Losing the Forest for the Tree: Why All Thomists Should (Not) Be River Forest Thomists

Abstract

One of the most influential and controversial schools of 20th century Thomism—especially in North America—is the “River Forest School” or “River Forest Thomism”. And one of the most influential and controversial theses associated with that school is the thesis that metaphysics cannot be established as a distinct and autonomous science unless one has already proven the existence of a positively immaterial being. The purpose of this paper is to show that River Forest Thomism cannot and should not be reduced to that controversial thesis. As such, rejection of the thesis cannot and should not constitute a rejection of the school. Indeed, as soon as we understand what River Forest Thomism was really about, it will become clear that all Thomists should be River Forest Thomists.

1. Introduction

It is easy to lose the forest for the trees. It is a bit harder to lose the forest for a single tree, but it still happens. It happens when we fixate so much on a single problem, a single question, a single issue, that we lose sight of what is really at issue—what really matters for the larger project in which we are engaged. When it comes to the various schools of 20th century Thomism, no school is more in danger of losing the forest for the trees—indeed, of losing the forest for a single tree—than the River Forest School.1 The purpose of this article is to ward off that danger. As such, it is intended to serve as a defense of River Forest Thomism.

Many, however, both among those who identify as River Forest Thomists and among those who do not, might see it as an attack on River Forest Thomism. The reason is that there are many who have already lost the forest for the trees—indeed, who have already lost the forest for a single tree. The “forest” I have in mind is what is really at issue, what really matters for the larger project of River Forest Thomism. The “tree” is a single thesis to which River Forest Thomism is all-too-often reduced, both by those who identify as River Forest Thomists and by those who do not. The single thesis is this: the existence of a positively immaterial being must be demonstrated in order to establish metaphysics as a ‘scientia’ distinct from natural philosophy.2

Given the distinction between forest and tree, I will draw a corresponding distinction between River Forest Thomism and “River Forest Thomism”. The former is the forest—i.e., the larger project of rigorous and methodologically reflective engagement with the natural sciences on the part of contemporary Thomists. The latter (and yes, the quotation marks are to be read as scare quotes) is the tree—i.e., the particular thesis just stated. The forest, I argue, must be preserved. The tree, however, must be cut down. In other words, while all Thomists should be River Forest Thomists, no Thomists should be “River Forest Thomists”.

2. The Forest

The founder of the River Forest School of Thomism was the American Dominican friar William Humbert Kane (1901–1970).3 Fr. Kane was ordained a priest in 1927 and studied medicine before being sent to Rome to pursue a doctorate in philosophy. While studying at the Angelicum, he came under the tutelage of Fr. Anicetus Fernández-Alonso, (d. 1981), a Spanish friar and natural philosopher who became the Master of the Dominican Order from 1962 to 1974. After completing his dissertation in 1930, Kane returned to the U.S. and began a long career of teaching at what was then his province’s house of philosophical formation, located in River Forest, Illinois.

Though Fr. Kane’s research interests had already settled on natural philosophy, it was during his time serving as lector primarius in River Forest (1933–1940) that his distinctive approach came into sharper focus. In 1936, he read an article published by his former teacher, Fernández-Alonso, on the subject of science and philosophy according to Albert the Great (Fernández-Alonso 1936). Convinced by Fernández-Alonso’s criticisms of then-current Neo-Scholastic accounts of the relationship between (natural) philosophy and the contemporary sciences, Kane developed his teacher’s line of thought and passed it along to his students—two of whom were Raymond J. Nogar, O.P. and Benedict M. Ashley, O.P.

On 15 November 1951, after three years of teaching natural philosophy in Rome, Fr. Kane returned to the United States and, together with the newly ordained Frs. Nogar and Ashley, established the Albertus Magnus Lyceum for Natural Science at the studium in River Forest. The purpose of this institute was to promote dialogue between philosophers and scientists, and its summer sessions and publications continued until 1969. From 1957 to 1965, Fr. James A. Weisheipl, O.P., an Oxford-trained historian of medieval science, taught philosophy at the school and became heavily involved with the Lyceum. Fr. William A. Wallace, O.P., a prolific natural philosopher and historian of Galileo, was also actively involved in the work of the Lyceum. These five—Kane, Weisheipl, Wallace, Nogar, and Ashley—formed the core of what came to be known as the River Forest School.4

While the Albertus Magnus Lyceum closed in 1969 and the studium in River Forest followed suit just a few years later, the River Forest Thomists continued to exercise significant influence—especially in North America—through their teaching and publications.

With this history in mind, we can now raise the question that lies at the heart of the present inquiry: what does it mean to be a River Forest Thomist? What were the characteristic concerns that set River Forest Thomism apart from the other 20th century Thomistic schools?

As the brief history just given makes clear, the answer to this question has something to do with the place of natural philosophy in the broader context of (a) philosophy as a whole and (b) its relation to the natural sciences. But what? I propose that the best way to understand what was really at issue—what really mattered—to the core figures of River Forest Thomism (and so for River Forest Thomism itself), is to compare three sets of theses associated with the River Forest School. These sets of theses are (1) the three principal theses of Anicetus Fernández-Alonso’s (1936) article, which set Fr. Kane’s intellectual trajectory and can be thought of as the Ur-source for River Forest Thomism, (2) the four theses articulated by Fr. Weisheipl in his introduction to a 1961 festschrift honoring Fr. Kane (See Weisheipl 1961, pp. xvii–xxxiii), and (c) the eight theses articulated by Fr. Ashley in his contribution to a 1991 festschrift honoring Fr. Weisheipl (See Ashley 1991, pp. 1–15). These three sets of theses, separated by intervals of roughly thirty years, provide us with the best possible insight into the developing self-understanding of the River Forest School.

