The coloured plates were due probably to subjective optical sensations simultaneously excited, which were made to fit in (with or without an effort of voluntary attention) with the image of the book under the form of illustrations.

But this stage of coherency did not satisfy the mind, which, still partly confused by the incongruity of coloured plates in a philosophic work, looked for a closer connection.

The image of Hamlet was naturally suggested in connection with pessimism.

The effort to discover a meaning in the pictures led to the fusion of this image with one of the subjective spectra, and in this way the idea of a Hamlet frontispiece probably arose.
The whole process of dream-construction is clearly illustrated in a curious dream recorded by Professor Wundt.[98] Before the house is a funeral procession: it is the burial of a friend, who has in reality been dead for some time past.

The wife of the deceased bids him and an acquaintance who happens to be with him go to the other side of the street and join the procession.