This way of speaking of the mental materials, instead of speaking of the mind's activity, is convenient; and it is quite right to do so, since it is no contradiction to say that the thoughts, etc., which the mind "apperceives" remain "associated" together.

From this explanation it is evident that the Association of Ideas also comes under the mental process of Apperception of which we have been speaking.
There is, however, another tendency of the mind in the treatment of its material, a tendency which shows us in actual operation the activity with which we have now become familiar.

When we come to look at any particular case of apperception or association we find that the process must go on from the platform which the mind's attainments have already reached.

The passing of the mental states has been likened to a stream which flows on from moment to moment with no breaks.

It is so continuous that we can never say: "I will start afresh, forget the past, and be uninfluenced by my history." However we may wish this, we can never do it; for the oncoming current of the stream is just what we speak of as ourselves, and we can not avoid bringing the memories, imaginations, expectations, disappointments, etc., up to the present.
So the effect which any new event or experience, happening for the first time, is to have upon us depends upon the way it fits into the current of these onflowing influences.