The 2016 data breach of the personal Gmail account of John Podesta, chairman of Hillary Clinton’s 2016 presidential campaign, garnered much attention from Catholics. They took umbrage at an email exchange discussing the possibility of a “Catholic Spring” aimed at fundamentally changing their identity and beliefs. In that conversation, John Halpin, a Catholic and fellow at the Center for American Progress, noted that many “powerful elements” in conservatism are Catholic. He speculated that “they must be attracted to the systematic thought,” and added, “they can throw around ‘Thomistic’ thought and ‘subsidiarity’ and sound sophisticated because no one knows what the hell they’re talking about.”

I’m not sure Halpin knows “what the hell” Thomistic thought is, but I certainly wish he—and all Americans—did. Thomism, 745 years since the great theologian’s death, remains perhaps the best philosophical system available to the West.

As I’ve argued elsewhere at TAC, we are all philosophers in the sense that we all develop, either consciously or subconsciously, a system of thought for evaluating ourselves, the world around us, and what counts as truth. We make choices, form opinions, and offer arguments, all based on philosophical presuppositions. When we go with “what works,” we channel the pragmatism of William James and John Dewey. When we seek to maximize sensual pleasure and minimize pain, we are drinking from the well of John Stuart Mill’s utilitarianism. When we act off of scientifically verifiable data, we are the intellectual heirs of empiricist David Hume. Those who believe morality can be changed by will honor the memory of Friedrich Nietzsche. And those who reduce human persons to their economic output have embraced the thinking of Karl Marx.

There are fundamental problems with all of these philosophies. One error that unites them is a belief, either explicit or implicit, in materialism, or the idea that man (and reality) is reducible solely to what is material, what can be sensed, and what can be empirically studied. Even that which separates man from all other animals—his intellect and will—are explained away as physical properties. Yet without an intellect and will, appeals to an essential human dignity quickly collapse. We are all just a bunch of colliding atoms in a universe of colliding atoms. It’s just that our atoms are a bit more evolved and sophisticated than everything else.

Thus do all these philosophical systems tend to dehumanize man and overemphasize certain goods at the expense of others. For example, pace the pragmatists and utilitarians, of course we should prefer things that work over things that don’t work and pleasure over pain. But sometimes what “works” isn’t immediately perceptible to our senses. Additionally, the greatest pleasures in life sometimes require great sacrifice and suffering. Making decisions based on empirical data is a good, but not all things worthy of our attention can be empirically derived (e.g. the arts, human love, knowledge of eternal truth). There is something to Nietzsche’s argument that knowledge can be an instrument of power, but his claim that reality as we know it is simply an artificial creation of our minds unravels when one asks whether his own presuppositions are really real or just perspectives he has created and thus just as ephemeral as everything he attacks. Marx was right to recognize that man’s economic output contributes to his dignity and value—but it certainly isn’t the sum of his worth.

Who can save us amid this messiness? I would offer Aquinas. His philosophy doesn’t get as much attention as other philosophers, and certainly not as much as those of the Enlightenment and post-Enlightenment. When Americans think of Aquinas, if they ever do, they’re more inclined to think of his role in Christian theology, especially his contribution to the Catholic doctrine of transubstantiation. Perhaps if they’ve taken introductory theology or philosophy courses, they’re aware of his famous “Five Ways,” or proofs of the existence of God, which prominent New Atheist Richard Dawkins sought to take to task (and failed) in his bestselling book The God Delusion.

Yet Aquinas is a philosopher par excellence who is worthy of our attention. He stands tall on his own merits as the one who “was able to provide the principles,” to quote French philosopher Pierre Manent, for political communities governed by reason and grace. Yet his value also lies in the larger intellectual project of which he is a part. By this I mean that Aquinas, in a way that was perhaps unprecedented in the 12th and 13th centuries, consolidates the wisdom of the Western tradition into a coherent whole. He draws upon an impressive variety of sources. Certainly Holy Scripture and earlier theologians like Augustine, John of Damascus, Dionysius the Areopagite, and Anselm loom large in his work, though he is also incredibly well-versed in the history of philosophy.

