The following is from the introduction I give in my metaphysics course, last taught at the University of St. Thomas (TX) in Spring of 2016. It explains the germ of my Thomism as well as my rejection of modernism… in terms of metaphysics, at least.
There are few topics which seem more unsuited to the 21st century university than that of metaphysics: that is, the study of “being as being.” The subject is impossibly vague; the claims it makes seem inescapably representative of opinion rather than fact; it is an impractical field of study, advancing no discernable good for those that undertake its study. At best, it is seen as facilitating an ability for critical thinking or deconstructive analysis of arguments; but metaphysics as a science—as a real, substantive, revelatory process of human inquiry—is a mere pipe dream of religious academicians or would-be gnostic know-it-alls. Metaphysics is impractical. Metaphysics serves no purpose. Studying metaphysics will not move you one iota closer to a better job, to a more diversified skillset, to a higher earning potential.
This introduction might just as well be titled “Why study philosophy at all?” For while there are many schools of philosophical thought which strive to make it applicable to contemporary life, most of these schools do so only by aping the methods and goals of modern day empiriometric sciences (which interpret the world through quantification of things insofar as they can be observed by the senses), and with considerably less certitude or resulting progress. Oftentimes, the contemporary university attempts to relegate philosophical study to the category of “mental training”—it makes one better at critical thinking, at reasoning, at arguing, but does not actually teach anything; it trains you to think, but does not give you any answers.
Attempting to answer the question we are here considering—the question of “why study philosophy?”—is nothing new. Answers have been proposed for thousands of years, many of them both compelling and true. For instance, it may be said that empiriometric science cannot provide all of the answers: this is true. It may be said that philosophy will sharpen your intellect: this is also true. It may be said that the unexamined life is not worth living: again, true. It may be said that philosophy is the highest pursuit of natural reason: true. But what is common to all of these answers and yet expressed fully by none of them is this: philosophy alone, among those things which are provided to us as possible by our natural abilities and circumstance—and especially metaphysics, which is the summit of philosophical inquiry—fulfills our most fundamental human need.
This message will be rejected by the contemporary sentiment that love is primary among human needs; that human beings most desire and attain fulfillment in loving and being loved. This sentiment is not false, but it is misplaced, and does, so to speak, put the cart before the horse. Without love, human beings live an impoverished and unfulfilling life, truly. But to love, one must first know; we cannot love rightly that which we do not know, and we cannot have knowledge through love alone. Any impulse towards something not known, any appreciation of or desire for something which is not understood is not a complete human love, but merely animal eros; that is, an operation of corporeal desire. Many may think that all our desires are merely corporeal; many may think that all of our knowledge is merely a result of operations occurring within the brain, however little we may yet understand its functions, and that empiriometric science will eventually be able to explain all our thoughts and desires, and indeed, all the universe. Neuroscientists and biological psychologists have recently attempted explanations of even love in terms of a purely chemical analysis, reducing explanation of it to adrenaline, dopamine, and oxytocin
Yet if this materialist account of reality can be shown to be false, from clear and undeniable reasons—if human beings have some operation which transcends the operations of corporeal organs, discernable through reflection, if knowledge of the natural world itself cannot reduce to what is discerned through empiriometric study—then we must, if we are to remain intellectually honest, ask “What else is there? How can we know it?” We must, at the very least, admit the possibility of a supersensible reality: and in the pursuits of increasing our knowledge and deepening our ability to love, in pursuing genuine human happiness and a life well-lived, we must investigate this possibility.
In a sense, the quarry of our pursuit is everything. Metaphysics, as a study, has no boundaries. That is a big claim, undoubtedly. But it is justly made, because we are here, today, in pursuit of the truth. That is, we are trying to figure out what is; what really is, how we know what is, how we know reality, how we argue for reality, and how a knowledge of that reality not only informs but also improves our lives—or at the very least, how it can.
