Sympathetic resonance. – All stronger moods bring with them a sympathetic resonance on the part of related sensations and moods: they as it were root up the memory. Something in us is provoked to recollection and becomes aware of similar states and their origins. Thus there come to be constructed habitual rapid connections between feelings and thoughts which, if they succeed one another with lightning speed, are in the end no longer experienced as complexes but as unities. It is in this sense that one speaks of the moral feelings, of the religious feelings, as though these were simple unities: in truth, however, they are rivers with a hundred tributaries and sources. Here too, as so often, the unity of the word is no guarantee of the unity of the thing.
Human, All Too Human, book 1, paragraph 14