Page:Mind (Old Series) Volume 12.djvu/39

26 PEOF. W. JAMES I To clear up our thoughts about this latter mystery, let us take the case of an actual line of light, none of whose parts are ideal. The feeling of the line is produced, as we know, when a multitude of retinal points are excited together, each of which when excited separately would give rise to one of the feelings called local-signs. Each of these signs is the feeling of a small space. From their simultaneous arousal we might well suppose a feeling of larger space to result. But why should it be necessary that in this larger spaciousness each local-sign (or whatever other feeling now in the aggre- gate excitement corresponds to the local-sign) should appear out- and along-side of its neighbour in a strictly determinate position which it never abandons ? Why should the sign a be always at one end of the line, z at the other, and m in the middle ? For though the line be a unitary streak of light, its several constituent points can nevertheless break out from it, and become alive, each for itself, under the selective eye of attention. The uncritical reader, giving his first careless glance at the subject, will say that there is no mystery in this, and that " of course " local-signs must appear alongside of each other, each in its own place ; there is no other way possible. But the more philosophic student, whose business it is to discover difficulties quite as much as to get rid of them, will reflect that it is conceivable that the partial factors might fuse into a larger space, within whose bulk each should be discriminated just as we discriminate a single voice in a chorus, not by its position but rather by its quality. 1 He will wonder why, after combining into the line, the points can become severally alive again : the separate puffs of a siren no longer strike the ear after they have fused into a certain pitch of sound. He will recall the fact that when, after looking at things with one eye closed, we double the number of retinal points affected by opening the other eye, the new retinal sensations do not as a rule appear alongside of the old ones and additional to them, but merely make the old ones seem larger and nearer. Why should the affection of new points on the same retina have so different a result ? In fact he will see no sort of logical connexion between (1) the original separate local-signs, (2) the line as a unit, (3) the line with the points dis- criminated in it, and (4) the various nerve-processes which subserve all these different things. He will suspect our 1 Remember the definition of local-sign (p. 21) as a mere "intensive' quality of feeling, which, only in combination with other feelings, produces a feeling of space-relation.