A fully developed dream is a complex of many distinct illusory sense-presentations: in this respect it differs from the illusions of normal waking life, which are for the most part single and isolated. And this complex of quasi-presentations appears somehow or other to fall together into one whole scene or series of events, which, though it may be very incongruous and absurdly impossible from a waking point of view, nevertheless makes a single object for the dreamer's internal vision, and has a certain degree of artistic unity. This plastic force, which selects and binds together our unconnected dream-images, has frequently been referred to as a mysterious spiritual faculty, under the name of "creative fancy." Thus Cudworth remarks, in his _Treatise concerning Eternal and Immutable Morality_: "That dreams are many times begotten by the phantastical power of the soul itself ... is evident from the orderly connection and coherence of imaginations which many times are continued in a long chain or series." One may find a good deal of mystical writing on the nature and activity of this faculty, especially in German literature. The explanation of this element of organic unity in dreams is, it may be safely said, the crux in the science of dreams. That the laws of psychology help us to understand the sequences of dream-images, we have seen. What we have now to ask is whether these laws throw any light on the orderly grouping of the elements so brought up in consciousness in the form of a connected experience.