Now, the nature of a thing is its working essence. And the essence of a thing is that which constitutes it and makes it what it is. Essence regarded as the source of operations is called nature; thus we are justified in our description of nature as “working essence.” To illustrate: the essence of man (physically considered) is his body and soul; these are the elements which constitute a human being, and make him what he is in his fundamental actuality. But the nature of a man is the essence looked at as the source and font of human operations. So we say that it is according to man’s nature that he feels and sees and thinks and wills. Man’s essence works that way. That is his mode of operation. That is his nature.
When we say that the nature of man is rational we use the term in its original Latin meaning, not in its current meaning of “conscious” or “normal.” A rational nature means a nature fundamentally equipped for understanding and freely choosing. We do not say that a being of rational nature can think or will at any instant; no, we say that such a being is fundamentally equipped for thinking and willing, even through some obstacle should prevent the exercise of these activities. Thus a baby, even a baby yet unborn; a madman; a man unconscious, each of these is a being of rational nature as truly as is the alert, mature, and normal man who is consciously exercising his powers of thinking and willing. This is a point of boundless importance for many reasons which lie outside the scope of this present study. But one of these reasons is of such vital character that it must be allowed to obtrude itself even here; we shall pause upon it for a brief paragraph.
One great reason for stressing the true meaning of the phrase “rational nature” lies in the fact that current usage makes the word “rational” practically synonymous with the word “conscious,” or the word “lucid,” or the word “normal.” Thus we speak of one recovered from the stress of high emotion, or of one who has emerged from delirium or coma, or of one who has achieved normality after a temporary lapse into insanity, as one who “is quite rational again.” This is a sad, nay a disastrous use of the word. For it has in it the suggestion, – which grew up and grew strong together with the materialistic and pagan view of things which we call “modern” and sometimes “scientific,” – that one who is not “rational” (that is, one who is not in adequate and active awareness and management of himself) is something less than human. Especially is this so with reference to the unborn child, the insane, the more benighted sort of criminal, the senile, the immature, – the “unfit,” in a word. And out of this evil sense of the term “rational” has come, in a measure far greater than most of us realize, our easy tolerance, our sober acceptance, of “scientific” discussions and justifications of abortion, of forced sterilization, of euthanasia or “mercy killing.” No one would listen for a moment to the proposal, however sober and “scientific,” that we should murder or mutilate a great number of perfectly normal men. But many of us will listen patiently, perhaps with half-assent, to the proposal that the abnormal, the subnormal, or the outworn should be eased gently out of life or mutilated and made impotent to propagate. It is, in large measure, our false grasp of the word “rational” that prevents us from seeing that the one proposal is precisely the same as the other. Each is a proposal to maim or murder human beings, every one of whom is a being of rational nature.
Here we recall an important distinction. A being fundamentally equipped for an operation is said to possess in actu primo the perfection which that operation indicates or bestows. A being that exercises the operation is said to possess its perfection in actu secundo. Literally, the Latin phrases mean, respectively, “in first actuality” and “in second actuality”; we may, however, translate them freely as “in basic fact” and “in actual exercise.” Thus a baby is a thinking and a walking being in actu primo or in basic fact, because it is fundamentally equipped for the operations of thinking and walking, even though lack of experience and of development balks the actual exercise of these operations. After a time, the child will both think and walk, and, in exercising these operations, it will be a thinking and a walking being in actu secundo or in actual exercise. It will think and walk in the second place, given the existence of the basic equipment for thinking and walking in the first place. Now, the point here to remember is that every rational creature is rational by reason of the fact that it possesses in actu primo the powers of understanding and free choice.
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The above is from him. Please do not be overwhelmed by the text length. It is actually quite short and only fits less than 2 pages in his original book. It does seem long because the default view of message posts is vertical.
