Reference has been made in the newspapers recently to questions that are being investigated by scientists, as to why criminals sleep well, while moral people with a good conscience often sleep badly. […] In the case of a highly conscientious and devout man, who has a fine moral feeling, his moral sensibility enters so deeply into his soul that he takes it with him into sleep; with the result that he sleeps badly, believing as he does that he has been guilty of many misdeeds.
A bad man, on the other hand, whose moral sensibility is very little developed, will carry with him into sleep no such pangs of conscience, — and this will mean of course at the same time that he will have, spiritually speaking, an open ear for the whisperings of Ahriman who makes evil appear good. Hence the quiet and contented sleep of the criminal!
Source: Rudolf Steiner – GA 218 – Man’s Life on Earth and in the Spiritual Worlds: Lecture IV – London, 12th November, 1922
Translated by George and Mary Adams