As Addison remarks (Spectator 487), "There is not a more painful action of the mind than invention, yet in dreams it works with that ease and activity that we are not sensible of when the faculty is employed. For instance, I believe every one some time or other dreams that he is reading papers, books, or letters, in Which case the invention prompts so readily that the mind is imposed upon, and mistakes its own suggestions for the composition of another."

The facility of composition in sleep is more apparent than real. What we compose or read in dreams is, for the most part, matter with which we are already acquainted, and in the same form in which it occurs in the dream. Being already present in the mind, and not requiring actual composition, as would be required in building a new structure by directive, creative thought, it can be speedily dramatized by sleeping consciousness. Often we deem our dream compositions excellent; waking reason and judgment consider them mediocre, or poor. Exceptions may occur, but we are generally safe in concluding that we are capable of no greater ability when asleep than when awake.

Such conversations as we conduct in dreams proceed, of course, from ourselves, though in the dream we may not be aware of this. Thus, Dr. Johnson dreamt that he was in an argument with a man, the latter exceeding him in points of wit; on awaking, Johnson's chagrin was appeased by his realization that he had supplied the wit for both characters. In dreams all that seems of sudden suggestion is attributed to another person; we divide our personalities. Considering that the speeches of the dream images, no matter how many there may be, are supplied by the dreamer himself, it may be asked if a somniloquist actually speaks the words of each of the characters. Practically always he says the words which he believes are his own.