On September 14, 1952, Pope Pius XII gave an address to the First International Congress on the Histopathology of the Nervous System. On that occasion, the Holy Father discussed the Principle of Totality at length and in the contrasting terms spelled out in this question. The principle itself is the general notion that, since parts are ordered for the good of the whole, they may be disposed of, if necessary, for the good of the whole. The application to a human person is that “parts” (i.e., organs, digits, etc.) may be mutilated, severed, removed, or otherwise debilitated if, by so doing, one benefits the person. For instance, in the case of a cancerous organ which cannot otherwise be treated than by removal, it would be morally permissible to remove the organ (thus sacrificing a “part”) in order to save the life of the man who would otherwise be in serious danger of the cancer becoming systemic. In the Holy Father’s own words, “by virtue of the principle of totality, by virtue of his right to use the services of his organism as a whole, the patient can allow individual parts to be destroyed or mutilated when and to the extent necessary for the good of his being as a whole. He may do so to ensure his being’s existence and to avoid or, naturally, to repair serious and lasting damage which cannot otherwise be avoided or repaired.” The Holy Father articulates the reasoning behind this: “Each of the members, for example, the hand, the foot, the heart, the eye, is an integral part destined by all its being to be inserted in the whole organism. Outside the organism it has not, by its very nature, any sense, any finality. It is wholly absorbed by the totality of the organism to which it is attached.”
In the italicized sentence, the Holy Father establishes the criteria by which the principle is said not to apply to an organism of a purely moral character. A kidney, a finger, or an eyeball has no finality in itself. Each is merely ordered for the good of the whole man. But such is not the case with human persons considered as “parts” of a larger moral whole. Indeed, the case of a moral organism (such as the state, or any other society of men coming together for a common end) “is an entirely different story.” Deliberately shooting an innocent man in order to preserve the good of the state would not be permissible. Nor would it be permissible to engage in harmful, non-therapeutic medical research simply on the grounds that the human person is “part” of a larger “whole” (e.g., the state, or “humanity” in general).
. Pope Pius XII, “The Moral Limits of Medical Research and Treatment,” An address given September 14, 1952, http://www.papalencyclicals.net/Pius12/P12PSYCH.HTM, No. 13.
. Ibid., No. 29.
. Ibid., No. 30.