It was Thomas who “baptized” Aristotle by appropriating significant chunks of his philosophy, including such concepts as act and potency, hylemorphism, the four causes, essence and existence, transcendentals, and being. Even Aquinas’s proofs for God’s existence, as many Thomists have noted, are drawing upon Aristotelian premises. He also builds his philosophical system upon the shoulders of Plato, Cicero, Boethius, Avicenna, Averroes, Al-Ghazali, Maimonides, and John Scotus Eriugena. This enterprise reflects conservatism at its best: studying, honoring, and incorporating the very best of our intellectual forebears, while carefully and humbly critiquing where they went astray.

Aquinas defends the immateriality of the intellect and will, essential to any political or social framework that posits that man has inherent dignity. He does this by arguing that the objects of the intellect and will are immaterial. In other words, one is able to think (via the intellect) and act (via the will) towards certain goods that are not physical. When a person considers the idea of happiness, fame, or beauty, he is thinking of an essentially immaterial thing, something universal and incorporeal. When he takes actions to achieve those things, his will moves towards something that is essentially immaterial. If man possesses incorporeal qualities, that means there is a part of him that is incorruptible and thus transcends his bodily existence. It is from this recognition of man’s spiritual nature found in his intellect and will that society can form a coherent conception of human dignity and rights.

This connects to other elements of Thomistic thought worthy of consideration—his contributions to human psychology and ethics, topics philosophy professor Edward Feser addresses in his excellent treatment of Aquinas. In reference to psychology, Aquinas’s hylemorphic dualism, or the premise that things are composed of both matter and form, well accords with modern neuroscientists’ observations regarding the intimate relationship between our brain processes and our mental lives. Another psychological example draws upon the aforementioned four causes: material, efficient, formal, and final. If neurological processes are the material- and efficient-causal side of a given set of events, of which the mental aspects are the formal- and final-causal side, then we have a coherent explanation for how the mind has causal influence on the body.

In reference to ethics, Aquinas offers us a more robust and objective understanding of the nature of the good than Hume, viewing goodness as what best conforms to truth and a thing’s proper end. Hence a triangle is “good” inasmuch as it approaches a perfect, three-sided object whose angles add up to 180 degrees. A good person would be one that best exemplifies the qualities that define human excellence (e.g. strength, wisdom, virtue). Moreover, “goods” are those things that best accord with our nature—some activities help us grow, while others weaken and infantilize us. This then leads into natural law theory, or the ideas that help man compose an understanding of society without necessarily falling on divine revelation, and thus is accessible even to non-Christians. It can be summed up by Aquinas’s famous assertion: “Good is to be done and pursued, and evil is to be avoided.”

In a recent op-ed for The Washington Post, Michael Gerson critiques those who prize “authenticity” and uncensored “passion” over self-control and contemplative restraint. He contrasts two philosophical systems, one reliant on Aristotelianism, the other derived from Jean-Jacques Rousseau. In the former, “human beings fulfill their nature by exercising their reason and habituating certain virtues, such as courage, temperance, honor, equanimity, truthfulness, justice and friendship.” In the latter, “authenticity is at the apex of the virtues,” where “man is born free but is everywhere in social chains.” For Rousseau, man must thus seek to be true to himself because self-expression is the means to a “meaningful and happy life.”

This is a valuable distinction, and in Rousseau we can perceive the intellectual ancestor of utilitarianism and nihilism. Alternatively, Aristotle offers us a template for human behavior that endures. But he is not the only one to thank. It was Thomas Aquinas who synthesized the ancient Greek into a unified Western philosophical system that will stand the test of time.

Casey Chalk is a student at the Notre Dame Graduate School of Theology at Christendom College. He covers religion and other issues for TAC.