The Situation of Metaphysics in the 21st Century
There are many things which can cause a Thomistic philosopher to grit his teeth in the 21st century, though it is likely that a great many Thomistic philosophers—that is, the philosophers who take their principles from Thomas Aquinas—have been gritting their teeth about a great many things, over many centuries… likely since the great thinker himself exited this life. One of the contemporary bruxism-inducing offenses to the Thomist is the reduction of philosophy to the sphere of opinion; many teeth (at least, those belonging to the author) practically shatter at the utterance “my personal philosophy”. In the time of St. Thomas, and for centuries after him and millennia before, philosophy was not something held personally, as a mere opinion or something purely subjective. Rather, it was a science, though one which was admittedly more disputed as to its foundations than, say, modern biology or quantum physics. Nevertheless, while it operates differently from what are generally considered sciences today, philosophy is not, nor could it ever be, a mere matter of opinion. To the good Thomist’s ears, “my personal philosophy” sounds just as absurd as “my personal nuclear thermodynamics” or “my personal mathematics”. That philosophy has come to be viewed by many as a “subjective” interpretation of the world is due in large part to a period of philosophical inquiry, spanning roughly four centuries, which lauded originality over consistency, divided the material from the spiritual, and made the theoretical subservient to the practical.
This period of philosophy, called modern, is generally agreed to have begun in 1641 A.D., when Rene Descartes published his Latin manuscript, Meditationes de prima philosophia, in qua Dei existentia et animae immortalitas demonstratur—Meditations on First Philosophy: in which the existence of God and the immortality of the soul are demonstrated (though one could also argue it began in 1637 A.D., with the publication of the Discourse on Method). In many ways, this seems, to glance at the title, a continuation of the metaphysics practiced among the schoolmen, i.e., the scholastics of the previous several centuries, a body of men generally constituted by monks (such as those of the Benedictine order) and friars (as the Dominicans and Franciscans), which metaphysics was largely based upon the work of Aristotle. “First philosophy”—prima philosophia—was another name commonly used for metaphysics, the study of “being as being”, which typically concludes with, or includes at some point, any number of proofs for the existence of God as the first principle of all being. Metaphysics has in many cases been identified with philosophy itself, or at the very least said to be its pinnacle. It was “first” philosophy not because it was the original philosophical thought, but because of its preeminence. And yet, Descartes’ Meditations, though ostensibly conceived within the same vein of the traditional metaphysics of the schools, turned the whole project of metaphysics inside out. The reality of things outside the mind—res extra animam—is not taken for granted in the Cartesian project: for such things are seemingly known by sense perceptions, and the senses may be deceived, their objects can be discontinguous, dreams may be mistaken for reality, illusions or mirages may appear as genuine beings, and there is a certain relativity in the perception of things such as heat or cold.
Establishing as his criterion for the veracity of any belief that it be clear and distinct—such as the sort of precision which is found in mathematics—and that anything which can be subjected to doubt cannot be taken for certain, Descartes subsequently attempts to prove the existence of God before he proves the existence of any other things, starting with what he feels is the one clear and distinct idea which cannot be subjected to any doubt whatsoever: namely, the infamous “I think therefore I am”, cogito ergo sum. Thus, he sought not simply to revamp first philosophy, but all philosophy; rather than ask “What is it that we know?” or “How do we know these things?” he asked “How can we know anything at all?” While this might seem a logical starting place, we shall eventually see that it is an untenable one, which dooms all of its faithful adherents to an unphilosophical life.
Descartes seemingly had noble intentions—he was, in fact, principally concerned with providing a solid foundation for all knowledge. Moreover, many of the schoolmen of his day were not known for teaching metaphysics with vigor or clarity, and a revitalization of the philosophical discipline was, in much of Europe (the Iberian peninsula being the sole exception), required.
Unfortunately, his endeavors threw the majority of philosophical inquiries into a quagmire from which the discipline as a whole would not successfully emerge for nearly 400 years. For generations, philosophers fought tooth and nail over whether or not our ideas of things arose from some immaterial medium (i.e., through some purely spiritual process, either internal or external to our minds) or were derived solely from empirical observation (i.e., from sense impressions). What neither side realized was that both shared in a fatal assumption—the assumption that the ideas themselves are the direct objects of knowledge. Indeed, this unacknowledged common assumption ultimately reduced both sides to the same position. The empiricists were really idealists. Consequently, both sides of the dispute were eminently concerned with how we justify the relating of the immediately known, our ideas, to those which are mediately made known by those ideas, things. Indeed, in many ways, the effects of this philosophical inversion—moving from thought to things instead of the other way around—are still felt: the tradition of analytic philosophy (consciously or not) still operates within the basic Cartesian framework, and both the phenomenological tradition and the neo-scholastic traditions are often preoccupied with overcoming this “critical” turn—the examination of the apparatus of knowledge as a prerequisite to any other inquiry—oftentimes to their own detriment.
