The elements of our consciousness, as the foregoing discussion has taught us, stand in general combinations with each other. Even where objective impressions lack steady combinations, we are accustomed to construct such by means of subjective sensations and feelings. The single beats of a row on the metronome are as such isolated, but we combine them into a rhythmical whole by means of our feelings of strain and relaxation, and by means of weak accompanying muscle-sensations. We have seen that in this way the different ideational compounds, the complex feelings, the emotions, and the volitional processes are all resultants of the psychical processes of combination. Now, how are these combinations constituted, and what laws are they subject to? Psychologists generally have called them "Associations," since the English philosophy of the eighteenth century turned its attention to the importance of this process of combination. The opinion has often been expressed that this one concept is sufficient to include under it all psychical processes of combination. We shall soon see, however, that thereby a very important and characteristic difference is left out of account. We shall choose this difference, since it certainly influences all processes of consciousness, as our chief principle in a division of these combinations. This distinctive characteristic consists in the fact that one set of psychical combinations acts of its own accord, i.e. without the accompaniment of those feelings of activity which we learnt were constituent parts of the processes of apperception and volition; whereas another set is closely connected with these activities. At the same time, further distinctive characteristics in the combination processes run parallel to this one. Let us therefore call only those generally passive combination processes associations, and the active ones apperceptive combinations, or for shortness apperceptions. If we limit in this way the concept "association" in contra-distinction to the ordinary use of the term, still we must enlarge it considerably on the other side, if we wish to do justice to all the combinations of this sort that really exist. The old theory of association was founded exclusively on the observation of the memory-processes. With such a process we are accustomed to take note, first of all, merely of the ideational compounds of consciousness, and secondly, the ideas in such a schematic memory-process are arranged regularly in a temporal succession; for example, an outward impression acts first of all upon consciousness, and then we remember something previous that was similar to this impression, or stood in relation to it. Now these memory-processes, as a closer inspection will show, make up a remarkably small part of our associations. They are in fact of much less importance than many other forms. As soon as we compare this form with other forms, we recognise at once that it is merely a secondary form.