The main concern of Fernández-Alonso’s “Scientiae et Philosophia secundum S. Albertum Magnum” was to articulate and defend the autonomy of natural philosophy. In the period leading up to the Neo-Scholastic revival, seminary textbooks had been heavily influenced by non-scholastic philosophy (See Weisheipl 1962). One consequence of this was that Aristotelian natural philosophy had been cut from seminary curricula and replaced by Cartesian or, later, Newtonian mechanics. Moreover, the aspects of Aristotelian natural philosophy that remained (e.g., cosmology and philosophical psychology) were subsequently incorporated into metaphysics (specifically, into what came to be known—at least after Wolff—as “special metaphysics,” in contrast to “general metaphysics”) (in addition to Weisheipl 1962, see McCool 1989, 1994, 1999). Fernández-Alonso’s goal was to push back against these trends and reestablish the importance of the philosophy of nature, both for the philosophical formation of seminarians and for the discipline as a whole. To this end, he argued at length for three key theses:5

Fernández-Alonso’s Theses

(1)

Natural philosophy is neither formally nor materially distinct from the non-mathematized natural sciences.

(2)

Natural philosophy is formally, but not materially, distinct from the mathematized natural sciences.

(3)

Natural philosophy is both formally and materially distinct from metaphysics.

To say that natural philosophy is “neither formally nor materially distinct from the non-mathematized natural sciences” is to say that the natural sciences are, full stop, the various parts of natural philosophy—provided that we understand them to be non-mathematized. For a science to be “mathematized” is for it to employ mathematics in its reasoning about nature. Thus, zoology will be mathematized to the extent that it employs mathematics in reasoning about animals and non-mathematized to the extent that it does not, botany will be mathematized to the extent that it employs mathematics in reasoning about plants and non-mathematized to the extent that it does not, and chemistry will be mathematized to the extent that it employs mathematics in reasoning about chemicals and non-mathematized to the extent that it does not. For ease of reference, we can call the former “mathematical zoology”, “mathematical botany”, and “mathematical chemistry” and the latter “natural zoology”, “natural botany”, and “natural chemistry”. The first thesis above, then, states that natural zoology, natural botany, and natural chemistry are all branches of natural philosophy.

What about the mathematized versions of these disciplines? On the one hand, everything studied in mathematized chemistry will also be studied in natural chemistry and vice versa—and likewise for the other disciplines. On the other hand, the way in which something is studied in mathematized chemistry is different from the way in which something is studied in natural chemistry—and likewise in the other cases. Consider, for example, the difference between the questions “what is it for water to boil?” and “at what temperature does water boil?” The former could plausibly be answered without invoking numbers, shapes, quantities, etc. The latter could not (for temperature is a quantified measure of average kinetic energy). Thus, mathematical chemistry will approach the same subjects of inquiry as natural chemistry, but it will do so in a different way—i.e., by applying mathematical concepts and principles to its study of chemical substances and their properties. This is what Fernández-Alonso means by saying that they are formally, but not materially, distinct sciences.

The third thesis states that natural philosophy and metaphysics are entirely distinct sciences—i.e., that they have non-identical domains and non-identical ways of studying what falls under those domains. While this may strike present-day Thomists as obvious, it was perhaps the most controversial of the three theses among Fernández-Alonso’s Thomistic contemporaries. And the same thing will almost certainly be true of present-day non-Thomists: philosophers in the analytic tradition, for example, typically consider questions about material constitution, the nature of time, diachronic identity, and hylomorphism to be metaphysical questions, in contrast to questions about chemical constitution, time dilation, and diachronic evidence, all of which they typically consider to be scientific questions. For the Thomist, however, questions about hylomorphism, change, time, and material constitution—along with all the more particular and determinate forms that such questions might take—belong to natural philosophy. As such, Fernández-Alonso’s third thesis remains relevant for any Thomist interested in dialoguing either with contemporary analytic metaphysicians or with contemporary natural scientists.

Thirty years after the publication of Fernández-Alonso’s article—and well after Kane had established the River Forest School—James Weisheipl was tasked with writing an introduction to a festschrift honoring Kane. In that introduction, Weisheipl reflected on the history, aims, and commitments of the River Forest Thomists as they had developed up to that point. He proposed four theses to capture what River Forest Thomism was all about. These theses were as follows (see Weisheipl 1961, pp. xxx–xxxi):

Weisheipl’s Theses

(1)

The non-mathematical parts of modern science belong to a single science: natural philosophy, or the science of nature.

(2)

Formally mathematical sciences, or mathematical-physical sciences, are really distinct from natural philosophy or the science of nature.

(3)

Natural philosophy, or the science of nature, is autonomous in its own field and is prior to and independent from metaphysics in the order of learning.

(4)

At both the general and the particular levels, natural philosophy or the science of nature admits of different degrees of certainty (e.g., demonstrative, probable, tentative, etc.)

Weisheipl’s first two theses correspond almost exactly to Fernández-Alonso’s first two theses. To say that the non-mathematical parts of modern science belong to natural philosophy is just to say that they are the parts of natural philosophy—which is precisely what Fernández-Alonso meant by saying that they are neither formally nor materially distinct from natural philosophy. Similarly, to say that the mathematical–physical sciences are “really distinct from” natural philosophy is just to say that one is not engaged in natural philosophy when one engages in mathematical–physical science—which is precisely what Fernández-Alonso meant by saying that the two are formally distinct even when they treat materially the same subjects.

Weisheipl’s third thesis corresponds to and expands upon Fernández-Alonso’s third thesis. To say that natural philosophy is “autonomous in its own field” is, at least in part, to say that it is materially and formally distinct from metaphysics. But it is also to say that natural philosophy is not intrinsically dependent upon metaphysics. For the River Forest School, it is important to recognize that one need not be a metaphysician in order to be a natural philosopher. In fact, the final part of Weisheipl’s third thesis says that, at least from a pedagogical perspective, the order of priority is reversed. If we want to learn metaphysics well, we need to have first learned natural philosophy. This is because both the objects studied in and the methods employed by natural philosophy are better suited to the human mind than those of metaphysics—and it is a general pedagogical rule that we ought to start with what is better-known from our perspective and build up to what is harder for us to understand.