These latter two schools are often termed “realist”, for they maintain that the objects of our understanding are not the ideas themselves, but rather that the ideas are the means by which we have an immediate understanding of things outside the mind, the so-called real. Thus, a dichotomy has been advanced between idealism and realism, and much philosophy of the past century has been carried out through their opposition to one another. Nevertheless, realism, though far superior to the idealism of modernity, has its own set of problems, not the least of which is the meaning of the word “real.” Before those problems can be addressed, however, the controversy itself must be unfolded.
The primary antagonist in the battle of realist philosophies versus the critical philosophy or “turn to the ideas” characteristic of the moderns has been Immanuel Kant. This 18th century German philosopher sought to solve the contention between the idealist philosophers—who, following Descartes, asserted that ideas are not derived from the material or sensible world, but are either somehow innate or come from immaterial principles outside the soul—and the empiricist philosophers—who asserted that all ideas are derived from our sense impressions. The method which Kant proposed was termed, by Kant himself, either transcendental or critical idealism. What he desired to find, like the others before him stretching back to Descartes, was an absolute certainty for our knowledge, towards which he had been prompted by reading the English empiricist, David Hume, who contended that we could not really know any “matters of fact”, i.e., anything concerning the world outside our own ideas, but could consider them only with probability. In order to find a certitude which overcomes this mere probability, Kant said that we must have necessity in our judgments; in other words, that the content contained in the judgment cannot be otherwise, and this indubitability can only be based on that through which the judgment is made; i.e., the faculties of the individual making the judgment must have an a priori necessity, a necessity which in no way depends upon experience. To this end, he developed a remarkably complex system to explain how such judgments are made.
What results from this system, however, is not any knowledge of things in themselves, but only things inasmuch as they appear to us. Thus, anything to which we can give a name or a description is not actually given to that thing as it exists outside the mind, but only as it appears to us within our minds. (This knowledge of mere appearances is called phenomenalism, as opposed to the knowledge of things through their appearances advocated by many phenomenologists, both terms deriving from the Greek word phaeinomena, meaning “appearance”.) For Kant, therefore, a strict certitude belongs to knowledge of mathematical objects, and ultimately to the knowledge of the structures of knowledge itself, but only a loose or relative certitude is found in knowledge of the extramental, insofar as sense experience continues to verify our judgments of appearances. Consequently, anything of which we cannot have sense experience, or which cannot be verified through sense experience, is something he says that we cannot know at all—and so metaphysics is not merely a disputed science, but an impossible science. Acceptance of this position towards the unknowability of things which cannot be verified by sense experience has not only relegated metaphysics and much of philosophy to sphere of unreasoned belief, but has also introduced a fictional chasm between reason and faith.
Much has been done, however, by both phenomenologists and Thomists to refute this Kantian “critical idealism” and therefore to restore metaphysics and a metaphysical philosophy to its place within an academic course of study—and we shall here pursue an understanding developed both by Thomas himself as well as some later-day Thomists, a position which we might denominate “moderate Thomistic realism.” Such an understanding, however, is very foreign to the modern methods of education, science, and popular opinion, which are gleaned more from the modern period of philosophy than the scholastic, and consequently, such an understanding may seem very unusual for the readers who are many centuries removed from its origin, from its language, and from its cultural context. As such, it is quite helpful to study the moderns first—particularly Hume and Kant—in order to show their philosophical deficiencies, and therefore to evitate many of the contemporary scruples about the justifiability of metaphysical inquiry. Only then can we turn our full attention to the wisdom of Thomas.
A Succinct Account of the Humean Qualm
In order to see precisely how and why it is that Kant arrives at his conclusion—i.e., for what reasons he states metaphysics to be impossible—we ought to start with the context in which he was writing.
