Natural Law's Modern Cousin Germain: Ressourcement and Development

FINNIS THINKS THAT THE RATIONALISTS such as Samuel Clark made themselves easy targets for Hume's criticism, a criticism which deftly pointed out that these über-rationalistic theories were illegitimately leaping from fact to obligation, from two "is"-based premises to an "ought"-based conclusion without a middle term that coupled is to ought. Premises that were "is"-based could only yield "is"-based conclusions, not "ought"-based conclusions. So one had to give up, according to the argument, trying to construct any "ought"-based conclusions (that is, morally obligatory statements) from "is"-based premises that were predicated either upon nature or upon (speculative) reason. Practical reason as being a source of our "ought"-based premises was not something that factored into Hume's thinking since practical reason was executory of good, and not determinative of the good. Nor was it part of Hume's thinking that nature--created by God with its own ratio ordinis--might have some inner compelling inclinations, an internal movement, entelechy, or teleology, one based upon the reason of the Creator God himself, that necessarily imposed the obligatory "ought." He would not entertain the simple syllogism: we ought to act in accord with nature because nature has an order given it by God; nature suggests we should do act φ (or not do act φ); therefore, we ought to do act φ (or not do act φ).

How is it that Clarke made himself such an easy target for Hume? If Finnis is to be believed, it occurred through a historical shift or "turn," or actually two historical shifts or turns, in the thinking regarding natural law in between Thomas Aquinas (13th century) and Samuel Clarke, (late 17th early 18th century), one shift to which Clarke was heir, and one shift for which Clarke (and his fellow rationalist thinkers) were responsible. The first "turn" changed the model of natural law both in terms of the means of determine its content, and the basis of its obligation.

St. Thomas (under Finnis's interpretation) held a model that was based upon self-evident principles (and not nature) for its content. St. Thomas (again under Finnis's interpretation) held a model that with respect to obligation was built upon a "friendship" theory. As a result of the Jesuits Francisco Suárez and Gabriel Vásquez intermediated through the Dutch protestant Hugo Grotius, the natural law model shifted to a rationalistic-voluntaristic theory where content was obtained by a focus on nature and behavior fitting or unfitting to it and obligation was based upon divine command. Nature gave the "is," the divine command gave the "ought" to the "is," and the moral theory straddled both the world of "is" and the world of "ought."

According to Finnis, the Aristotelian/Thomasian classical tradition was thereby replaced by a false and unfaithful pseudo-Thomistic theory, one which sounded like Thomistic tradition but was actually a new "tradition of rationalism eked out by voluntarism." NLNR, 47. Through Suárez and Vásquez it entered into the Catholic intellectual world and took root in the early 17th century for four centuries until released through efforts of the some insightful theologians in the mid-1960s. Through Grotius it entered the Protestant intellectual world about the same time where it slowly morphed into rationalism to the extent it had any life at all, until it was practically banished in 1934 by the peremptory Nein! of Karl Barth.* In Finnis's interpretation, however, Clarke exposed himself further to Humean attack by rejecting the voluntaristic (Divine command) prong of the Suarezian/Vasquezesque/Grotian theory, and trying to bootstrap the obligation on an observation of nature, leaving himself only in the land of "is." Thus he left himself and all his progeny exposed to the attacks of Hume and of "the whole Enlightenment and post-Enlightenment current of ethics." NLNR, 47. The way out of the Humean and Enlightenment and post-Enlightenment critique according to Finnis's view is to go back to the original Aristotelian/Thomasian model based upon self-evident principles and the notion of friendship and not divine command. Since St. Thomas's development of these is insufficient, once re-acquired there must be some development. So Finnis's concept is one of ressourcement (return to the sources) and development (developing the original theory to clarify it).

