A reminiscence 1 the concept of the dream that was held in primitive times seems to underlie the evaluation of the dream which was current among the peoples of classical antiquity. They 2 it for granted that dreams were related to the world of the supernatural beings in 3 they believed, and that they brought inspirations from the gods and demons. Moreover, it appeared to them that dreams must 4 a special purpose in respect of the dreamer; that, as a rule, they predicted the future. The extraordinary variations in the content of dreams, and in the impressions which they produced 5 the dreamer, made it, of course, very difficult to formulate a coherent conception of 6, and necessitated manifold differentiations and group-formations, according to their value and reliability. The valuation of dreams by the individual philosophers of antiquity naturally depended on the importance which they were prepared to attribute 7 manticism in general. In 8 two works of Aristotle in which there is mention of dreams, they are already regarded as constituting a problem of psychology.