Descartes’ Meditations, along with his Discourse on Method, as the foundations of a theory of knowledge radically different from the seemingly-theologically-entrenched epistemology espoused by the scholastics, had profoundly affected the intelligentsia of 17th and 18th century Europe; not, however, as a theory ubiquitously accepted and agreed upon, but rather as the instigation of a great debate, one in which all of the participants largely if not entirely ignored the work of scholasticism. Familiar with Descartes’ work, the English philosopher John Locke wrote a rather sizeable treatise dealing with the newfound problem of knowledge, titled An Essay Concerning Human Understanding, which expounded an alternative theory as to how man knows, one in which we do not start with the thoughts “I think” or “I am” as the foundation of certitude, but rather with our sense impressions. Innate ideas were unequivocally rejected by Locke; to suppose anything being in the mind from birth, he said, of which one is unconscious, involves a contradiction. In other words, everything which is in our minds, according to Locke, is something of which we are conscious. Rather, Locke says, everything we know is from our sense experiences.
While this is similar to the methodology of realist approaches to knowledge, inasmuch as it accepts a real change in the sense powers which is affected by sensible things as the starting point of knowledge, Locke, like Descartes, shared in the assumption that the ideas of our sense impressions (and those ideas of our own operations derived from reflection upon the ideas of our sense impressions—such as the actions of the mind and the passions arising therein) are the direct termini of our acts of knowing, rather than those things which caused the impression to be made, that we do not directly know the things sensed, but the ideas they cause in us. This empirical-idealism, or sense impression-based idealist epistemology, depended largely upon the distinction of two kinds of sense qualities, i.e., the power in objects of sensation to produce in us their correspondent ideas: primary qualities—figure (shape), extension, motion, rest, number, and solidity—and secondary qualities—all colors, sounds, smells, and tastes. Locke posited that the secondary qualities were understood or determined subjectively, that is, within the individual sensing, whereas the primary qualities were proper to the things themselves, and independent of all observation, such that the ideas whereby we know primary qualities are accurate reflections of those things as they are in themselves:
The ideas of primary qualities of bodies are resemblances of them, and their patterns do really exist in the bodies themselves, but the ideas produced in us by these secondary qualities have no resemblance of them at all. There is nothing like our ideas, existing in the bodies themselves. They are, in the bodies we denominate from them, only a power to produce those sensations in us: and what is sweet, blue, or warm in idea, is but the certain bulk, figure, and motion of the insensible parts, in the bodies themselves, which we call so.
In other words, what we signify by the ideas of secondary qualities are not representations of the reality of things, but only a “power”—that is, some sort of cause—found in the thing which is able to produce in us, by means of the observed primary qualities, those secondary ideas. Thus, the ideas of primary qualities represent what is commonly today said to be objective, i.e., actually present in some extra-mental reality. The reality of these “objective” things was thought to be certain—for while there can be disagreement or deception with regard to a thing’s color or taste, its solidity, as verified by the sense of touch, seems indisputable, and from there, one can judge of a thing’s motion or rest, extension or motion.
Along with Descartes, though in many ways his opposite, Locke may be considered one of the founders of modern philosophy and its typical “way of ideas.”
Following Locke in the empiricist tradition, albeit in an unusual way, is George Berkeley, a Bishop of the Church of England. Bishop Berkeley’s two most famous works, the Treatise Concerning the Principles of Human Knowledge and the Three Dialogues between Hylas and Philonous, advocated a position in which all sense perception belonged to the category Locke called secondary. As he pointed out, contra Locke, one cannot conceive of a primary sense quality without attendant secondary qualities: every perceived thing possessing a shape, extension, motion, rest, solidity, or number must necessarily be conceived along with at least one secondary quality.
Thus we come to David Hume. Though an empiricist, Hume was also something of a skeptic. Although he believed that all of our knowledge was derived from sense impressions, he also believed that all knowledge is entirely reducible to the impressions themselves, which for Hume included not merely those alterations of the exterior sense powers but any emotion or psychological response which was not stimulated by the exercise of the human will, and not the sensed thing as such. Following in the footsteps of Berkeley, he asserted that all perception, that is all reception of impressions, is inescapably subjective. Consequently, anything which could not be reduced to the impressions of the senses was something which could not be said to be known, at least, not known with certainty (and thus, in the tradition of Descartes, not really known). The ideas produced by these impressions do not provide any knowledge of extramental things in themselves, i.e., of what Hume calls “matters of fact.”
