It follows from this that the mind will be habitually disposed to form the corresponding mental images, and to interpret impressions by help of these.

The range of artistic suggestion depends on this.

A clever draughtsman can indicate a face by a few rough touches, and this is due to the fact that the spectator's mind is so familiarized, through recurring experience and special interest, with the object, that it is ready to construct the requisite mental image at the slightest external suggestion.

And hence the risk of hasty and illusory interpretation.
These observations naturally conduct us to the consideration of the second great group of sense-illusions, which I have marked off as active illusions, where the action of a pre-existing intellectual disposition becomes much more clearly marked, and assumes the form of a free imaginative transformation of reality..