According to Finnis, St. Thomas had a view of natural law that was neither rationalist or voluntarist. Instead, St. Thomas's theory of natural law was predicated, not upon nature or reason's reflection upon nature, nor upon God's will, but upon self-evident principles, whether self-evident per se, quoad omnes, or quoad sapientes.** To be sure, St. Thomas was "regrettably obscure on the question of which practical principles or precept are self evident," NLNR, 51. At best, Aquinas only "adumbrated but left insufficiently elaborated" these principles. NLNR, 47. According to Finnis, the natural law was neither based upon nature (i.e., rationalist), nor upon God's will (i.e., voluntarist), nor even upon nature cum Divine command (i.e., rationalist and voluntarist), but upon self-evident (and consequently unprovable, yet undeniable) first principles of practical reason. Essentially, however, St. Thomas's theory was neither rationalist nor voluntarist. With respect to content, St. Thomas did not advance a rationalist notion:

[W]hat is decisive [in Aquinas], in discerning the content of the natural law, is one's understanding of the basic forms of (not-yet-moral) human well-being as desirable and potentially realizeable ends or opportunities and thus as to-be-pursued and realized in one's action, action to which one is already beginning to direct oneself in this very act of practical understanding.

NLNR, 45. With regard to obligatoriness, St. Thomas did not adopt a voluntarist or Divine command (will) theory:

Aquinas . . . treats obligations as the rational necessity of some means to (or way of realizing) and end or objective (i.e., a good) of a particular sort? What sort? Primarily (i.e., apart from special forms of obligation) the good is a form of life which, by its full and reasonably integrated realization of the basic forms of human well-being, renders one a fitting subject for the friendship of the being whose friendship is a basic good that in its full realization embraces all aspects of human well-being, a friendship indispensable for every person.

NLNR, 46. In Finnis's view, then, we are obligated to follow the content of the natural law (obtained from self-evident principles) not because of a command from God, but because it is the means of friendship with God.

"Terra Nullius" by Lachlan Amore-Lloyd

In between Samuel Clarke and St. Thomas two things happened to queer the natural law doctrine and which made it so susceptible to Humean attack. The first turn or corruption according to Finnis is to be found in the version of natural law espoused and promulgated by the Jesuits Francisco Suárez (1548-1617) and by Gabriel Vásquez (1549/51-1604). Though seemingly predicated upon Aristotle and Aquinas, the theory advanced by these Spanish Jesuits "differed radically from the ethical theories actually maintained by Aristotle and Aquinas." NLNR, 45. Essentially, they dropped the Aristotelian and Thomasian reliance on self-evident principles. Instead, they advanced a combined "rationalist" and "voluntarist" theory of the natural law.

In terms of content, the reliance on self-evident principles of St. Thomas's theory was abandoned and replaced with a rationalistic basis. For Suárez and Vásquez, reason looked to human (rational) nature (and not self-evident principles) and therein discerned by a sort of extrapolation whether a certain act φ was befitting or unfitting with that nature. If it was fitting, then it was morally right. If it was unfitting, then it was morally proscribed. If φ was the only fitting act in the circumstances, then it was morally needful to to φ. This was the "rational" component of their theory.***

In moving from human (rational) nature to obligation, Suarez and Vasquez rejected the Thomasian "friendship" concept, and replaced with a Divine command theory. They required "an act of will be a superior, directing to moving the will of an inferior." NLNR, 45. This was the "voluntarist" part of their theory. The moral obligatoriness of nature, then, involved looking at whether a certain act φ was fitting (and therefore legitimate, and if φ was the only thing one could do in the circumstances, mandatory) or unfitting (in which case it was illegitimate) coupled with a divine command to follow nature. Their theory was then a blend or intertwining of rationalist and voluntarist principles.

Finnis states that this marked rationalist-voluntarist shift in the Suarezian and Vasquezesque doctrines of natural law from the Thomasian self-evident-friendship model shows itself in a shift language. Whereas those schooled in St. Thomas's original doctrine spoke of "end" and "good," those who relied on the Jesuit formulation started talking about "right" and "wrong." NLNR, 46.

It was not the original Aristotelian/Thomasian self-evident-friendship theory that made it into the influential treatise on law by Hugo Grotius (1583-1645), De Jure Belli ac Pacis, but rather the Suazerian and Vasquezesque rationalist-voluntaristic theory. It is clear from Grotius's text that the content of the natural law is obtained by rationally looking at what is fitting with human nature, and what is contrary to human nature, and then tying that determination with the divine command to follow nature. The act that was fitting to nature was commanded by God, the author of Nature. The act that was unbefitting to nature was proscribed by God, the author of Nature.