Whereas previous philosophers had been concerned to some degree or another, consciously or not, with how it is that man acquires knowledge of things’ natures, that is, their intrinsic ordering principles, Hume disavowed the possibility of such a “secret power” ever being discovered. Rather, he asserted, our sense impressions are disparate and isolated incidents, each of which is responsible for bringing some idea into our minds; the association of these ideas came about not from anything gathered from the sense impressions themselves except the accidental juxtaposition of their occurrence. In other words, the realization that events A and B frequently, perhaps even always, occur in succession is itself a new impression, for Hume; but one where the object sensed is not the relation of A and B as such, but the incidental relating of them in the mind of the one sensing. In other words, Hume does not believe that the mind can perceive relations among things outside the mind, but only note that it relates them mentally by the power or faculty which he terms custom or habit.
Thus, we ascribe common names to things of certain appearances because it is convenient, and because they are consistent in the way in which they appear to us, but the names do not indicate any necessary aspects of those things. Consequently, because the appearances are determined extrinsically and the names which signify the ideas which we actually know are given only conventionally, Hume asserts, there is no real knowledge of the outside world, except that which is given in the most basic of sense impressions. Rather, the relation of ideas in the mind to things in the outside world—what Hume calls “matters of fact”—operates only by means of probability; that is, based upon prior experience that what is contained in sense impression A has been consistently followed in temporal sequence by what is contained in sense impression B, we may assert upon again seeing something similar to A, that B will likely follow. But because “causality” is not something which originates in the impressions of the exterior things, we cannot say “If A, then B”, or that A is the cause of B, only that we relate A to B as cause to effect based upon prior experiences—not based upon any essence or properties A or B themselves. Consequently, the causal relation is for Hume only a “mental” being, not a “real” one. The causal relation is a fiction of our intellect.
The denial of the knowledge of causes flies right in the face of the Aristotelian-Scholastic (and especially Aristotelian-Thomistic) tradition of philosophical science. As Aristotle asserts repeatedly, and Thomas after him (among many others), we truly know something—that is, we have episteme or scientia, science, certain knowledge, the kind of knowledge sought in theoretical inquiry—only when we know it through its causes. Although Hume indicates the innate desirability of possessing such knowledge, he rejects its pursuit. Instead, he advocates the subservience of such theoretical inquiries to the advancement of practical goals. Theoretical inquiry should be carried out only insofar as the ideas which it develops or discovers can be applied to the world outside.
Kant’s Theory of the Sciences
Hume’s ideas, though not ignored by any means, were not widely lauded in his lifetime. The most popular version of his short work, An Enquiry Concerning Human Understanding, was published posthumously. His work was often derided as being overly skeptical, heretical, and atheistic; adjectives not commonly found favorable in the 18th century United Kingdom. Nevertheless, he was profoundly influential on a number of philosophers who were in turn influential upon the whole world, including the economist Adam Smith, the famous utilitarian Jeremy Bentham, the evolutionists Charles Darwin and his follower Thomas Henry Huxley, and, most importantly when it comes to the study of metaphysics, Immanuel Kant, who wrote that reading Hume “interrupted [his] dogmatic slumber.”
This phrase, “dogmatic slumber,” should be parsed. Typically, “dogma” and “dogmatism” are associated with the teaching of a religion, and are often used pejoratively, connoting a slavish and unthinking obedience to a set of doctrinal points. In Kant’s usage it refers instead to the systematic idealist metaphysics which Kant was taught at the University of Königsberg. Where Christian Wolff, the man primarily responsible for the teaching of this idealist metaphysics at Königsberg, had been concerned with developing a system based upon idealist principles, Hume was concerned with continuing to question what it really means to say that we know, a question which Wolff and his disciplines had not definitively answered, a question which, given their principles, they could not actually hope to answer. Thus, in his early work, Kant faithfully reflected this idealism found in the writings of Wolff and in those of the more-widely known Gottfried Wilhelm Leibniz, who held similar notions about human cognition and idealist metaphysics. It would, however, be a mistake to interpret the interruption of his “dogmatic slumber” as meaning that he abandoned the idealism of the Wolffian school. Indeed, he clearly states that he did not adopt Hume’s conclusions, but rather that he took the English empiricist’s qualm about evidence for the connection of cause and effect as “a well-founded, but undeveloped thought,” upon which he hoped “by continued reflection to advance further than the acute man to whom [is owed] the first spark of light.” Where Wolff and his followers continued their attempts to advance idealism, providing definitions and descriptions of concepts such as essence, cause and effect, truth, goodness, and so on, Kant turned his attention to the “critique”—that is, to forming doctrine which establishes the fundamental structures of human knowledge which allow anything to be known whatsoever, and thus to establish the boundaries of human inquiry in accord with the limitations of the human mind. Such a critique would in theory synthesize idealism, the school of Wolff, Leibniz, and Descartes, with empiricism, the theory of Locke and Hume. Only after this primordial philosophical task, the foundation of a critical philosophy, Kant maintained, could anything meaningful be said or done in regard to scientific or philosophical inquiry of any kind.
