The visceral and emotional element in dreaming helps to explain the dreamer's moral attitude and the real significance of those criminal actions in dreams which have often been misinterpreted. Many writers on dreaming have referred, with profound concern, to the facility and prevalence of murder in dreams, sometimes as a proof of the innate wickedness of human nature made manifest in the unconstraint of sleep, sometimes as evidence of an atavistic return to the modes of feeling of our ancestors, the thin veneer of civilisation being removed during sleep. Maudsley and Mme. de Manacéïne, for example, find evidence in such dreams of a return to primitive modes of feeling. Clarke speaks of 'the entire absence of the moral sense' from dreams.[95] Professor Näcke, who has given much attention to the phenomena of dreaming, writes in a private letter: 'What I am amazed at, having perceived it in myself, is the little known fact that a person's character becomes _worse_ in dreaming. Not only the most secret thoughts, wishes, and aspirations become clear, but also qualities which have never been observed before, as, for instance, that one becomes a murderer, an adulterer, etc.' Freud, especially, has elaborated this aspect of dreams as representing the fulfilment of the dreamer's most secret desires.[96] It may well be that there is an element of truth in the belief that in dreams we are brought back to mental conditions somewhat more closely approaching those of primitive times. It is the manifold variety and complexity of our mental representations which prevent us from responding immediately to impulse under civilised conditions, and when, by dissociation, only a few groups are present to consciousness, the inhibition on violent action tends to be removed. If, therefore, we are more violent, more immoral, more criminal, in our dreams than in waking life, this is by no means necessarily to be regarded as a revelation of our real nature, but is merely an inevitable result of the mental dissociation which prevents many important groups of mental representations from finding their way into consciousness, and at the same time brings all our mental possessions on to the same plane, so that the things we have merely thought or heard of have the same visual reality as our own actual experiences. The sleep of the real criminal, as Sante de Sanctis has shown on the basis of a wide experience, even of criminals guilty of serious acts of violence, tends to be peaceful and dreamless, and such dreams as they have are usually of a simple and innocent sort. If normal people often dream of crime, it is because they are more sensitive and imaginative, and because sleeping consciousness is strained to the utmost to invent a phantasmal tragedy adequate to account for the waves of emotion that beset it.[97]