So by the beginning of the Seventeenth century, the Thomasian theory had essentially been replaced by the Suarezian/Vasquezesque model with nary a murmur by the theologians. By the beginning of the Seventeenth century, the kernel of the natural law theories was as follows:

What is right and wrong depends on the nature of things (and what is coveniens to such nature), and not on a decree of God; but the normative or motivating significance of moral rightness and wrongness, in particular the obligatoriness of the norm of right and wrong, depends fundamentally upon their being a decree expressing God's will that the right be done (as a matter of obligation) and that the wrong be avoided (likewise) . . . .

NLNR, 44.

The second "turn" is evident in Samuel Clarke (and incipient in Grotius himself), specifically Clarke's rejection of the "assumption that obligation is essentially the effect of a superior's act of will." NLNR, 44-45. In other words, of the rationalistic-voluntaristic Suarezian/Vasquezesqe/Grotian model, Clarke rejected the voluntaristic prong.**** But he retained the rationalistic part of the theory, remaining "so firmly within the grip of the thesis that practical reasoning is a matter of discerning relations of fittingness or consistency with nature that he tried to treat obligation as just one more of the set of relations of consistency."

It was these two turns that wholly corrupted the Aristotelian/Thomasian doctrine of natural law and exposed the substantially denuded and transformed doctrine of natural law to such withering attack by Hume and by Enlightenment and post-Enlightenment thinkers. But the theory of natural law that they dispatched into the grave was not the Aristotelian/Thomasian one, but rather a counterfeit. The theory they destroyed by the naturalistic fallacy was a rationalist-voluntaristic corruption sans the voluntaristic part, not the original, classical theory of Aristotle and St. Thomas which was based on self-evident principles and notions of friendship with God.

What therefore is required in Finnis's view is a ressourcement and a development of St. Thomas. We must recover his thought, says Finnis, and, where St. Thomas is deficient, we must develop it.

It is a bold theory and a bold project. One that has raised the hairs on the back of both classical and Thomistic natural law advocates, on one side, and modern consquentialists, relativists, and legal positivists, on the other side. But this is exactly what Finnis (through the work of Germain Grisez) claims to do and to have done in his Natural Law and Natural Rights. It is as if the triumvirate of Germain Grisez, John Finnis, and Joseph Boyle (who were the original collaborators and promoters of this "new" modern law theory) had boldly stepped into no man's land only to be fired on by both sides. What is not clear is whether this no man's land was once occupied by St. Thomas, a terra Sancti Thomae occupatum, or a land once occupied by Kant, a land des Kants, or a land-never-before-occupied and up for grabs, a terra nullium.

