in “(1) their heuristic anticipation, (2) in the experimental techniques of their discovery, (3) in their formulations, and (4) in their verification.”102 In heuristic, classical theory looks to understand the intelligibility immanent to the data, expecting also that genuine understanding could be extended to all similar data, for the “nature to be known will be the same for all data that are not significantly different.”103 Further, concrete differences of time, place, or person, are to be ignored, and the techniques of experiment are to be applicable and repeatable for all. Consequently, the language with which intelligibility is formulated must not rely upon the vagaries of particular times or places, and thus a specialized and abstract language is required. Finally, a possible grasp of intelligibility is not verified with an isolated concrete instance but by a general and large number of instances; certainly the testimony of the wise person alone is not sufficient.
We see how the heuristic shapes conceptions of law, most obviously in the sense of a scientific law of nature: Law expresses a necessary principle based upon a grasp of the intelligibility within data, and which cannot be rationally denied. Of course, the question arises as to what allows such cognition to be moral law, as opposed to just a law of how intelligibility is anticipated. What makes law normative?104 For theory, natural law looks very much like a law of nature in its structure, for the forms of thought operate within the theoretical mode of meaning.
Theoretical Natural Law—The Default
Jacques Maritain summarizes much of the classical tradition of natural law when he writes:
I am taking it for granted that there is a human nature, and that this human nature is the same in all men. . . . [P]ossessed of a nature, or an ontological structure which is a locus of intelligible necessities, man possesses ends which necessarily correspond to his essential constitution and which are the same for all. All pianos (whatever their particular type and in whatever spot they may be) have as their end the production of musical sounds. If they do not produce these sounds, they must be tuned, or discarded as worthless. But since man is endowed with intelligence and determines his own ends, it is up to him to put himself in tune with the ends necessarily demanded by his nature.105
There is a universal and essential nature, says Maritain, with teleology necessarily linked to the ontological constitution of the human, just as for “any kind of thing existing in nature, a plant, a dog, a horse, has its own natural law, that is, the normality of its functioning, the proper way in which, by reason of its specific structure and specific ends, it should achieve fullness of being either in its growth or in its behavior.”106 Consequently, the “first basic element to be recognized in natural law, is, then, the ontological element.”107
For Maritain, and indeed for many others, all claiming the support of Aquinas, natural law obviously depends upon metaphysics of the classical type, where an essential constitution, universally and necessarily determinative of the nature and ends of every member of a species, provides the grounding by which to determine the proper function, and thus also the improper function, of an entity. Further, since natural law is written in nature in a necessary way, human knowledge of its basic principle is self-evident and the law is the “ensemble of things to do and not to do which follow therefrom in a necessary fashion.”108 Certainly it is the case that “every sort of error and deviation is possible,” that “our nature is coarse, and that innumerable accidents can corrupt our judgment,” but this shows only that “our sight is weak,” and “proves nothing against natural law, any more than a mistake in addition proves anything against arithmetic. . . .”109
Natural law requires necessity and invariance, but in a world of flux this is found only in the domain of episteme, and thus turning to the concrete human person is insufficient. Instead, natural law begins with a metaphysics of the person, with the universal, abstract, and unchanging. Heinrich Rommen puts it thus:
The idea of natural law obtains general acceptance only in the periods when metaphysics, queen of the sciences, is dominant. It recedes or suffers an eclipse, on the other hand, when being . . . and oughtness, morality and law, are separated. . . . The natural law, consequently, depends on the science of being, on metaphysics. Hence every attempt to establish the natural law must start from the fundamental relation of being and oughtness, of the real and the good. Since the establishment of the natural law further depends upon the doctrine of man’s nature, this human element has also to be studied. . . .110
Natural law depends upon a knowledge of being, of the being of the human person, and is derived from a theoretical anthropology whereby we first know what sort of beings we are, and only subsequently know what goods are proper to us, what goods we are obligated to pursue: “being and oughtness must in the final analysis coincide.”111
Ontological and Epistemological Realism
By metaphysics, Rommen means the Aristotelian-Thomistic synthesis, committed to both ontological and epistemological realism, since natural law is “possible only on the basis of a true knowledge of the essences of things, for therein lies its ontological support.”112 Knowing essence begins with sense perception whereby the form of the thing is given to the intellect through the sensible and intelligible species. While the mode of the form’s existence changes—existing in reality in the entity but intentionally in the sensation and imagination—the actual intelligibility of the object is made present in sense and imagination or we could never understand the entity as it is. When we understand, our intellects are in-formed with the very same intelligibility possessed by the entity, the so-called identity theory of knowledge where the intellect becomes the object, possible since sensation and imagination possess the form and “present” it to the intellect.113 The senses “are the gateway through which things or reality pass, according to the mode of the intellect, into the latter’s immaterial possession.”114 This epistemological realism suggests that “things themselves are the cause and measure of our knowledge,” for the intellect is moved by, informed by, and ultimately measured against the form of the thing itself: “At first, the intellect is passive. Reality exists prior to the intellect. The mental image is a copy whose original is the real.”115 A coherent understanding and a true judgment occur when the intellect corresponds to the form, when it matches up to the measure of the very nature of the concrete and sensible thing. Epistemological realism in which reality exists over and against the intellect, but which sensation bridges without remainder or interference, is a necessary condition of natural law, for unless we access essence as things are, we could never determine the goods proper to the essence.116
Sensation, while necessary, concerns individuals, whereas understanding, in keeping with the theoretical mode, is abstract, universal, and about that which cannot be otherwise. The concrete individuals of sensation, however, are never abstract, never universal, and always admit of contingency, so while our understanding is identical to the original, understanding, unlike sensation, concerns the universal essence which makes the thing the sort of thing it is. When I know this tree, or that human, I do not understand them as this tree or that human, but rather understand the essence whereby trees are trees and humans
