In this way, though the dream-fancy sets at nought the particular relations of our experience, it respects the general and constant relations.

How are we to account for this?
It is said by certain philosophers that this superposition of the relations of space, time, causation, etc., on the products of our dream-fancy is due to the fact that all experience arises by a synthesis of mental forms with the chaotic matter of sense-impressions.

These philosophers allow, however, that all particular connections are determined by experience.

Accordingly, what we have to do here is to inquire how far this scientific method of explaining mental connections by facts of experience will carry us.

In other words, we have to ask what light can be thrown on these tendencies of dream-imagination by ascertained psychological laws, and more particularly by what are known as the laws of association.
These laws tell us that of two mental phenomena which occur together, each will tend to recall the other whenever it happens to be revived.