Weisheipl’s fourth thesis does not directly correspond to one of the theses defended by Fernández-Alonso. Nevertheless, it can and should be understood as entailed by and a defense of thesis 1. If the non-mathematical parts of modern science are not really distinct from the parts of natural philosophy, and natural philosophy is at least in principle an Aristotelian science—i.e., a scientia or episteme, sc., knowledge of necessarily true conclusions on the basis of necessarily true premises—then the non-mathematical parts of modern science must at least in principle be parts of an Aristotelian science. In other words, modern science (at least in its non-mathematized form) must be able to yield demonstrative knowledge in the Aristotelian sense of “demonstration”—i.e., it must be able to draw universal and necessary conclusions from universal and necessary premises.

This, however, was denied by a great many Thomists in the 20th century and not without reason. We often associate modern science with the scientific method, and we often associate the scientific method with falsifiability. But the drawing of universal and necessary conclusions from universal and necessary premises seems to be at odds with an experimental methodology based upon the testing of falsifiable hypotheses.6

Weisheipl’s fourth thesis, then, claims that worries, such as these, are ill-founded. It may be true that modern scientific practice usually does proceed in a way that leads to merely dialectical (i.e., probable) conclusions (e.g., by introducing a hypothesis and showing how that hypothesis fits our observational data), but it need not do so of necessity. The modern sciences, Weisheipl insists, can—and on occasion do—produce genuine demonstrations.7 Since natural philosophy and the contemporary natural sciences both have dialectical and demonstrative moments, there is no principled reason for denying that the latter stand to the former as the more determinate parts thereof.

With this basic understanding of Weisheipl’s theses in hand, we can now fast-forward another thirty years, to the 1991 publication of Benedict Ashley’s “The River Forest School and the Philosophy of Nature Today.” Like Weisheipl did in his introduction to the festschrift honoring Kane, Ashley similarly used his contribution to the festschrift honoring Weisheipl to reflect upon the River Forest School and articulate what he considered to be its most salient characteristics. Ashley identified eight:

Ashley’s Theses

(1)

Aquinas’s philosophy is best drawn from his Aristotelian commentaries.

(2)

Aquinas should be interpreted as a convinced Aristotelian.

(3)

Aquinas’s order for learning the sciences is also necessary for establishing those sciences; thus, metaphysics cannot be established without natural philosophy.

(4)

Natural philosophy and natural science are united in object, scope, and method.

(5)

Aquinas’s natural philosophy is best understood in light of Aristotle’s logical works, especially the Posterior Analytics.

(6)

Seeming differences between contemporary natural sciences and natural philosophy are either only apparent differences or are non-essential.

(7)

Aristotelian natural philosophy provides the tools for resolving present-day scientific paradoxes.

(8)

Neither metaphysics nor theology can supply the necessary theoretical basis for the modern sciences.

Reading these theses in light of those supplied by Weisheipl and Fernández-Alonso, it should be clear that there is a far greater gap between Ashley’s theses and Weisheipl’s than there was between Weisheipl’s theses and Fernández-Alonso’s. This is not to say that there is no connection between Ashley’s list and those that came before—there most certainly is. But where Weisheipl’s list recapitulated all of Fernández-Alonso’s theses, Ashley’s list does not (his list is missing a correlate to their thesis 2).8 And where Weisheipl’s list added to Fernández-Alonso’s list only what could plausibly be characterized as an entailment thereof, Ashley’s list does not.

We should begin our comparison, however, with the points of continuity. Ashley’s fourth thesis obviously corresponds to the first thesis on Fernández-Alonso’s and Weisheipl’s lists, and his eighth thesis obviously corresponds to Fernández-Alonso’s and Weisheipl’s third thesis. Less obviously, I think Ashley’s sixth thesis corresponds to Weisheipl’s fourth. This is because the “seeming differences between contemporary natural sciences and natural philosophy” that Ashley has in mind are connected with the question of method and certainty at issue in Weisheipl’s fourth thesis. While the natural philosophy done by Aquinas and his contemporaries tended to proceed (or at least attempted to proceed) demonstratively and contemporary scientific methodology tends to proceed dialectically, natural philosophy itself does both. In other words, the difference between the two is merely apparent.

Beyond those three theses, however, the rest of the theses on Ashley’s list (1, 2, 3, 5, and 7) look more ad hoc. And in one important respect, they are. Unlike Weisheipl’s fourth thesis, which I argued above is a necessary consequence of his and Fernández-Alonso’s first thesis, there is no entailment relation between Ashley’s theses 1, 2, 3, 5, and 7 and the earlier commitments of the River Forest School. Nevertheless, they are connected. If the larger project of River Forest Thomism was to reemphasize the importance of natural philosophy as entirely distinct from metaphysics and as importantly connected with the natural sciences, it is easy to see how each of these theses contributes to that overarching goal.

Consider, for example, Ashley’s first, second, and fifth theses, which are hermeneutical in character. It is not hard to see how interpreting Aquinas as (a) a convinced Aristotelian (b), whose philosophy is best found in his commentaries on Aristotle and (c) whose natural philosophy should be interpreted in light of Aristotle’s logical works, would highlight the importance of natural philosophy. For (a) an Aristotelian Aquinas is more likely to emphasize natural philosophy than, say, a Neoplatonic Aquinas; (b) a large proportion of Aquinas’s Aristotelian commentaries are devoted to works on natural philosophy; and (c) interpreting Aquinas’s natural philosophy in light of Aristotle’s logical works means giving it the same methodological rigor that he gives to Christian theology and to metaphysics.

Something similar can be said about Ashley’s seventh and third theses, both of which are speculative in character. If natural philosophy provides the tools for resolving present-day scientific paradoxes, then we ought not to ignore natural philosophy. Likewise, if natural philosophy is a precondition (and not just pedagogically) for doing metaphysics, then no one interested in metaphysics can afford to ignore natural philosophy.

