Writers upon biblical psychology have for many years debated as to whether the human soul is trichotomous or dichotomous. In favor of the trichotomist view[1] it is urged that such expressions as "preserved entire, in all your parts, body, soul, and spirit,"[2] "piercing to the separation of soul and spirit,"[3] affirm a threefold division of man's nature. And it must be admitted that the settlement of the question is not altogether easy. The difficulty lies quite as much in the variety of expressions as in their indefiniteness. The older Jewish Scriptures were written at such different times and by such a variety of authors that, so far from having a common, to say nothing of a definite psychology, it is impossible to formulate even those persistent presuppositions which might be expected to underlie popular vocabularies.
The same difficulty lies to a considerable degree in some of the writings of the New Testament collection. But here the smaller number of writers, as compared with that of the older literature, makes the diversity of opinion less apparent, and to a considerable degree makes the discovery of definitions less difficult. Yet no one of these authors was a trained student of experimental science. Paul, the best educated of them all, gives little evidence of any training beyond the severely scholastic methods of the professional schools at Jerusalem. It is true he has the schoolman's accuracy in the use of terms, but he suffers also from the schoolman's lack of scientific experiment. He is not a scientist but a moralist.
If this last be true of Paul, it is truerof Jesus. He did indeed know what was in man, but his was a knowledge like that of Socrates—a practical and accurate intuition of human nature, rather than the accumulated facts of the psychologist. He has left no attempt to reduce to a system the various phenomena which the student is today taught to observe in consciousness.
