frequent than we had suspected and that it produces psychic effects even where it does not reveal itself to our consciousness. And when we have learnt that the obsessive rules of certain neurotics are nothing but measures of self-reassurance and self-punishment erected against the reenforced impulse to commit murder, we can return with fresh appreciation to our previous hypothesis that every prohibition must conceal a desire. We can then assume that this desire to murder actually exists and that the taboo as well as the moral prohibition are psychologically by no means superfluous but are, on the contrary, explained and justified through our ambivalent attitude towards the impulse to slay.
The nature of this ambivalent relation so often emphasized as fundamental, namely, that the positive underlying desire is unconscious, opens the possibility of showing further connections and explaining further problems. The psychic processes in the unconscious are not entirely identical with those known to us from our conscious psychic life, but have the benefit of certain notable liberties of which the latter are deprived. An unconscious impulse need not have originated where we find it expressed, it can spring from an entirely different place and may originally have referred to other persons and relations, but through the mechanism of displacement, it
