However popular this theory of somatic dream stimuli may have become, and however seductive it may seem, it is nevertheless easy to show the weak point in it. Every somatic dream stimulus which provokes the psychic apparatus to interpretation through the formation of illusions, is capable of giving rise to an incalculable number of such attempts at interpretation; it can thus attain representation in the dream content by means of an extraordinary number of different ideas. But the theory of Strümpell and Wundt is incapable of instancing any motive which has control over the relation between the external stimulus and the dream idea which has been selected to interpret it, and therefore of explaining the “peculiar choice” which the stimuli “often enough make in the course of their reproductive activity” (Lipps, _Grundtatsachen des Seelenlebens_, p. 170). Other objections may be directed against the fundamental assumption of the whole theory of illusions—the assumption that during sleep the mind is not in a condition to recognise the real nature of the objective sensory stimuli. The old physiologist Burdach[8] proves to us that the mind is quite capable even during sleep of interpreting correctly the sensory impressions which reach it, and of reacting in accordance with the correct interpretation. He establishes this by showing that it is possible to exempt certain impressions which seem important to the individuals, from the neglect of sleeping (nurse and child), and that one is more surely awakened by one’s own name than by an indifferent auditory impression, all of which presupposes, of course, that the mind distinguishes among sensations, even in sleep (Chapter I., p. 41). Burdach infers from these observations that it is not an incapability of interpreting sensory stimuli in the sleeping state which must be assumed, but a lack of interest in them. The same arguments which Burdach used in 1830, later reappear unchanged in the works of Lipps in the year 1883, where they are employed for the purpose of attacking the theory of somatic stimuli. According to this the mind seems to be like the sleeper in the anecdote, who, upon being asked, “Are you asleep?” answers “No,” and upon being again addressed with the words, “Then lend me ten florins,” takes refuge in the excuse: “I am asleep.”