The “first spark of light” which instigated Kant’s critical endeavor was Hume’s objection that the notions of cause and effect, and the innate relatedness that they have to one another, cannot be found in the content of experience. Kant tried to put this objection in a “general form, and soon found that the concept of the connection of cause and effect was by no means the only concept by which the understanding thinks the connection of things a priori, but rather that metaphysics consists altogether of such concepts.” In other words, that there are a number of concepts which are something which must be “thought” or somehow possessed a priori, i.e., such that they are necessary or cannot be otherwise, and which are entirely antecedent to or independent of any actual experience. Such concepts include, for instance, affirmative or negative qualities, hypothetical relations, contingency and necessity, cause and effect, and so on. What is common to all of these, in the Kantian epistemological theory, is that the notion expressed by each concept cannot be found in the content of things experienced; that is, the cognition of something as a cause or as an effect, for instance, cannot be reduced to sense impressions. But whereas Hume insists that the connection of cause and effect arises as a psychological impression formed by the constant juxtaposition of similar sense impressions, Kant claims that the connection of cause and effect is an innately possessed concept to which things’ appearances can be adequated.
The pursuit of this question led Kant to an inevitably unsuccessful but nevertheless profoundly influential recasting of the foundations of science, and especially with regard to the question, “is metaphysics at all possible?” While this question is more fully answered and expounded upon in Kant’s Critique of Pure Reason, it is considered more broadly, though more succinctly and even more fundamentally in the Prolegomena to Any Future Metaphysics, which intends “to point out what must be done in order to make a science actual if it is possible”. In other words, the Critique looks intensely at the question of the actuality of scientific knowledge, whereas the Prolegomena looks at the question of how a possible science can become actual; in both cases, Kant denies the possibility of metaphysics being a science of the supersensible real.
The Thomistic Revival
Seventy-five years after the death of Kant, Pope Leo XIII published an encyclical, Aeterni Patris, which resulted in a revitalization of the traditional scholastic metaphysical philosophy. Observing that “false conclusions concerning divine and human things, which originated in the schools of philosophy, have now crept into all the orders of the State, and have been accepted by the common consent of the masses”, Leo exhorted Catholics to return to a study of philosophy, and especially the philosophy of St. Thomas Aquinas. This call was taken up (though some through a roundabout way) by a number of men, the most influential of whom were Etienne Gilson, Reginald Garrigou-Lagrange, and Jacques Maritain. They, and many others, brought Thomistic thought back to life after a centuries-long diminution and especially emphasized the metaphysical aspects of the Common Doctor’s doctrine.
In particular, the question of being has been taken up with a renewed vigor: what is being? What can we know of being? Can we discern first and ultimate principles which give an explanation for the existence of things? Can we know eternal, immutable truths? Can we know Truth itself?
It is in this tradition that we will pursue the following questions: how do human beings know anything at all? Does human knowledge entail knowledge of the supersensible? Can human beings know God by reason alone? What can human beings know of God—that is, to what extent, in what manner, can we say we know what God is? But before we can pursue these questions, we must: first, examine how modernity came to reject metaphysics as irrational; and second, provide an Aristotelian-Thomistic preface to the metaphysical question, wherein we clarify the concept of nature, ignorance of which makes an approach to metaphysics very difficult, if not entirely impossible.