With respect to the historical self-understanding of the River Forest School, then, I think we need to divide Ashley’s eight theses into two groups. On the one hand, we have theses 4, 6, and 8, which are strongly connected to the theses articulated by Weisheipl and Fernández-Alonso. On the other hand, we have theses 1, 2, 3, 5, and 7, which are less strongly connected to the earlier theses, but which nevertheless contribute to the larger project of the school. I propose that we call the former the “core” theses and the latter the “ancillary” theses. We can then produce a table (

Table 1. River Forest Thomism after 90 Years.

Core Theses (1) The purely natural sciences are the parts of natural philosophy. (2) The mathematical sciences are not the parts of natural philosophy, though their subjects overlap. (3) Natural philosophy and metaphysics are distinct and autonomous sciences, with the former preceding the latter in the order of learning. (4) Natural philosophy admits of multiple stages of inquiry, each with its corresponding degree of certainty (i.e., it sometimes proceeds observationally, sometimes dialectically, sometimes demonstratively, etc.).

Ancillary Theses (5) Aristotelian natural philosophy provides the tools for resolving present-day scientific paradoxes. (6) Aquinas’s natural philosophy is best understood in light of Aristotle’s logical works. (7) Aquinas should be interpreted as a convinced Aristotelian. (8) Aquinas’s philosophy is best drawn from his commentaries on the works of Aristotle. (9) Aquinas’s order for learning the sciences is the same as the order for establishing the sciences, and thus metaphysics cannot be established without natural philosophy.

) that includes all the theses mentioned by Fernández-Alonso, Weisheipl, and Ashley, divided into two columns according to whether the thesis is core or ancillary:

With Table 1 in hand, we are now in a position to state clearly what was really at issue for the River Forest Thomists. The school should be identified with the core theses listed on the left-hand column. These are the constant commitments shared by its central figures and running throughout its entire history. If someone denies one of the first four theses on Table 1, that person is not a River Forest Thomist in the sense explicitly identified and expressed by the River Forest Thomists themselves. And if someone affirms the first four theses on Table 1, that person is a River Forest Thomist in that precise sense. It would be a mistake to take the ancillary theses on the right-hand column as definitive for the school’s historical self-understanding. That would be to lose the forest for the trees. And it would certainly be a mistake to take just one ancillary thesis as definitive for the school. That would be to lose the forest for a single tree.9

Unfortunately, that is precisely what many people have done. They have associated the River Forest School so strongly with thesis 9 on the chart above that they take it to be constitutive of the school itself: on this view, someone is a River Forest Thomist if and only if they affirm thesis 9 (see, for example, Dewan 2006; Klubertanz 1958; Knasas 2019, pp. 66–70; Long 2019, pp. 1112–14; Owens 1972; te Velde 2019, pp. 52–55; Wippel 2019, pp. 33–37). Even more unfortunately, this view has been endorsed both by thinkers who identify as River Forest Thomists and by thinkers who do not. As such, we should distinguish between River Forest Thomism—the actual historical school whose self-understanding over the course of 90 years is captured by the graded commitments expressed in the chart above—and “River Forest Thomism” (quotation marks to be read as scare-quotes), which is nothing more or less than an affirmation of thesis 9.

Since the core theses on the chart above are both true and methodologically important, all Thomists should be River Forest Thomists. The question that remains, however, is whether all Thomists should be “River Forest Thomists.” I maintain that they should not. To see why, we need to turn our attention from the forest to the tree.

3. The Tree

If the argument of the previous section is correct, then the particular thesis with which River Forest Thomism has come to be associated—and which constitutes what I have called, using scare-quotes, “River Forest Thomism”—is in fact an ancillary thesis. And it is an ancillary thesis in the precise etymological sense of the word. It is an ancilla-thesis, a handmaid thesis, a lady-in-waiting thesis. It is a thesis that undeniably seeks to be of service to her mistress, but which can also be dismissed from her presence at any time. And I maintain that this particular handmaid needs to be dismissed summarily. No matter how much it would prop up the proper pedagogical order, no matter how much it would defend the autonomy and integrity of natural philosophy, no matter how much it would catalyze inquiry into the proper relationship between natural philosophy and contemporary science; if ancillary thesis 9 on the chart above is simply not true, then it cannot render true service to the cause of River Forest Thomism. And it is not true.

3.1. Reasons for “River Forest Thomism”

Before considering arguments against ancillary thesis 9, however, we should begin by considering why someone would hold the thesis in the first place. As just noted, if the thesis were true, it would certainly contribute to the overall cause of River Forest Thomism—for it would make natural philosophy a strict requirement for any Thomist interested in doing metaphysics. But pragmatic reasons for wanting a thesis to be true are not theoretical reasons for affirming that thesis to be true. What, then, are the theoretical reasons invoked by adherents of ancillary thesis 9 in support of their position? At bottom, there are two: one is textual, the other is speculative.

The textual motivation for ancillary thesis 9 can be found in the first chapter of book 6 of Aristotle’s Metaphysics and in Aquinas’s commentary on that passage. There—in the context of distinguishing the three theoretical sciences of physics, mathematics, and first philosophy—Aristotle claims that if there were no separate (i.e., immaterial) substances, then physics would be first philosophy.10 And in his commentary on that passage, Aquinas seems to endorse Aristotle’s judgment.11 One reasonable interpretation of this passage is to understand Aristotle (and Aquinas) to be saying that until the existence of a separate substance has been demonstrated, it will be impossible for us to distinguish metaphysics from natural philosophy.12 And if we add the (also reasonable) assumption that, until we have distinguished metaphysics from natural philosophy, the only science in which a demonstration of the existence of immaterial substance can be given is the science of nature,13 then it will follow of necessity that metaphysics can only be established as a science by natural philosophy—i.e., ancillary thesis 9.

The speculative reason for affirming thesis 9 is this: for Aquinas, metaphysics is the science of what needs matter and motion neither in order to be nor in order to be understood; thus, to establish metaphysics as a distinct science, we must establish that there is something that needs matter and motion neither in order to be nor in order to be understood. Now, to establish that something does not need matter in order to be understood, all we have to do is check its concept for matter and motion. But more is required if we want to establish that such a thing does not need matter and motion in order to be. Whence comes our assurance of this existential possibility?