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*On Karl Barth's highly negative assessment of natural law, see a series of posting in Lex Christianorum: Karl Barth's Response to Natural Law: Nein!, Karl Barth's Tin Ear: Notes, But No Melody, and Karl Barth: Rubbing Out the Image of God in Man.
**Self-evident propositions whether of speculative reason (such as the principle of non-contradiction: something cannot both be and not be in the same way and same time) or of practical reason (e.g., one ought always to do good) were traditionally divided into those that were obvious in themselves (per se nota secundum se or per se nota secundum se tantum) and those self-evident to us (per se nota quoad nos). The latter were divided into propositions that were self-evident to all (per se nota quoad omnes) and those propositions more complicated, and which only with those with sufficient understanding of the terms could grasp their self-evident status (per se nota quoad sapientes).
***Given the texts of St. Thomas, Finnis cannot outright say that this "rationalist" thinking is not present in St. Thomas, but he essentially demotes it, insisting that this "rationalist" thinking is secondary, and that fundamentally, St. Thomas is based upon "self-evident" principles and not rationalist observations of nature. "Aquinas would not reject the Vazquez-Suarez formulae, but would give them a subordinate and derivative place in the methodology of ethics." NLNR, 45. Finnis also states that a subsidiary effect of the shift in focus was the "perverted faculty" argument, which he colors as a "late but traceable descendant of the Vazquez-Suarez conception of natural law . . . which looms large among the modern [false] images of natural law theory, that natural functions are never to be frustrated or that human faculties are never to be diverted ('perverted') from their natural ends." He calls the argument "ridiculous," but gives no basis for that judgment other than a brief reference to Germain Grisez's Contraception and the Natural Law. NLNR, 48, 55. At least six things ought to be noted about the comment. First, Finnis's extreme formulation of the "perverted faculty" argument ("never"). Second, may there a more nuanced form of the "perverted faculty" argument that is acceptable (something à la "'close-in' teleologies" advanced by Steven A. Long in his Natura Pura? See Long on Porter: "Close-In" Teleologies and the Natural Law. Third, St. Thomas appears to have had a form of the "perverted faculty" argument (certainly in the case of lying, S.T. IIaIIae, q. 110, a. 3c, which Finnis acknowledges), and indeed (fourth) a form of it can be find in authoritative documents of the Catholic Church and in its common teaching. Fifth, what is the relationship between John Paul II's "theology of the body" and the "perverted faculty" theory? If one acts against the "theology of the body," is one also not guilt of having "perverted" [the bodily] faculty" argument? Sixth, why is it "ridiculous" without argument? Finnis is more tolerant of the opinions of Hart, Raz, and positivists than the moral theologians who advocated a "perverted faculty" argument.
****This is an assertion by Finnis without any supporting reference, and, in my view, dubious. It is difficult to see how such a conclusion can be based upon Samuel Clarke's Discourse, where it seems rather clear that the will of God was invoked by him, and so he would have combined both the rationalist and voluntaristic prongs of what Finnis identifies as the Suarezian/Vasqezesque/Grotian model of natural law as compared to the Aristotelian/Thomasian model:

That the same necessary and eternal different relations that different things bear one to another, and the same consequent fitness or unfitness of the application of different things or different relations one to another, with regard to which the will of God always and necessarily does determine itself to choose to act only what is agreeable to justice, equity, goodness, and truth, in order to the welfare of the whole universe, ought likewise constantly to determine the wills of all subordinate rational beings, to govern all their actions by the same rules, for the good of the public in their respective stations: That is, these eternal and necessary differences of things make it fit and reasonable for creatures so to act: they cause it to be their duty, or lay an obligation upon them, so to do, even separate from the consideration of these rules being the positive will or command of God, and also antecedent to any respect or regard, expectation or apprehension, of any particular private and personal advantage or disadvantage, reward or punishment, either present or future, annexed, either by natural consequence, or by positive appointments, to the practising or neglecting those rules.

That though these eternal moral obligations are, indeed, of themselves incumbent on all rational beings, even antecedent to the consideration of their being the positive will and command of God, yet that which most strongly confirms, and in practice most effectually and indispensably enforces them upon us, is this, that both from the nature of things, and the perfections of God, and from several other collateral considerations, it appears, that as God is himself necessarily just and good in the exercise of his infinite power in the government of the whole world, so he cannot but likewise positively require that all his rational creatures should in their proportion be so too, in the exercise of each of their powers in their respective spheres: That is, as these eternal moral obligations are really in perpetual force merely from their own nature and the abstract reason of things, so also they are moreover the express and unalterable will, command, and law of God to his creatures, which he cannot but expect should, in obedience to his supreme authority, as well as in compliance with the natural reason of things, be regularly and constantly observed through the whole creation.

Natural Law's Modern Cousin Germain: Hume's on Our Side?

AN ENTIRE SECTION OF CHAPTER 2 of the First Part of John Finnis's Natural Law and Natural Rights is devoted to Hume's "naturalistic fallacy" as the latter stated it in his A Treatise of Human Nature. These famous words, the supposed bane of every natural law jurisprude, are written here in toto:

In every system of morality, which I have hitherto met with, I have always remarked, that the author proceeds for some time in the ordinary way of reasoning, and establishes the being of a God, or makes observations concerning human affairs; when of a sudden I am surprised to find, that instead of the usual copulations of propositions, is, and is not, I meet with no proposition that is not connected with an ought, or an ought not. This change is imperceptible; but is, however, of the last consequence. For as this ought, or ought not, expresses some new relation or affirmation, it is necessary that it should be observed and explained; and at the same time that a reason should be given, for what seems altogether inconceivable, how this new relation can be a deduction from others, which are entirely different from it. But as authors do not commonly use this precaution, I shall presume to recommend it to the readers; and am persuaded, that this small attention would subvert all the vulgar systems of morality, and let us see, that the distinction of vice and virtue is not founded merely on the relations of objects, nor is perceived by reason.

