Three tendencies can be observed in the estimation of dreams. Many philosophers have given currency to one of these tendencies, one which at the same time preserves something of the dream's former over-valuation. The foundation of dream life is for them a peculiar state of psychical activity, which they even celebrate as elevation to some higher state. Schubert, for instance, claims: "The dream is the liberation of the spirit from the pressure of external nature, a detachment of the soul from the fetters of matter." Not all go so far as this, but many maintain that dreams have their origin in real spiritual excitations, and are the outward manifestations of spiritual powers whose free movements have been hampered during the day ("Dream Phantasies," Scherner, Volkelt). A large number of observers acknowledge that dream life is capable of extraordinary achievements--at any rate, in certain fields ("Memory"). In striking contradiction with this the majority of medical writers hardly admit that the dream is a psychical phenomenon at all. According to them dreams are provoked and initiated exclusively by stimuli proceeding from the senses or the body, which either reach the sleeper from without or are accidental disturbances of his internal organs. The dream has no greater claim to meaning and importance than the sound called forth by the ten fingers of a person quite unacquainted with music running his fingers over the keys of an instrument. The dream is to be regarded, says Binz, "as a physical process always useless, frequently morbid." All the peculiarities of dream life are explicable as the incoherent effort, due to some physiological stimulus, of certain organs, or of the cortical elements of a brain otherwise asleep. But slightly affected by scientific opinion and untroubled as to the origin of dreams, the popular view holds firmly to the belief that dreams really have got a meaning, in some way they do foretell the future, whilst the meaning can be unravelled in some way or other from its oft bizarre and enigmatical content. The reading of dreams consists in replacing the events of the dream, so far as remembered, by other events. This is done either scene by scene, _according to some rigid key_, or the dream as a whole is replaced by something else of which it was a _symbol_. Serious-minded persons laugh at these efforts--"Dreams are but sea-foam!"