For the vast majority of the “River Forest Thomists,” we can be assured that something is possibly separate from matter and motion only when we know that something is actually separate from matter and motion—i.e., on the basis of a (natural philosophical) demonstration of the existence of an immaterial substance.14 Thus, in the absence of such a demonstration, we will never be in an epistemic position to affirm that there is something that needs matter and motion neither in order to be nor in order to be understood. Thus, metaphysics can only be established as a science by natural philosophy—i.e., ancillary thesis 9 is true.

Thus far, the tree. Now, why should we cut it down?

3.2. The Standard Arguments, Refined and Combined

I want to begin my critique of “River Forest Thomism” by presenting a refinement of what I take to be the two standard arguments against it in the literature. I call the first “the premise argument” and it is usually presented as follows: nothing can be contained in the conclusion of a demonstration that is not contained in the premises of that demonstration; but the notion of ‘being’ that appears in the conclusion of a natural philosophical demonstration for the existence of an immaterial being is a metaphysical notion of “being”; ergo, the notion of “being” that appears in the premises of natural philosophical demonstrations for the existence of an immaterial being must be a metaphysical notion of “being.” Therefore, the metaphysical notion of “being” is not something established by a natural philosophical demonstration (see, for example, Long 2019).

This argument is closely related to another argument, which I call “the equivocation argument.” It is usually presented as follows: if the metaphysical notion of “being” is established only on the basis of a natural philosophical demonstration of the existence of an immaterial being, then the notion of “being” employed in the premises of such an argument must be a non-metaphysical notion of “being”; but any argument that has a non-metaphysical notion of “being” in its premises and a metaphysical notion of “being” in its conclusion equivocates; therefore, if the metaphysical notion of “being” is established only on the basis of a natural philosophical demonstration of the existence of an immaterial being, then natural philosophical demonstrations of the existence of an immaterial being equivocate; but no equivocal argument is valid; therefore, if the metaphysical notion of “being” is established only on the basis of a natural philosophical demonstration of the existence of an immaterial being, then the metaphysical notion of “being” cannot be established.

I think these two arguments can be refined and combined. This refinement takes the form of connecting them more explicitly with the idea that metaphysics is about what needs matter and motion neither in order to be nor in order to be understood. The combination occurs in the form of a disjunctive argument, as follows:

The Standard Objections, Refined and Combined

(1)

The notion of “being” employed in natural philosophy is either (a) compatible with immaterial existence or (b) incompatible with immaterial existence.

(2)

If (b), then natural philosophy cannot—in principle—prove the existence of an immaterial being.

(3)

If (a), then natural philosophy’s proofs for the existence of an immaterial being presuppose, rather than establish, the fact that being can be immaterial.

(4)

Natural philosophy can—in principle—prove the existence of an immaterial being.

(5)

Ergo, natural philosophy’s proofs for the existence of an immaterial being presuppose, rather than establish, the fact that being can be immaterial.

Since (a) and (b) in premise (1) are contradictories and no category mistake is involved, it is hard to see how someone could object to premise (1). The equivocation argument proves premise (2). The premise argument proves premise (3). And, at least to my knowledge, all parties involved in the debate grant premise (4).15 As such, this refined argument looks like it supplies a strong reason to reject ancillary thesis 9.

I do, however, have a worry about the premise argument (and so about the third premise in the refined argument just given). My worry is that the premise argument might involve an equivocation between epistemic modality and ontological modality. In particular, I worry about the inference we are supposed to make from (a), the fact that the notion of “being” employed in the premises of our natural philosophical proofs is compatible with immaterial existence, to (b) the fact that (a) is presupposed by those proofs. It seems plausible to me that the compatibility claim in (a) belongs to the domain of ontological modality, while the presupposition claim in (b) belongs to the domain of epistemic possibility.

An example might help illustrate my worry. Imagine someone who has only ever seen scalene and isosceles triangles and is unsure whether equilateral triangles are possible but is otherwise good at geometry. You then walk them through a proof that runs as follows: for any three angles that sum to 180°, there is a triangle that has those as its three angles; 60° + 60° + 60° = 180°; therefore, there is a triangle for which all angles are 60°; but if the angles are the same, then the length of the sides must be the same; therefore, there is a triangle for which all three sides are of the same length; therefore, equilateral triangles are possible.

It is clear that the notion of a “triangle” employed in the premises of this proof is compatible with having sides of equal length. But it does not seem true to say that this compatibility is presupposed by the proof, since the geometer in question genuinely does not know whether the notion of a “triangle” is thusly compatible until the proof is complete. In other words, at the beginning of the proof, it is epistemically possible that triangularity will turn out to be incompatible with having sides of equal length, even if it is not mathematically possible for triangularity to be incompatible with having sides of equal length.

Something similar might be said in objection to premise (3) in the refined argument given above: yes, the notion of “being” employed in the premises of natural philosophical demonstrations for the existence of an immaterial being is (as a matter of fact) compatible with immaterial existence, but this does not mean that we are presupposing such compatibility when engaged in such proofs. Until the conclusion is drawn, it remains epistemically possible that the notion of “being” employed in the premises will turn out to be incompatible with existing immaterially. And it is only when that epistemic possibility is closed off that metaphysics has been established as a science, or so I can imagine a “River Forest Thomist” saying.16

3.3. The Insufficiency Argument

Though I am not convinced that the objection just given on behalf of “River Forest Thomism” actually works, it does undermine my confidence in the standard arguments against it. But I am also not convinced that these standard arguments, either in their original forms or in their refined and revised form, are the best arguments against “River Forest Thomism.” As such, I would like to offer three further arguments to roughly the same conclusion. To the best of my knowledge, all of these arguments are novel. The first, which I call “the insufficiency argument,” goes like this:

The Insufficiency Argument

(1)

If most “River Forest Thomists” are right, then demonstrating the existence of God is sufficient to establish the science of metaphysics.

(2)

Demonstrating the existence of God is not sufficient to establish the science of metaphysics.

(3)

Therefore, most “River Forest Thomists” are wrong.