Hume, A Treatise of Human Nature, III.i.1.* This frequently-quoted passage comes at the end of a section, representing a coda, a summarization or reprise, of the prior thought.

What is remarkable is that the passage does not appear to direct itself to nature, even human nature (unless human nature were to be defined as entirely speculative reason) as a source of moral value. In fact, it comes at the end of Hume's argument that speculative reason (as distinguished from practical reason) has nothing to do with morality because speculative reason is concerned with "is" whereas actions are moved largely by passions, sentiments, and desires. It would appear that these faculties (passions, sentiments, and desires) are more similar to, though certainly not identical with, what a natural law philosophy might consider something close inclinations or "intellectual feltness,"** or at least part of the human entelechy of human nature that ought to be considered part of the greater whole of human nature. The section itself is entitled by Hume as follows: "Moral distinctions not derived from reason."***

Hume's point seems to be that the mind has only perceptions, and that these are of two kinds: ideas and impressions. He asks whether either ideas or impressions in the mind are able to distinguish between virtue and vice and to determine good from evil. In answering the question, Hume rejects any notion of "conformity to reason" as being the "measures of right and wrong," for the simple reason that it presupposes the opinion "that morality, like truth, is discerned by ideas, and by their juxtaposition and comparison." In fact, Hume rejects the notion that reason (which the context reveals he understands as "speculative" reason alone) has anything to do with governing passions, unlike morals which may have a role. "Reason of itself is utterly impotent in this particular [to excite passions, or produce or prevent actions]. The rules of morality, therefore, are not conclusions of reason." (Elsewhere, he famously states: "It is not contrary to reason to prefer the destruction of the whole world to the scratching of my finger." II.iii.3.) Moreover, since reason is an inactive faculty, a "perfectly inert" faculty, and passions and action obviously an active matter, it follows logically that reason has nothing to do with morals. "An active principle can never be founded on an inactive." This also follows because, according to Hume, reason relates to truth or falsehood. And "passions, volitions, and actions," unlike speculative truths, "are not susceptible of any such agreement or disagreement" with real relations or with the relations of ideas to existence or to facts. Passions, volitions, and actions are not true or false, which is what reason is preoccupied with. "Actions may be laudable or blameable; but they cannot be reasonable. Laudable or blameable, therefore, are not the same with reasonable or unreasonable." Indeed, "upon the whole, it is impossible, that the distinction betwixt moral good and evil, can be made to reason." The source of the laud or the blame must be elsewhere other than speculative reason.

Even though this Humean paragraph palpably deals with speculative reason as a source of morality, the opponents of the natural law have recruited the paragraph to accuse advocates of the natural moral law who rely on a broader nature (which in the case of man includes his particularly rational nature, and understands reason more broadly to include both speculative components--which aim for truth--and more importantly for morality practical components--which aim for good--and which include inclinations) of the "naturalistic fallacy." It does not seem fair to be flogged with a whip that was designed for someone else. But all's fair in love, war, philosophy, and especially ideology.

Nevertheless, as Finnis points out, the final paragraph of this section does establish what seems to be abstractly a valid enough, and hardly revolutionary, principle:

Hume [announces] the logical truth, widely emphasized since the later part of the nineteenth century, that no set of non-moral (or, more generally, non-evaluative) premisses can entail a moral (or evaluative) conclusion.

NLNR, 37.

