The rebirth of natural law ethics and politics in the last forty years has been encouraging and fruitful. However, this movement cannot attain maturity until it is placed within a thorough and comprehensive metaphysical framework. In this third and final installment of our series on natural law ethics (see parts one and two), we want to do two things: First, survey contemporary English-language philosophy in order to show why the intellectual climate is apt for integrating ethics into a philosophy of nature. Second, we want to compare briefly our proposal with the “new natural law theory” developed by Germain Grisez, Joseph Boyle, John Finnis, and their collaborators, because this school of natural law is distinctive for urging the separateness of moral theory and the philosophy of nature.

That the aversion to metaphysics is outdated finds persuasive evidence in the evolution of Alasdair MacIntyre’s views in the twenty years from After Virtue (1981) to Dependent Rational Animals (2001). In the former work, MacIntyre recommends an Aristotelian, narrative-based ethic, shorn of Aristotle’s “metaphysical biology.” In the latter, MacIntyre endorses and develops just such a metaphysical biology. MacIntyre’s change of mind reflects a broader change within the world of analytic philosophy: the revival of rational metaphysics, including, in particular, a neo-Aristotelian framework.

Metaphysics in the English-speaking world reached its nadir during the heyday of logical positivism in the 1920s through the 1940s. Positivists dismissed metaphysics, along with ethics and theology, as not just wrong but nonsensical. They saw philosophy’s role as the handmaiden to the natural sciences, cataloguing and systematizing the theories and practices of the empirical scientist. Then something truly marvelous and almost unprecedented in the history of philosophy happened: a philosophical movement suffered a series of refutations so thoroughgoing that even its most ardent defenders abandoned it. In the aftermath of positivism’s collapse, metaphysics revived on a global scale. The metaphysical systems developed by Bertrand Russell and Alfred North Whitehead during the positivist period gained new strength, and Willard Van Orman Quine brought the classical questions of ontology back to the center of focus. David K. Lewis, one of Quine’s students, and Lewis’s many students both in America and Australia helped to make metaphysics, once again, the most popular and most central of philosophy’s sub-fields, supplanting philosophy of language and philosophy of science.

Although positivism is vanquished, the ontological and metaphysical projects launched by Quine and his successors continue to be laced with some of the scientistic and physicalist prejudices that motivated the Logical Positivists. Brown University’s Roderick Chisholm was largely responsible for the restoration of metaphysics to its classical foundations, unhampered by an excessive deference to the primacy of physics. Chisholm, who wasn’t a Catholic, is said to have been fond, nonetheless, of reading from St. Thomas’s Summa Theologiae each morning to limber up his mind. He forged a link between contemporary analytic philosophy and the Aristotelian metaphysics and philosophical psychology of the Austrian philosopher Franz Brentano. According to one estimate, Chisholm’s academic descendants (students, students of students, etc.) now number at least 283 professors, placing him in the top five in the twentieth century, with Whitehead, Quine, Hans Reichenbach, and Hilary Putnam.

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With the revival of metaphysics generally came a renewed attention to the problems of the structure of space and time (e.g., the problem of the continuum) and the problem of the unity and persistence of material objects. In both cases, contemporary metaphysicians have re-discovered the enduring virtues of the Aristotelian answer, according to which certain wholes (the “substances” and “activities”) are ontologically and explanatorily prior to their parts, reversing the bottom-up, atomistic approach characteristic of both ancient and modern materialism. This neo-Aristotelian project has attracted the support of Roderick Chisholm in Person and Object (1979) and On Metaphysics (1989), David Wiggins in Sameness and Substance (1980), Peter van Inwagen in Material Beings (1995), Trenton Merricks in Objects and Persons (2003), as well as Dean Zimmerman and John Hawthorne in a number of works. Alvin Plantinga revived the study of metaphysical possibility and necessity in The Nature of Necessity (1979), and Saul Kripke’s celebrated Princeton lectures Naming and Necessity (1980) and Hilary Putnam’s essay “The Meaning of ‘Meaning’” (1975) rehabilitated the notion of essence, both of kinds and of individuals. Scientific essentialists of various stripes now include David M. Armstrong, Brian Ellis, Stephen Yablo, E. J. Lowe, D. H. Mellor, Alexander Bird, and Nancy Cartwright. In his recent book Modality and Tense (2005) and several papers, Kit Fine has adumbrated a fully Aristotelian account of essence, accident, form, and matter.  Oxford philosopher Peter Hacker has defended a neo-Aristotelian philosophical anthropology in his recent book Human Nature: The Categorial Framework (2007).

The notion of causation, which Humeans and positivists had attempted to replace with mere observable regularities, and which in 1912 Bertrand Russell had declared to be obsolete, was reborn in the latter half of the twentieth century, as causal theories of reference (Kripke, Gareth Evans), personal identity and material persistence (Sydney Shoemaker), perception (Paul Grice), memory, and knowledge (Alvin Goldman) proliferated. Michael Tooley, Doug Ehrlich, Phil Dowe, David Armstrong, and many others have offered anti-Humean, strongly realist accounts of causation. Even the notion of teleology (or final causation) has been defended by staunch naturalists like Ruth Garrett Millikan, Fred Dretske, and Larry Wright, and employed by Alvin Plantinga in an influential theory of knowledge from his book Warrant and Proper Function (1993).

Recent years have also seen the emergence of a group of metaphysicians and philosophers of mind, many of them dubbed “analytic Thomists,” including John Haldane, Peter Geach, Anthony Kenny, David Oderberg, Eleonore Stump, Michael Loux, Brian Leftow, J. P. Moreland, Edward Feser, Alexander Pruss, James F. Ross, Gyula Klima, Stephen Brock, and David Braine.  In various ways, they have sought to bring Aquinas to bear on contemporary philosophical issues—or to show why contemporary “problems” can be dissolved by recovering a Thomistic insight.

