This incipient activity stands to overt action much as an image stands to a sensation. But such ‘imaginal’ activity is, by its very nature, extraordinarily hard to detect or to experiment upon. Psychology has only dealt with fringes of the mind hitherto and the most accessible fringe is on the side of sensation. We have therefore to build up our conjectures as to the rest of mental happenings by analogy with the perhaps not entirely representative specimens which sensation supplies. This limitation has led the majority of psychologists to see in imaginal movement no more than images of the _sensations_ from muscle, joint, and tendon, which would arise if the movement were actually made. It is certain that before any action takes place a preliminary organisation must occur which ensures that the parts do not get in one another’s way. It appears to the writer that these preliminaries in his case make up part of consciousness, but there is a heavy weight of authority against him. The point is no doubt exceptionally hard to determine. In any case, whether the consciousness of activity is due to sensations and images of movements alone, or whether the outgoing part of the impulse and its preparatory organisation help to make up consciousness, there is no doubt about the importance of incipient and imaginal movement in experience. The work done by Lipps, Groos and others on _einfühlung_, or empathy, however we may prefer to restate their results, shows that when we perceive spatial or musical form we commonly accompany our perception with closely connected motor activity. We cannot leave this activity out of our account of what happens in the experiences of the arts, although we may think that those who have built upon this fact what they have put forward as a complete æsthetic—Vernon Lee, for example—have been far from clear as to what questions they were answering.