The first premise of this argument is true as a matter of historical fact. While “River Forest Thomists” allow for the possibility that metaphysics can be established as a science by demonstrating the existence of an immaterial being other than God (e.g., by demonstrating the existence of an angel or by demonstrating the continued existence of the human soul after death), primacy of place has always been given to proofs of God’s existence. Perhaps there is, somewhere out there, a “River Forest Thomist” who insists that metaphysics can only be established by demonstrating the existence of a created immaterial being. But I have never met one. And I doubt I ever will.

But surely it is premise (2), not premise (1), that the “River Forest Thomist” will object to. So, why should we think that demonstrating the existence of God is not sufficient to establish the science of metaphysics? The proof is actually very simple:

Proof of Premise (2)

(1)

Demonstrating the existence of something outside the subject-matter of metaphysics is not sufficient to establish the science of metaphysics.

(2)

God is outside the subject-matter of metaphysics.

(3)

Demonstrating the existence of God is not sufficient to establish the science of metaphysics.

Suppose that Jack is in doubt about whether there “are” mathematical objects—even in the thin sense of “there are” that is required to establish that mathematics has a subject-matter. Now imagine that Jill, purportedly coming to his aid, offers Jack a proof of the post-mortem existence of the human soul. When Jack’s brow furrows in confusion and his head tilts with bewilderment, they will do so with good reason. Again, suppose that Jill is in doubt about whether there are any genuinely non-sensory organisms—i.e., about the subject-matter of (Aristotelian) botany—and Jack offers her a proof of the existence of numbers. Surely Jill’s brow will have as much reason to furrow, and her head as much reason to tilt, as did Jack’s in the previous scenario. Again, suppose that Titius is in doubt about the subject-matter of virtue ethics—perhaps he has just learned, and is now tempted by, some meta-ethical error theory—and Bertha “rides again” to his aid with a demonstration of the existence of plants.17 Poor Titius may well acquire a furrowed brow like Jack’s and a tilted head like Jill’s, but he will surely not acquire confidence that virtue ethics is a legitimate discipline.

The general lesson to be drawn from all these examples is that proving the existence of something outside the subject-matter of a given science does not establish the existence of the subject-matter of that science. Thus, by application of the general to the particular, proving the existence of something outside the subject-matter of metaphysics does not establish the existence of the subject-matter of metaphysics. And that is precisely what the first premise in the proof above states. Thus, if God is outside the subject-matter of the science of metaphysics, then proving the existence of God will not suffice to establish the science of metaphysics.

So, is God outside the subject-matter of Thomistic metaphysics? There are a few twentieth-century Thomists who would say that the answer is no.18 But every single “River Forest Thomist” that I am aware of would say that the answer is yes. It is yes according to Ashley (See Ashley 2006, p. 139), yes according to Wallace (See Wallace 1977, p. 121), yes according to O’Brien (See O’Brien 1960, passim, but especially pp. 22–33, 50–54, 124–69), and yes according to Doig (See Doig 1972, pp. 378–80). But most importantly, the answer is yes according to Aquinas himself. For St. Thomas is explicit that (a) ens divinum does not fall under ens commune, and (b) the subject-matter of metaphysics is ens commune. Thus, ens divinum does not fall under the subject-matter of metaphysics.19

This is not a minor point.20 It is something that distinguishes Aquinas from towering figures who came before him (like Avicenna), towering figures of his own day (like Siger of Brabant), and towering figures who were yet-to-come (like Scotus). Aquinas’s decision to limit the subject-matter of metaphysics to ens commune, rather than to extend it to a notion of ens that would encompass both God and creatures (whether univocally or analogically) was pivotal both for the apophatic character of his natural theology and for the scientific character of his ontology. With respect to the former, it made possible Aquinas’s wholehearted endorsement of the Dionysian-Neoplatonic claim that God is rightly and truly said to be “beyond being.” With respect to the latter, it made possible Aquinas’s wholehearted endorsement of Aristotle’s claim in Metaphysics IV, c. 1, that one of the central tasks of the science of metaphysics is to seek the principles and causes of being itself. For unless the being that constitutes the subject-matter of metaphysics is posterior to and caused by God, it will be impossible to say of such being either that God is beyond it or that it has principles and causes.

What does all of this mean, for present purposes? It means that while demonstrations of God’s existence do indeed prove that there is an actually immaterial being in the analogical sense according to which “being” can be predicated of the principle and cause of ens commune, such demonstrations do not prove that there is an actually immaterial being in the analogical sense of “being” that corresponds to ens commune itself. And this means that no demonstration of God’s existence will ground the judgment that ens commune does not need matter and motion in order to be. This is a problem for “River Forest Thomism” because it is ens commune, not God, that constitutes the subject-matter of Thomistic metaphysics. Thus, no demonstration of God’s existence can ground the judgment that the subject-matter of metaphysics does not need matter and motion in order to be. In other words, no demonstration of God’s existence can establish the science of metaphysics.

Before moving on to my second novel argument against “River Forest Thomism,” I want to take a moment to make one further observation related to the previous line of criticism. The insufficiency argument aims to show that the “River Forest Thomist’s” epistemic/modal requirement—i.e., the requirement that we ground our knowledge of the possible immateriality of being in a demonstration of the actual immateriality of being—is simply too demanding a requirement. It does so “from the top down” as it were, by pointing out that demonstrations of the existence of God—the demonstrations most commonly appealed to—cannot deliver the hoped-for result. If the epistemic/modal requirement is to be met, it must be met by, e.g., demonstrating the existence of angels or of immortal souls.

But we can make a similar criticism “from the bottom up” as well. If the reasoning behind the epistemic/modal requirement is right, then it proves not just that our knowledge of the possible immateriality of being needs to be grounded in a demonstration of the actual immateriality of being, but it also proves that our knowledge of the possible immateriality of substance needs to be grounded in a demonstration of the actual immateriality of substance, that our knowledge of the possible immateriality of accidents needs to be grounded in a demonstration of the actual immateriality of accidents, that our knowledge of the possible immateriality of potency needs to be grounded in a demonstration of the actual immateriality of potency, that our knowledge of the possible immateriality of form needs to be grounded in a demonstration of the actual immateriality of form, and so on for every properly metaphysical ratio. Consistent application of the reasoning behind the epistemic/modal requirement, then, entails that when the “River Forest Thomist” establishes the science of metaphysics, what he has established will be spectacularly anemic.

