In the context of scholastic teaching that man is composed of body and soul, the question arises how the relationship between these two elements is to be conceived. (Although modern nonscholastic authors rarely use the term soul, they do speak of the mind-body problem, and in so doing ask essentially the same question in a less philosophical way.) The answer can be investigated generally, as applied to all species of living organisms, or it can be investigated only in relation to humanity, where it raises particularly difficult problems. Man's soul being spiritual in nature, how can such a spiritual principle be related to the matter of the human body? The disproportion between matter and spirit seems so great that it is difficult to conceive how both can be joined in man to form an essential unity.
Greek Thought. As long as greek philosophy considered only the material cause, as Aristotle noted, no major difficulty of this type arose. With the discovery of a spiritual dimension to reality, as in Plato's world of ideas, however, the problem immediately came into focus: how can something spiritual, characterized as it is by its independence from matter, be essentially bound to something material? Such a union seems contrary to the very nature of spirit. Influenced by this line of thought, plato considered the union to be a punishment for some sin committed by the soul in a former life. The relation of the soul to the body, in his view, was that of a prisoner to his prison (Phaedrus 250; Phaedo 80–83). In other texts, Plato compared the relation to that between a ship and the pilot, insofar as the soul moves and directs the body as a pilot does a ship—a relationship that remained somewhat extrinsic and accidental.
aristotle criticized this teaching of his master as inconsistent with the facts. Man is one substantial reality, not an accidental union of two different substances. Yet how can he be one substance, if two such different elements as a material body and a spiritual soul are found in him? Aristotle saw the solution in his doctrine of hylomorphism. He defined the soul as the first act of a physical organic body (Anim. 412a 20–28). Unfortunately, this cryptic definition seemed to imply a contradiction, because a physical organic body, as something determined, was already conceived as in act, and thus it was hard to see how the soul could be its "first" act. The difficulty, it turns out, is largely terminological; an adequate explanation of the Aristotelian formula can be given, although it is not easy to comprehend (see soul; entelechy). Possibly because of its concise and somewhat elliptic formulation, it has been regarded by many as not giving a satisfactory and adequate solution to the problem.
Thomistic Explanation. St. thomas aquinas, and most scholastic philosophers, took over the Aristotelian formula and used it to derive a more accurate conception. (1) The basic reality to account for, as Aquinas saw it, is the essential unity of man. This unity is clearly demonstrated by the fact that the same concrete man who is given to one's phenomenological experience in his bodily presence is also a person who thinks. The spiritual activity of thinking and the material givenness of the body are both manifestations of one and the same human reality. (2) Again, the transcendence of the spirit over material reality is manifested by the immateriality of thinking; this means that the soul, having an activity that is intrinsically independent of material conditions, cannot have a mode of being inferior to its mode of acting. In other words, it must be essentially independent of matter. (3) On the other hand, man is really material, and this not only accidentally: the body belongs essentially to his nature. How can one reconcile all three seemingly contradictory, but equally certain, data?
Soul-Body Union. Taking into account all three aspects, St. Thomas proposed a precise and ingenious solution. He refused to admit a contradiction between the spirituality of the soul and its union with a material body. This union, he argued, need not be understood as implying an essential dependence on matter. The soul, as spiritual, really exists on its own account and in its own right. In other words, it is not dependent on matter in the very fact of existing. This, in turn, does not entail that the body belongs to man only accidentally. The body is a real and essential part of man's nature, but not in such a way that the soul is essentially subjected to it or ontologically dependent upon it. On the contrary, the body is dependent upon the soul and exists in virtue of the soul's existence. As Thomas puts it: "Human existence pertains to corporeal matter as receptive and as subjected to something above it; it pertains to intellectual substance as to a principle, and according to the demands of its proper nature" (C. gent. 2.68). This describes an intimate, ontological relationship between body and soul, destroying neither man's substantial unity, nor the spiritual character of his soul, nor the body as an essential part of his nature.
Solution of Difficulties. Is this, however, only a clever theoretical construction, or is it an interpretation of man that conforms to genuine human experiences? Does the human soul really enjoy the type of superiority over the body that this ontological interpretation implies? Does experience not show, on the contrary, that man's spiritual soul is dependent upon his body in many ways? Man comes into being through biological conception and birth; the very existence of his soul seems thus to be conditioned by his body. And what about fatigue, illness, and death? In all these cases is not the soul subject to the law of the body? How can one bring such arguments in harmony with the Thomistic conception of a soul that exists in its own right, in ontological independence of the body?