In the field of ethics and human action, a parallel development of Aristotelian themes has taken place. David Hume’s so-called is/ought gap was exploded as fallacious by the late Elizabeth Anscombe in her essay “Modern Moral Philosophy” (1958), and her colleagues Philippa Foot and Rosalind Hursthouse extended her critique, most recently in two important books, Natural Goodness (2001) and On Virtue Ethics (1999), respectively. From a different perspective, Hilary Putnam has attacked the Humean orthodoxy in his book Beyond the Fact/Value Dichotomy (2001), while others have defended a more or less Aristotelian account of the virtues as grounded in the teleology of human nature (e.g., John McDowell, Martha Nussbaum, and Amartya Sen). Anscombe’s book Intention (1957) and the works of her students—Anthony Kenny’s Action, Emotion and Will (1963), and Charles Taylor’s The Explanation of Behavior (1964)—introduced an Aristotelian-Thomistic conception of human action to the analytic mainstream, an effort to which Alan Donagan further contributed with The Theory of Morality (1979) and Choice: the Essential Element in Human Action (1987). More recently, Candace Vogler, Michael Thompson, Warren Quinn, Gavin Lawrence, Anselm Müller, and others have taken up Anscombe’s cause and have continued to advance Aristotelian-Thomistic moral theory in an analytic context.

The aforementioned trends and developments are by no means homogenous and they include ideas, assumptions, and tendencies that a solemnly professed Thomist or Aristotelian of the strict observance would find otiose. But it is safe to say that from an Aristotelian-Thomistic perspective, and particularly with the prospects of natural law theory in mind, English-language philosophy in 2011 is in a much healthier state than it was in 1911. Given this fact, it is astonishing that many non-analytic philosophers today still think that analytic philosophy just is logical positivism. Even our potted history of the analytic tradition above should be enough to dispel this assumption.

We have said nothing thus far about the school of natural law ethics that since the second half of the twentieth century has emerged as most influential and distinctive, namely the “new natural law theory” (NNL) developed by Grisez, Finnis, and Boyle. NNL is characteristic for urging the priority of the agent’s perspective in moral theory, as opposed to the observer’s, and although this might seem contrary to our recommendation of a metaphysically-integrated ethics, this conclusion would be too hasty. For the NNL has never argued for the absolute autonomy of ethics from nature. Rather, the NNL has claimed that ethical knowledge is acquired from the first-personal perspective of an agent reflecting on his practice; but such knowledge is made true by human nature. In other words, if human nature were different, then our practicable goods would be different; we come to know those goods not by speculation about human nature, but by reflecting upon the practices we already see as good—friendship, family, religion, play, and so on.

There is much truth in this claim, and in large part, it is a restatement of Aristotle’s remark in the Nicomachean Ethics that there is a difference between arguing towards first principles and arguing from them, between the order of knowing and the order of being. Nonetheless, the NNL claim is stronger than this, because it represents moral theory as a one-way street. That is, it holds that we can infer facts about our natural capacities from ethical experiences, but it rejects the idea that ethical conclusions, or indeed, conclusions about human action, can be inferred from facts about our natures.  This stronger claim is dubious, however. It is much more plausible to say that we can infer both from ethical truths to natural facts and from natural facts to ethical truths.

Take three examples of inference from facts to values: from the fact that you hand me certain green pieces of paper, I can infer that I now owe you $20; from the fact that a tree’s roots are wide and numerous, I infer that the tree is healthy; from the fact that another beer would make me woozy, I infer that my drinking it would be intemperate. All three of these inferences share the same logical form, and all three derive values—owing, healthfulness, and intemperance—from natural facts. There is nothing logically distinctive about the third inference, which is the only ethical one, and so unless there is something suspect about the first two, there is no general problem with “deriving” ethical conclusions from natural premises. Furthermore, it doesn’t matter whether these inferences are made from the third- or first-person perspective, because either way they are valid. It is true that the validity of these inferences presupposes certain contexts (viz., about institutions, plant species, and human flourishing), but this doesn’t undermine the general point. Nature is dynamic and suffused with value. Values are inferable from facts, because values consist in facts.

In short, there is no logical gap preventing inferences from facts to values, unless you define ‘fact’ and ‘value’ arbitrarily in order to manufacture such a gap, as Hume did. Hume’s is/ought gap was an implication of his simplistic, empiricist psychology, according to which he defined reason as an inert capacity for discovering matters of (valueless) fact or manipulating relations of ideas. This psychology also ensured the truth of Hume’s famous dictum, “Reason is, and ought only to be the slave of the passions, and can never pretend to any other office than to serve and obey them.” The Humean man’s passions push and pull while his reason sits astride as permanent observer. Once we reject this bad psychology, as most philosophers have done, there is no more reason to be deferential to a fact/value gap or a passion-enslaved conception of reason.

We would argue that NNL is poised for rapprochement with the more self-consciously naturalistic strains of the natural law tradition as the ghosts of Hume are more thoroughly exorcised from contemporary philosophy. NNL already implicitly rejects Humean psychology, because it rightly rejects the instrumentalized, passion-enslaved conception of practical reason. NNL recognizes that the natural ends of human life are fundamentally goods of reason, because human beings are, by definition, rational animals. The contrast of ‘facts versus values’ is just one more false dichotomy ripe for dissolving.

Our discussion here only skirts the surface of controverted intramural debates within the natural law tradition.  These debates will find new resources for irenic and fruitful resolution if natural law theorists of all stripes turn to engage the mainstream English-language philosophy, which is more open to the claims of nature than it has been for decades.