To see why this is so, consider an example. Imagine a “River Forest Thomist” who establishes the science of metaphysics by demonstrating the immortality of the rational soul. Since the soul thus demonstrated is a being and a form, he will be entitled (at least by his own lights) to claim that being, form, and soul can be numbered among the things that need matter and motion neither in order to be nor in order to be understood. But the separated soul that has just been demonstrated to exist is neither a substance, nor a potency, nor an accident, nor a whole, nor a perfectum, nor a multiplicity, etc. Thus, the “River Forest Thomist” will have to wait until he has further demonstrations of the actual immateriality of each of these things before he can number them among the things that need matter and motion neither in order to be nor in order to be understood. This epistemic/modal requirement is simply too strong. On the one hand, it cannot be satisfied by demonstrations of the existence of God—which all parties acknowledge to be among the strongest arguments for positively immaterial beings. On the other hand, if it is satisfied by the demonstration of something that falls under ens commune, the “metaphysics” thus established turns out to be significantly truncated. Something has gone wrong.

3.4. The Counterfactual Materialism Argument

The second novel argument I want to propose against “River Forest Thomism” (i.e., ancillary thesis 9) bears upon the counterfactual supposition of materialism that lies at the heart of the textual motivation for that thesis (by “materialism,” here, I mean the view that all beings are material beings). Recall that in Metaphysics VI, c. 1, Aristotle says that if there were no separate substances, then physics would be first philosophy. And the “River Forest Thomists” interpret this to mean that it is only by demonstrating the actual existence of an immaterial being that we can be secure in our judgment of the possible existence of an immaterial being. Prior to such a demonstration, physics will be indistinguishable from metaphysics. In other words, “River Forest Thomists” regularly defend ancillary thesis 9 with the following line of reasoning: Aquinas follows Aristotle in affirming that if (counterfactually) materialism were true—i.e., if (counterfactually) all beings were material beings—then there would be no difference between physics and metaphysics; by contraposition, then, unless materialism is false—i.e., unless not all beings are material beings—metaphysics and physics will be indistinguishable; thus, in order to distinguish metaphysics from physics, we first have to prove that there are, in fact, immaterial beings. And since such a proof will have to belong to physics, it follows that ancillary thesis 9 is true—i.e., physics must be prior to metaphysics not only in the order of learning, but also in the very establishment of the sciences themselves.

But there is a serious problem with this view. To see why, consider the following argument:

The Counterfactual Materialism Argument

(1)

If most “River Forest Thomists” are right, then, on the supposition of materialism, physics would be indistinguishable from metaphysics.

(2)

But on the supposition of materialism, metaphysics would be indistinguishable from mathematics.

(3)

Thus, if most “River Forest Thomists” were right, then, on the supposition of materialism, physics would be indistinguishable from mathematics.

(4)

But on the supposition of materialism, physics would not be indistinguishable from mathematics.

(5)

Therefore, most “River Forest Thomists” are wrong.

The only premise in this argument that a defender of ancillary thesis 9 can or should want to object to is premise (2). But objecting to premise (2) is extremely difficult, since it admits of fairly straightforward proof:

Proof of Premise (2)

(1)

If most “River Forest Thomists” were right, then, on the supposition of materialism, all the items ordinarily identified as metaphysical would need matter and motion in order to be.

(2)

But, on the supposition of materialism, all of the items ordinarily identified as metaphysical would not need matter and motion in order to be understood.

(3)

Thus, on the supposition of materialism, all the items ordinarily identified as metaphysical would need matter and motion in order to be but not in order to be understood.

(4)

Mathematics is the science of what needs matter and motion in order to be but not in order to be understood.

(5)

Therefore, if most “River Forest Thomists” were right, then metaphysics would be indistinguishable from mathematics.

The first premise in this proof does nothing more than (a) explain what the counterfactual supposition of materialism amounts to and (b) identify that supposition as part of how “River Forest Thomism” understands ancillary thesis 9. The second premise points to something that no adherent of that thesis should want to object to, namely, the fact that our judgment of whether something needs matter and motion in order to be understood is independent of our judgment of whether something needs matter and motion in order to be. As we have already seen in Section 3.1, that distinction motivates the “River Forest Thomist’s” epistemic/modal requirement that our knowledge of the possibility of an immaterial being be grounded in a demonstration of the actuality of an immaterial being. And since the supposition of materialism bears upon the necessity of matter and motion in order to be, rather than in order to be understood, it follows that the independence of metaphysical items in thought will remain unchanged, regardless of whether materialism is supposed or not. (3) follows from (1) and (2). And (4) is Aquinas’s explicit teaching in the commentary on Boethius’s De Trinitate—a teaching affirmed by all “River Forest Thomists.”21 Finally, (5) follows from (3) and (4), at least on the plausible assumption that two sciences are indistinguishable if all the items ordinarily identified as belonging to those sciences share the same speculative formality.

What the counterfactual materialism argument shows is that “River Forest Thomism” ends up pitting two of Aquinas’s texts against one another. On the one hand, we have Aquinas’s teaching in q. 4 of his commentary on Boethius’s De Trinitate regarding the formal objects of physics, mathematics, and metaphysics. On the other hand, we have Aquinas’s endorsement of Aristotle’s claim that if there were no separate substances, physics would be first philosophy. When the latter is interpreted through ancillary thesis 9—i.e., as a claim about the need for natural philosophy to establish the science of metaphysics by means of a demonstration of an actually immaterial being—these two texts become incompatible. For the logic of the first text requires that, on the supposition of materialism, metaphysics would be indistinguishable from mathematics. But the interpretation of the second text through ancillary thesis 9 requires that, on the supposition of materialism, metaphysics would be indistinguishable from natural philosophy. Since both cannot be the case, I submit that it is ancillary thesis 9—and so “River Forest Thomism”—that ought to go.