 We are using this term as it is employed by Jacques Maritain in The Degrees of Knowledge, and by which he means the application of quantitative measures (metrics) to sensibly observable phenomena (empirio-). More broadly, we could speak of the methodology of idioscopic (or ideoscopic) science, the study of things according to a determinate instrumentation or experimentation within a particular field of inquiry, as initially distinguished from cenoscopic science, the pursuit of understanding by natural reasoning alone, a distinction initially made by Jeremy Bentham and elaborated upon by C.S. Peirce.
 Do not mistake our intention: we are writing specifically for our audience, i.e., the college student. Many people can live their lives well, happily, and virtuously, without pursuing knowledge of the metaphysical. But for those called to a higher education, to be leaders in the world in business, medicine, law, academics, and every walk of life, the metaphysical question and the search for wisdom are pursuits the avoidance of which imperils the well-being of not only themselves, but also all who might end up following or admiring them.
 To place a specific date on the beginning of modern philosophy—or any period of philosophy, for that matter—is always suspect. Descartes was influenced by many previous thinkers who are not typically considered modern, but without whose influences modernity would never have arisen; likewise, although modern philosophy, as a period, is most certainly over, its influences are still felt in many ways, and the systems of many philosophers are largely determined by accepting some of the very same presuppositions of modernity which are at the root of its flaws.
 To be precise, “cogito ergo sum” is never said in the Meditations—but rather, in §7 of The Principles of Philosophy, as well as (in French) in the Discourse on Method, “Je pense, donc je suis.” Nevertheless, the same sentiment can be found in Meditation II: “hoc pronuntiatum: ego sum, ego existo, quoties a me profertur, vel mente concipitur, necessario esse verum.” “This statement: I am, I exist, as often as it is advanced by me, or conceived by the mind, is necessarily true.” It should also be noted that the assertion of the cogito, as something necessarily true, does not originate with Descartes, and can be found in both Thomas Aquinas (De veritate, q.10, a.12, ad.7) and St. Augustine (De civitate Dei, XI.26; Enchiridion, c.7, n.20); rather, Descartes is the first to make it the methodological starting point of his philosophical system.
 Characterized by the philosophers Gottlob Frege, Bertrand Russell, Ludwig Wittgenstein, Saul Kripke, and others.
 Including thinkers such as Edmund Husserl, Martin Heidegger, Edith Stein, Jean-Paul Sartre, Maurice Merleau-Ponty, Hans Georg Gadamer, Paul Ricoeur, Eric Voegelin, and many others.
 I am using this term to designate broad group of thinkers among whom the most well-known are the Thomists, such as Reginald Garrigou-Lagrange, Etienne Gilson, Jacques Maritain, Charles De Koninck, Joseph Marechal, Bernard Lonergan, Karol Wojtyla, and many others.
 It is an unfortunate reality that Thomism, despite having a broad common appeal and a growing number of adherents, does not represent a truly unified movement in the 21st century. It is sometimes said that there are as many forms of Thomism as there are Thomists. This difficulty stems from the ambiguity of certain texts of St. Thomas, which lend themselves to a multitude of interpretations; oftentimes, the brevity with which he explains his position leads to seemingly contradictory or at least difficult-to-reconcile statements. It is my belief that there is a consistent hermeneutic through which to interpret these texts, and a mode of Thomism which is both true to St. Thomas himself while remaining open to developments and further elucidations. But this is another matter, outside the scope of what I am attempting to explain in this work; as such, I am adopting the term “moderate Thomistic realism”, though I might as well take up “critical Thomistic realism”, “critical Thomistic existentialism”, or “existential Thomistic realism”. No one term captures the position fully; it remains a work in progress.
 Locke, An Essay Concerning Human Understanding, 82.
 Ibid., 84.
 For more, see below:
 To establish that the extramental reality of things—that is, of ideas, spiritual beings (including man) being realities of an entirely different sort (active, as opposed to the passivity proper to the ideas)—is not contingent upon man, Berkeley proposed that the ideas or perceptions of all things are determined by God, and man knows “objective” reality when his understanding of the ideas is commensurate with the ideas of God.
 Kant, Prolegomena, 5.
 Ibid., 6.
 We will look at the various “categories” of the understanding which are thought a priori in a later section.
 Kant, Prolegomena, 19.
 At the same time, and largely independently, the phenomenological school of thought began to develop, influenced by the work of Franz Brentano and particularly his (diluted) notion of intentionality,
 Aeterni Patris, §2.