process going beyond perception and involving a rudiment of what we mark off as thought. In like manner when in recollection we recall a sequence of experiences, we may implicitly recognise one as following another; yet it is only by a process of thought that we explicitly single out this relation for special consideration.
The same holds good with regard to the all-comprehensive relations of dissimilarity and similarity. A child in perceiving a particular object, say a tree, differentiates it from surrounding objects, other trees, the background of the sky, etc., and in recognising a familiar object as his toy, or as an orange, he assimilates it to previous like presentations. But in these cases the consciousness of difference and likeness is implicit only. It is some way from this implicit or unconscious discrimination and assimilation to comparison proper, issuing in a clear or explicit consciousness of a relation of likeness or of unlikeness.
It follows from this that thought grows by insensible gradations out of the lower intellective operations. The perception of objects in space, and still more, the recollection of events in time, is itself an incipient subconscious stage of the thought process, i. e. grasp of relations. Hence our demarcations of the spheres of sense and thought, of concrete or pictorial and abstract representations, are not to be taken absolutely. The germ of thought is present throughout, yet as we shall see presently it is a considerable step from the implicit to the explicit seizing of these relations.[97]
[97] Cf. Lotze, Mikrokosmus, English translation, i. p. 655; Ward, article "Psychology," Encycl. Britannica, p. 75.