SOUL, in the language of spiritualistic philosophers, covers the whole region of mind, and is generally conceived of as a naturally imperishable entity, in relation with the body, but definable, for the most part, only in terms of the complete negation of mate rial attributes. With this the popular conception in the main coincides, though it is less labored and cousiderablyt less negative. In its original signification the word appears to have stood for the principle of life both in men and in animals. The modes of conceiving it were various: it was sometimes regarded as the mere harmony of the bodily functions, and sometimes as a distinct entity of highly ethereal nature, and gener ally supposed to be seated in, or connected with, the blood; but no essential distinction was made between the soul of man and the soul of brutes. Very soon, however, the manifest superiority of man to the lower creation suggested difficulties, which were increased as tlic thought of an after-life, in a different sense from transmigration, was gradually developed. And in man, the constant war among his members. the oppo •ition of passion and reason, as it began to be observed with the growing habit of intro spection, called for some explanation which should apply to humanity only. To meet all such difficulties, a " trichotomy,' or three-fold division of the human constitution was assumed, according to which a naturally immortal and rational element was sup posed to make pert of man, besides the animal soul (always variously conceived) which he shared with the brutes. Between the two distinct elements—the animal and the rational soul—the various mental energies were differently apportioned by different thinkers, according as those energies were thought more or less noble and divine. Without going back upon obscure traditions regarding the beliefs of the early peoples, Plato's views may be cited as amounting to a trichotomy, and in Aristotle there is the distinct mention of a noctic principle in man by the side of the animal soul. Later
Greek schools put forward a similar view; and Philo, the forerunner of the Neoplaton ists, even spoke of the soul of the soul. Lucretius has the same curious expression, to which corresponds the distinction of Roman writers in general between animus and the animal soul, anima. The earliest Christian writings occasionally distinguish body, soul, and spirit (pneuma). Such a threefold division was unfamiliar to the Jewish mind, which appears to have rested in a kind of dualism, and was removed even from this common Greek philosOphical expression, pueuma being the word employed by Stoic dualists to describe the fine ethereal nature of the material soul. It is hard to say -1diether a thoroughgoing trichotomy was meant by. the Christian writers, or whether the soul was not merged in either of the extreme elements—the coarse material body, or (as commonly Conceived) the finely attenuated but still material spirit. Till about the 4th c., the language of trichotomy prevailed in the Christian writings, but thenceforth the doctrine became suspect, having been specially appropriated by certain heretical sects, and soul and spirit came to be identified in substance, and distinguished only in function. Aquinas, and, later, Calvin, pronounced in favor of the dualistic rendering, after which modern popular expression has been molded, chiefly through the predomi nant influence of spiritualism since the time of Descartes. This gives prominence to the word soul over spirit, except in religious and purely metaphysical aspects. 'The succes sors of Descartes have followed him in calling the single soul at once both rational and sensitive; but in rejecting, almost without exception, his description of the lower ani mals as mere mechanical automata, they have ignored, without au attempt to explain, the real difficulty that lie sought to get rid of, and that the trichotomy sought to meet. The ancient doctrine has been revived in various shapes by Paracelsus, Van Helmont, the anatomist Willis, De Maistre, and others.