It may be noted that, apart from these instances of negative interplay between body and soul, innumerable instances of a positive relation between the two are equally evident in authentic human experience. The body appears as an instrument of the soul, for example, in acquiring knowledge or in executing decisions of the will; or it simply appears as an expression of the soul, e.g., in language, in gestures, in a smile or in a tear. The main thing to be noted about these experiences, however, whether they be positive or negative, is that the Thomistic explanation does not conceive these as an interplay between two realities, but rather a mutual conditioning of two constitutive principles in one reality. Thus the soul is conditioned by the body, just as the body is conditioned by the soul. Yet the fact that the body is dependent upon the soul need not entail that the soul is also dependent upon the body. If the soul really assumes the body into its own existence, as Thomists maintain, the body cannot be considered as alien to the soul. It is the soul's body, and nothing else. The whole bodily condition, with all its implications, positive and negative, is assumed by the soul as its own. The soul cannot be said to depend upon the body, but it can be said to have assumed as its own a bodily condition. The soul does not participate in the existence of the body, but the body is assumed in the existence of the soul. Thus, although body and soul really coincide in man's substantial unity, and in a total mutual conditioning, there is a one-way dependence in the strict sense of the word, namely, that of the body upon the soul.
This delicate, subtle, and finely balanced conception of the soul-body structure gives due account of the concrete human situation, which, however materially conditioned, is marked by the absolute primacy of the spirit and of spiritual values. It is also in accord with the image of man that is presented in divine revelation.
Other Explanations. The value of this particular interpretation of the soul-body relationship may be confirmed by a brief comparison with alternative solutions.
Extreme monistic solutions, such as those reducing man to mere spirit or not taking the reality of the body seriously (e.g., platonism), or those reducing man to matter alone, considering the soul to be a manifestation of matter (e.g., materialism), do not explain the real man as given in experience. Nor does an exaggerated du alism, such as that of descartes, account for the subtle complexity and unity of man as manifested in personal and intersubjective experiences.
Again, man cut as it were in two parts—the phenomenal and the noumenal, as kant presents him—does not furnish an adequate explanation. Similarly, the positivist approach to the question reduces the delicate and complex ontological problem to a psychophysical parallelism in which the spiritual dimension of man disappears, to be replaced by a superfluous and meaningless epiphenomenon of physiological processes.
A newer and sounder conception of man's duality has been proposed in phenomenology, particularly by M. merleau-ponty and by Gabriel Marcel (see existen tialism, 4). Though thinking in very different categories, confining themselves more to phenomenological description than to ontological analysis, these thinkers have rediscovered the intimate, indissoluble union of body and mind in their conception of man as esprit incarné. Marcel concentrates on the question, "Am I body or do I have a body?" and, distinguishing between the corps objet and the corps sujet, affords new evidence for a conception of man akin to that of traditional scholasticism. Though the deeper ontological view is lacking in such phenomenological approaches, they represent a great progress over positivist conceptions and can lead to a fuller understanding of man in terms of the soul-body relationship.
See Also: soul, human; immortality; man, 3, 4.
Bibliography: n. a. luyten, "The Significance of the Body in a Thomistic Anthropology," Philosophy Today 7 (1963) 175–193; "Das Leib-Seele Problem in philosophischer Sicht," Geist und Leib in der menschlichen Existenz (Naturwissenschaft und Theologie 4; Munich 1961) 150–214. g. siewerth, Der Mensch und sein Leib (Einsiedeln 1953).
[n. a. luyten]
"Soul-Body Relationship." New Catholic Encyclopedia. . Encyclopedia.com. (December 12, 2018). https://www.encyclopedia.com/religion/encyclopedias-almanacs-transcripts-and-maps/soul-body-relationship
"Soul-Body Relationship." New Catholic Encyclopedia. . Retrieved December 12, 2018 from Encyclopedia.com: https://www.encyclopedia.com/religion/encyclopedias-almanacs-transcripts-and-maps/soul-body-relationship