The majority of professing Christians today unconsciously hold to a form of substance dualism. Few of them are familiar with the term or the historic occasion(s) of its ascension. Fewer still are aware that the rejection of the doctrine has rich historic precedent within the Church. According to the doctrine, mind and body constitute two totally different metaphysical substances. The modern embodiment of the doctrine finds its roots in the work of the French philosopher Rene Descartes, who (re)popularized the doctrine and it has gained predominance among contemporary Christians.
Neoplatonistic philosophical anthropology came to teach something very similar. It was Aristotle who rejected what would become, at least for a time, the predominantly dualistic philosophical anthropology in the Church. For Aristotle the mind is the substantial form of the body. The two exist inseparably in a kind of organic unity. This view is closer to (but not identical with) what would eventually come to be known among analytic philosophers as property dualism. That is, there is one substance (matter), and in the case of the human person, this materiality exhibits the two properties of the mental and the physical.
This view was taken up by none other than Thomas Aquinas, who appropriately, in largely unmodified form, Aristotle’s hylemorphic anthropology. For Aquinas, the enemy was not Cartesian dualism, but the formally very similar Neoplatonistic dualism. In contemporary philosophy and theology, various forms of non-reductive physicalism, particularly in the form of emergentism, have become increasingly popular. According to the doctrine of emergentism, popularized by the so-called British emergentists in the 19th and early 20th centuries, the mental is the result of a complex system of matter behaving in a certain manner. The mind possesses causal efficacy but is nonetheless dependent upon the physical body for its subsistence.
Many Christians worry, however, that this position entails a kind of compromise with the reductive physicalism common in many of the natural sciences among non-Christians. It is important for such Christians to be aware that this an emphasis on the organic unity of mind and body not only has impressive historical pedigree within the Church, but that it is widely regarded as biblical even among highly conservative Protestant theologians. The Protestant Calvinist theologian, Louis Berkhof (1873-1957), is an important case in point.
While Berkhof acknowleedges that Scripture paints a picture of mind that is “clearly dichotomic,” he rejects as “Greek” (read: Neoplatonistic) the idea that humans consist of
“a duality, consisting of two different elements, each of which move along parallel lines but do not really unite to form a single organism. The idea of a mere parallelism between the two elements of human nature, found in Greek philosophy and also in the works of some later phlosophers, is entirely foreign to Scripture”(Berkhof). Berkhof cites Genesis 2:7, which recounts the earthy origins of man as “formed man of the dust of the ground.”
He draws attention to the particularly important point that the English translation “soul” (Job 33:4; 32:8)
“does not have the [Neoplatonist or Cartesian] meaning which we usually ascribe to it – a meaning rather foreign to the Old Testament – but denotes an animated being, and is a description of man as a whole. The very same Hebrew term, nephesh chayyah, while indicating that there are two elements in man, yet stresses the organic unity of man. And this is recognized throughout the Bible.”
He quotes Laidlaw’s “The Biblical Doctrine of Man”: “The antithesis is clearly that of lower and higher, earthly and heavenly, animal and divine. It is not so much two elements, as two factors uniting in a single and harmonious result, — ‘man became a living soul.”
So great an emphasis on the organic unity of the human person, both mind and body, is stressed in the Old Testament, that Berkhof notes that “Hebrew has no word for the body as an organism.” In other words, to refer to the “body” is not to speak of a house for an immaterial soul, but constitutes a kind of metonymical reference to the human person as a whole, both body and mind.
Berkhof, Louis. Systematic Theology. Retrieved from: http://books.biblicaltraining.org/Systematic%20Theology%20by%20Louis%20B…