Samuel Clarke, Hume's Real Target

As Finnis also notes, this passage, though it asserts a principle that is logically true, may be less an attack on advocates of classical natural law than an attack on eighteenth-century rationalists, in particular, Samuel Clarke (1675-1729). And indeed, it may in fact be an attack on those who neglect nature and its sound inclination (which may be part of what Hume calls the trilogy of "passions, volitions, and actions").*** It is, at least within its historical context, an attack on moral rationalism alone, a rationalism that does not give weight to natural inclinations, and tries to built a theory of morality based upon speculative reason alone, neglecting human nature's more extensive qualities of practical reason, sound inclinations, and natural teleologies. According to Hume, speculative reason alone cannot distinguish between an acorn growing from a sapling into a large oak and killing its parent and parricide. Speculative reason alone cannot distinguish between the coupling between dogs in a litter and incest between a brother and sister. The "relations" between oak and acorn, child and father, between the male and female of a litter, brother and sister are the same. Yet, as Hume himself recognizes, the moral circumstances between these relations are palpably different, the similar relation withal. Sound inclination in both cases finds parricide and incest among humans morally intolerable.

Now whether it is true or not that Hume's suggestion that speculative reason alone cannot establish the enormity of parricide or incest is besides the point. The point is that he was not taking aim at classical natural law theories, but was taking aim at hyper-rationalistic theories, corruption of the classical theories, like those developed by the Anglican divines Ralph Cudworth (1617-1688), Samuel Clarke (1675-1729), and Joseph Butler (1692-1752) who, enamored with Newtonian physics, sought to have mathematically precise moral theories based upon reason alone, and theories, moreover, that ignored nature and its inclinations.† These were Protestant Christian versions of morals ad more geometrico.

In fact, it appears that Hume's principal target in this section seems to have been Samuel Clarke's work with a rather cumbersome title, A Discourse concerning the Unchangeable Obligations of Natural Religion, and the Truth and Certainty of Christian Revelation (herein Discourse). A comparison of what Clarke taught and Hume's wording in this section make it rather apparent that he was criticizing--not classical natural law--but natural law a la Clarke.

Samuel Clarke, an Anglican cleric (he was rector of St. James Westminster from his appointment in 1705 to his death in 1729), was influenced by Descartes, with whom he had a sort of love-hate relationship. Clarke appeared to have accepted a Cartesian distrust of senses as the source of ultimate knowledge. He seems also to have accepted a Cartesian dualism between body and soul: mind is mind, matter is matter, and never the twain shall meet but by a form of fortuitous occasionalism. But if his relationship with Descartes was mixed, his relationship with Newton was quite a relationship of love and devotion. Clarke was an unflagging advocate of Newton, and a great supporter of Newton's physical and mathematical thought. He was perhaps best known for his correspondence with Leibniz on the matter of Locke, Newton, and English philosophy in general.

Clarke's thoughts on moral philosophy are concentrated in the second of his Boyle Lectures (delivered in 1705) which were later published as the Discourse. The Discourse is organized around a set of fifteen propositions. As Clarke summarized his ethical work, he "endeavoured to deduce the original obligations of morality, from the necessary and eternal reason and proportions of things." NLNR, 38-39. It is important to point out that Clarke did not look and man's nature as a source of "original obligations of morality," but looked at something that he called the "eternal different relations, that different things bear to one another." It is the relations of things, and in particular the fitness of things which was the source of moral obligation. Therefor it was the fitness of things that for Clarke was the source of moral law. It was a curious, rather vague theory, not particularly a classical natural law theory at all. There is nothing in Clarke's theory of practical reasoning or of inclinations. His aim was to construct a theory of morals that was exact, to build something in morals similar to what Newton had effected in mathematics or in physics. And he obviously confused speculative reason and practical reason.

In his quirky ethical theory, Clarke†† starts with the difference of things:

That there are differences of things, and different relations, respects or proportions of some things towards others, is as evidence and undeniable as that one magnitude is greater, equal to, or smaller than another.