3.5. The Cumulative Argument

The final argument I want to offer against “River Forest Thomism” is what I call the “cumulative argument.” It is cumulative in the sense that it builds upon the previous two arguments. It is also stronger than the previous two arguments—at least with respect to its scope. Where the insufficiency argument and the counterfactual materialism argument both lead to the conclusion that most “River Forest Thomists” are wrong—and so leave open the possibility that some “River Forest Thomists” might remain unaffected by the argument—the cumulative argument leads to the conclusion that no Thomist should be a “River Forest Thomist.” The argument goes like this:

The Cumulative Argument

(1)

To be a “River Forest Thomist” (at least consistently), one must hold that (a) were there no actual immaterial beings, metaphysics would be indistinguishable from mathematics, (b) natural philosophical demonstrations of God are not sufficient to distinguish metaphysics from mathematics, and (c) natural philosophical demonstrations of created immaterial realities only establish the science of metaphysics vis-à-vis precisely what has been concluded by the demonstration in question (e.g., vis-à-vis form, if an immaterial form has been demonstrated, vis-à-vis substance, if an immaterial substance has been demonstrated, etc.).

(2)

But no Thomist should hold (a), (b), and (c).

(3)

Therefore, no Thomist should be a “River Forest Thomist.”

With respect to the first premise, (a) is the conclusion of the proof of premise (2) in Section 3.4, above, (b) is the conclusion of the proof of premise (2) in Section 3.3, above, and (c) is another way of stating the conclusion of the final observation made at the end of Section 3.3. Thus, anyone who accepts the argumentation of the article thus far ought to accept premise (1). Premise (2) strikes me as almost self-evident, but I do think I can offer some further argumentation in its favor. As noted in Section 3.3, the only reason one could have for holding (b) and (c) together is antecedent commitment to what we have been calling the “epistemic/modal requirement” (i.e., the requirement that our knowledge of the possibility of something immaterial must be grounded in a demonstration of the actuality of something immaterial). But that requirement seems wrong. For if it were true, it would either be true because it is a particular instance of a more generally true principle that “our knowledge of the possibility of some x must be grounded in a demonstration of the actuality of some x”, or it would be true because there is something special about immateriality that makes this not-generally-true principle true in this case. But there does not seem to be anything special about immateriality, and the general principle seems to be false. After all, we know that some organisms (e.g., methanogens) could live on Mars, even though we do not know whether any organisms actually live on Mars; we know that the world could have been without a beginning in time, even though we know that it is not actually without a beginning in time; we know that God could make himself sacramentally present under the species of rice, even though we have good reason to think that he never has and never will actually do so; and so on, and so forth. Thus, no Thomist should hold (b) and (c) together. A fortiori, no Thomist should hold (a), (b), and (c) together. In other words, no Thomist should be a “River Forest Thomist.”

4. Losing the Forest for the Tree

I want to end this article with a plea. We must not lose the forest for the trees. In particular, we must not lose the forest for a single tree. Far too much attention has been given to “River Forest Thomism” and not nearly enough attention has been given to River Forest Thomism. Contemporary philosophers in both the analytic and continental traditions have lost almost all understanding of—and so, by extension, almost all appreciation for—natural philosophy as an integral and autonomous discipline. Moreover, as already noted in Section 2, many of the themes considered central to contemporary metaphysics are actually topics proper to natural philosophy. Further still, many of the central questions in contemporary philosophy of science concern what role mathematics plays in and what effects mathematics have upon scientific practice. For example, do mathematical models tell us anything real about the natural world, or are they purely heuristic devices? Again, are mathematical models necessary for doing “hard” science, or can natural scientists do without them? Questions like these are closely connected to core theses 1 and 2 of River Forest Thomism, and they cannot be answered without a thorough understanding both of contemporary scientific theory and of contemporary scientific practice. As such, a renewal of River Forest Thomism would encourage Thomists to enter into dialogue not only with analytic metaphysicians and contemporary philosophers of science, but also with natural scientists themselves.

What would such a renewal of River Forest Thomism look like? While it is impossible to say with precision, I do think its four core theses allow us to predict at least some of the concrete effects we would see. Core thesis 3 would ensure that far fewer of tomorrow’s Thomists “skip over” natural philosophy, diving straight into metaphysics or theology (as so many Thomists have being doing for the last 200 years). Core thesis 1 would ensure that tomorrow’s Thomists recognize the profound connection between the natural philosophy that would be so integral to their intellectual formation and the constantly developing panoply of contemporary natural sciences. Core thesis 4 would ensure that tomorrow’s Thomists have a much deeper appreciation of, and sensitivity to, the diverse methodologies that can be, have been, and are currently, employed in both natural philosophy and the natural sciences (since the latter are genuine parts of the former). Finally, core thesis 2 would protect tomorrow’s Thomists from naivety about the use of mathematics in the natural sciences and—by extension—other fields of study as well.

I am not only convinced that all four of the core theses of River Forest Thomism are true, but also that they ought to be uncontroversially true for anyone who is well-versed in Aquinas’s philosophical methodology and division of the sciences. As such, I think there should be little-to-no debate about whether all Thomists should be River Forest Thomists—they should. But even if I am being naïve about the uncontroversial nature of River Forest Thomism’s four core theses, I am not being naïve when I say that an intra-Thomist debate about those four core theses would be much more valuable than further debate about ancillary thesis 9. For a serious debate about River Forest Thomism (rather than “River Forest Thomism”) will have the effect of pushing Thomism beyond its usual boundaries and encouraging new conversations between Thomists, scientists, philosophers of science, and contemporary metaphysicians. This is not to say that the debate over “River Forest Thomism” is unimportant—after all, Section 3 of the present article was dedicated to that very task. But it is to say that there is a far more profitable debate to be had. And hopefully this article will contribute to that.