It was natural that this should be so.

Both in the history of the race and in that of the individual, we find that the attention is seized first by material things, and that it is long before a clear conception of the mind and of its knowledge is arrived at.

Observation precedes reflection.

When we come to think definitely about the mind, we are all apt to make use of notions which we have derived from our experience of external things.

The very words we use to denote mental operations are in many instances taken from this outer realm.