This is, as it were, the foundation of Clarke's moral theory. It was the "differences of things" that gave rise to duty, that gave rise to law. The law arose from the "properties and relations," in the "proportions," of those different things. The properties and relations and proportions of things were "of eternal necessity," are part of the "things themselves," and so are "absolutely unalterable." Clarke distinguishes between things natural or mathematical (such as figures, numbers, weights, colors, etc.) and things moral (persons, actions, and circumstances), and his moral theory is concerned with things moral, i.e., persons, actions, and circumstances. Ultimately, however, everything comes down to relations between persons. As James Edward LeRossignol††† summarizes it:

Actions are actions of persons, circumstances are circumstances of persons. therefore things moral are in reality only persons, in their various relations to themselves and other persons.

LeRossignol, 37.

Just as the relations and proportions between things natural or mathematical are "eternal and unchangeable" (e.g., the relationship between the area of a circle and its radius is eternally and unchangeable A = πr² or the law that two parallel lines will never enclose a space because they will never meet), so likewise are the proportions and relations among things moral "eternal and unchangeable." Thus there are proportions and relations between persons, actions, and circumstances that are "eternal and unchangeable."

From this base, Clarke introduces another concept: the "fitness of things." There is a certain "fitness" or "agreement or disagreement" of things moral. That is, with respect to the proportions and relations between persons, actions, and circumstances, there is a certain "fitness" or a certain "agreement or disagreement." As Clarke himself says it:

That from these different relations of different things there necessarily arises an agreement or disagreement of some things with others, or a fitness or unfitness of the application of different things or different relations, is likewise as plain as that there is any such thing as proportion in Geometry and Arithmetic, or uniformity or difformity in comparing together the respective figures of bodies.

This "fitness of things," their "agreement or disagreement," is, for Clarke, the moral law. It predates, precedes any human positive law, and no law or opinion of man can change this inherent "fitness " or "agreement or disagreement" in things moral. As LeRossignol describes Clarke's view:

As no law or opinion of men can change the differences of things, so no human law or opinion can in the least degree alter the fitness of things. As things existed before all positive law, institution, or government, so no law or power, not even of an all-powerful Leviathan, can alter the eternal distinctions of right and wrong. So long as things exist, just so long do the fitnesses of things remain unchangeable, as the law of nature to man and the rule which God himself follows in the government of the world.

LeRossignol, 40. There is both a fitness of ends, arising largely from relations between persons, and a fitness of means, and indirect fitness relating to the relationship that actions have to those ends. In this latter view, he seems to brush up against an incipient utilitarianism.

Clarke states that there is a common consensus or common agreement on the relations and proportions in both mathematical and natural realms and in the moral realm. Clarke insists that "the differences, relations and proportions of things both natural and moral, in which all unprejudiced minds thus naturally agree, are certain, unalterable and real in the things themselves." So there ought to be in the uncorrupted and unprejudiced mind similar assents to moral truths as there are to mathematical or natural truths. Thus what is "fitting," what is "agreeable," and what is therefore morally good, is something that is perceivable by reason.

Now what these eternal and unalterable relations, respects, or proportions of things, with their consequent agreements or disagreements, fitnesses, or unfitnesses, absolutely and necessarily are in themselves, that also they appear to be, to the understanding of all intelligent beings; except those only who understand things to be what they are not, that is, whose understandings are either very imperfect or very much depraved.

There are some obvious lacunae in Clarke's thought, the most apparent being that he "nowhere gives a definition of the words fit and fitness," leaving the central part of his moral philosophy also "the most obscure part of his ethical philosophy." LeRossignol, 45-46.

With this most elementary of introduction into Samuel Clarke's notions of relations and fitness (which are the driving forces of his moral theory), it is apparent at once that Hume is referring to Clarke's moral theory in this section of his Treatise. Hume's invocation of Clarke is unmistakable. "Those who affirm that . . . there are eternal fitnesses and unfitnesses of things" are proposing that "morality, like truth, is discerned merely by ideas . . . ." "But . . . to show, that those eternal immutable fitnesses and unfitnesses of things cannot be defended by sound philosophy . . . ." "If . . . the character of virtuous and vicious . . . must lie in some relations of objects . . . ." "There has been an opinion very industriously propagated by certain philosophers, that morality is susceptible to demonstration . . . . to an equal certain with geometry or algebra. Upon this supposition, vice and virtue must consist in some relations . . . ." Hume's focus on the notions of fitness and relations in the matter of morals in this section of his Treatise is a clear reference to Clarke's presentation of his moral theory in the latter's Discourse.‡

There is then a certain "unfitness of things," if we may be allowed to adopt Clarke's words, when opponents of natural law invoke Hume's argument against someone advocating a theory of morality which is clearly not a classical theory of natural law, and then using that argument (an argument that Hume himself ignored when it served his purposes) against another theory altogether. It is somewhat akin to blaming a grandfather for the faults of his grandchild, and a double bastard grandchild at that.

