3. The existence of the unconscious, and therefore involuntary, causes is rather suspected than proved. They consist in strange associations of ideas formed at the period of puberty, whose ultimate reason eludes observation; they might be compared to certain cases of _audition colorée_, when a connection is formed between a sound and a colour, apparently fortuitous, but in reality resting on a common emotional basis. More than this, observation seems to show that, at a much earlier age, in the fifth or sixth year, there are apt to occur “unconscious genital impulses provoking associations of ideas which frequently serve, in later years, as a _substratum_ to our sentiments and volitions. Most of these associations are unstable, and remain outside the consciousness. In the degenerate they take on the impulsive and overpowering character which distinguishes their psychology; their intensity expresses the degree of consciousness which accompanies them, the recollection which is still connected with them, even the importance they assume in later existence. The existence of an unconscious sub-personality directing the conscious one manifests itself here rather than elsewhere with undeniable clearness.”[162] Footnote 162: Dallemagne, _Dégénérés et Déséquilibrés_, p. 327. 4. There remain the conscious voluntary causes which are the converse of the physical causes, representing an action from above downwards of the superior centres on the inferior centre and the organs. It is here that instinct finds itself in conflict with its most redoubtable enemy, the intense and persistent image. In predisposed subjects the creative power of the imagination works at some construction on an erotic theme, as in others it produces a mechanical invention, a work of art, a scientific discovery. Every vivid image tends to realise itself; in the present case it has the power to divert instinct from its natural channel if its motor power is stronger, and the sexual instinct has not in all men an equal stability. I do not think, however, that these causes are sufficient to explain everything, even if we take account of imitation which fixes itself in custom, and of the contagion of example. If the facts were taken in detail, omitting nothing, we should meet with more than one embarrassing complication. Thus, sexual aberrations are found in animals, though of but moderate intelligence and living quite free from constraint. Can we, considering this, throw all the blame on imagination? They are also found among primitive races: the Huns, say ancient historians, had made of unnatural love a regular institution; can we blame civilisation? Many other difficulties of this kind might be raised; but I may remind the reader that pathology is only introduced into this work by way of elucidation, and it seems to me that, in the present subject, it receives from normal psychology more light than it throws on it. CHAPTER VII.