Systematic Theology, by Louis Berkhof - New Leaven

7:34; II Cor. 7:1; Eph. 2:3; Col. 2:5. (d) Heb. 4:12 should not be taken to mean that the
word of God, penetrating to the inner man, makes a separation between his soul and his
spirit, which would naturally imply that these two are different substances; but simply
as declaring that it brings about a separation in both between the thoughts and intents
of the heart. 10
3. THE RELATION OF BODY AND SOUL TO EACH OTHER. The exact relation of body and
soul to each other has been represented in various ways, but remains to a great extent a
mystery. The following are the most important theories relating to this point:
a. Monistic. There are theories which proceed on the assumption that body and soul
are of the same primitive substance. According to Materialism this primitive substance
is matter, and spirit is a product of matter. And according to absolute Idealism and
Spiritualism the primitive substance is spirit, and this becomes objective to itself in what
is called matter. Matter is a product of the spirit. The objection to this monistic view is
that things so different as body and soul cannot be deduced the one from the other.
b. Dualistic. Some theories proceed on the assumption that there is an essential
duality of matter and spirit, and present their mutual relations in various ways: (1)
Occasionalism. According to this theory, suggested by Cartesius, matter and spirit each
works, according to laws peculiar to itself, and these laws are so different that there is
no possibility of joint action. What appears to be such can only be accounted for on the
principle that, on the occasion of the action of the one, God by His direct agency
produces a corresponding action in the other. (2) Parallelism. Leibnitz proposed the
theory of pre-established harmony. This also rests on the assumption that there is no
direct interaction between the material and the spiritual, but does not assume that God
produces apparently joint actions by continual interference. Instead it holds that God
made the body and the soul so that the one perfectly corresponds to the other. When a
motion takes place in the body, there is a corresponding movement in the soul,
according to a law of pre-established harmony. (3) Realistic Dualism. The simple facts to
which we must always return, and which are embodied in the theory of realistic
dualism, are the following: body and soul are distinct substances, which do interact,
though their mode of interaction escapes human scrutiny and remains a mystery for us.
The union between the two may be called a union of life: the two are organically
related, the soul acting on the body and the body on the soul. Some of the actions of the
10 Cf. for a discussion of the psychology of Scripture especially, Bavinck, Bijbelsche en Religionize
Psychologie; Laidlaw, The Bible Doctrine of Man, pp. 49-138; H. Wheeler Robinson, The Christian Doctrine of
Man, pp. 4-150; Delitzsch, System of Biblical Psychology; Dickson, St. Paul’s Use of Terms Flesh and Spirit.
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