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*I have updated the spelling and spelled out the words that have been contracted.
**The term "intellectual feltness" is my term, and is my best grasp of the notion of inclination, which is something that is based upon the faculty of reason, but is something that is almost impulsive or felt, something fundamental, and ordering, a tendency, an intellectual, if not entirely conceptually rational, entelechy. The subject has been treated in various postings, but one may access the discussion of inclination and natural law in the context of the natural law teachings of Jacques Maritain. See Jacques Maritain and Natural Law: Inclination and Law.
***In natural law literature, reason and human nature are sometimes treated as equivalent terms. Because man's nature is as a rational animal, the term "reason" is used as a synecdoche for human nature as a whole. But the reason that is equated with human nature is something different from mere speculative or theoretical reason (that reason concerned with truth); rather, it is a reason that incorporates, in addition to the speculative, the practical reason, a reason whose purpose is to grasp the good. The reason that Hume attacks here is speculative reason. For Hume, the practical reason was not the source for determination of good; rather, it was only a means, a "slave of the passions," see Treatise, II.iii.3. It is for this reason that Copleston's assessment (see Note † below) would appear wrong.
****In fact other than pure speculative reason, Hume was suggesting other "mental factors, such as conscience, moral sense, sentiment, and other passions." NLNR, 38, n. 44; Treatise, III.i.1.
†Indeed Frederick Copleston, S.J., detected remnants of natural law thinking in Hume behind this critique:

[Hume's] insistence on the original constitution or fabric of human nature suggests that this nature is in some sense the foundation of morality or, in other words, that there is a natural law which is promulgated by reason apprehending human nature in its teleological and dynamic aspect.

Frederick Copleston, History of Philosophy (Westminster, Md: Newman Press, 1959), Vol. 5, 34 (cited in Howard P. Kainz, Natural Law: And Introduction and Re-Examination (Peru, Ill.: Carus Publishing, 2004), 71). As Kainz observes, some more extreme defenders of Hume even call him a "'closet' natural lawyer." Kainz, 71. It is true that, Hume himself would seem to betray his own principle in that he suggests that ethics be "founded on fact and observations" about what sorts of characteristics and actions bring about moral approbation or disapprobation from men. NLNR, 37 n. 42; See An Enquiry Concerning the Principles of Morals, § 1. Even though Hume invokes certain aspects of human nature (volition, passions, sentiments) in his moral theory, I certainly would not place the skeptic Hume in the natural law camp, and certainly not in any classical or Thomistic natural law camp. More probable is the view that Hume advocated something similar to the "moral sense" theory of Hutcheson, rather than any concept of natural law. Kainz, 72. Finnis has a very interesting observation on Hume. Not only is Hume inconsistent with his own principle in building Humean "oughts" from "ises," Hume lapses into another fallacy beyond that of reasoning from "is" to "ought." He also seems to confuse "ought" to "will" or "must," that is, that something is morally obliging only if it in fact is forcibly compelling. NLNR, 41 (Those who find the "naturalistic fallacy" argument contained in Hume's words in III.i.1 "should be disconcerted by this manifestation of Hume's indifference to the distinction between the 'forcible' and the 'obligatory', between what ought to move the will and what 'must' (i.e., necessarily does) move it.")
††Clarke's Discourse is available on line at various places, most conveniently as the Christian Classics Ethereal Library. See Discourse.
†††James Edward LeRossignol, The Ethical Philosophy of Samuel Clarke (G. Kreysing 1892) (hereinafter LeRossignol).
‡Hume himself in other writings expressly confirms this. See NLNR, 38, n. 46.