Atheists—and that’s nearly everyone in my neck of the woods—might see the title of Quintus Curtius’s latest triumph and be tempted to shuffle along. The gods? Their “nature”? Isn’t that something for the faithheads?

How wrong they would be, for Cicero’s often forgotten treatise is the foundational work of free thought in the Western tradition. Written less than two years before he was assassinated, On the Nature of the Gods is the funnel point of all prior Greek theorizing on who or what is responsible for everything in existence—if anyone or anything is responsible, that is. (Remember that ancient Greek texts did not circulate in the West until the end of the Middle Ages or later; even today, much of the Greek philosophy referenced by Cicero is lost to us.) For, as Cicero himself asks in it,

What about those who have said that the whole idea of the immortal gods was invented by wise men for the sake of political and social order, so that religion might guide to their responsibilities those who could not be led there by rational argument?

Eighteen centuries later, the French philosophe Voltaire looked back and pronounced On the Nature of the Gods “one of the two finest books human wisdom has ever written.” It’s not hard to see why: all the ancient origins of the Enlightenment are to be found right here in it. And in Quintus Curtius’s outstanding new translation, it is now easier than ever for the non-Latinist to see what Voltaire was so excited about.

Quintus Curtius is the pen name of the trial attorney and former U.S. Marine Corps officer George J. Thomas. Since first encountering his work eight years ago, I have become a committed apostle. Quintus is the finest translator of Cicero we have seen in many years, and he deserves credit for helping to launch the resurgence of interest in Cicero’s philosophical works that is now thriving outside the ivory tower.

On the Nature of the Gods is a philosophical dialogue, to be sure, but it’s set up like a joke. Just as the proverbial priest, rabbi, and minister walk into a bar, so here an Epicurean, a Stoic, and an Academic skeptic walk into a villa. And instead of wrangling back and forth and blow for blow, as they might in one of Plato’s dialogues, the three worthies here make long speeches akin to a lawyer’s brief, a sermon, or a best-case scenario for the gods. When one finishes, the next speaker immediately steps forward to skewer that speech. The starting point of the first speech, the Epicurean’s, is the obvious proposition that the gods don’t exist at all.

Again, anyone who assumes that such a debate among philosophers is ancient history or settled science would be grossly mistaken. All three worldviews flourish all around us and shape lives presently; they have merely donned new robes and new identities. First, the Epicurean of antiquity is the secular humanist of today. He is your garden-variety atheist, albeit one canny enough to dissemble his disbelief in public. Next, with an ardent commitment to divine providence and intelligent design—more on that in a moment—yesterday’s Stoic is today’s Christian. And finally, the Academic skeptic of ancient times is the agnostic of today: the man or woman who deems the evidence too inconclusive to decide either way.

The biggest surprise is that in these pages, this last figure—the skeptic—settles on a worldview very close to deism, the philosophy which says yes to a creator god but no to miracles, divine revelations, prophecies, human stand-ins, and the like. Hardly anyone is a self-affirming deist today, but the philosophy flourished in colonial America and can be detected in the founding political documents of the United States.

Far and away the most compelling feature of the book is that once each speaker has had his say, his perspective is subjected to sustained—indeed, withering—cross-examination. As Cicero must have realized from his legal work, no finer instrument for exposing hooey has ever been devised. As he has a character say here,

It doesn’t as easily come to my mind why something might be true, as why it might be false. . . . If you ask me what I think the nature of the gods might be, I probably wouldn’t have an answer.

Thus in Book I, the Epicurean/secular humanist goes on at length about how the universe simply . . . is: how random atoms falling through space and evolution explain everything, and that, yes, the gods do exist, but they dwell far away and have nothing to do with us at all.

That stance on the gods will remind readers of Stephen Jay Gould, the Harvard paleontologist who used to maintain, with a straight face, that science and religion are “non-overlapping magisteria.” The Stoic/Christian, who speaks up in Book II, immediately singles out the argument as the artful dodge it is, and he subjects it to a blistering rebuttal. The Stoic regards the gods’ benevolence as self-evident. Signs of their beneficent design, plan, and affection are all around us.

Just as some readers will be surprised that the Epicurean theory of evolution long precedes Darwin, so will legions of internet Stoics and cultural warriors be surprised to discover that the argument for intelligent design is not Christian in origin. For example, the Stoic says things such as this:

If a man were to come to a house, gymnasium, or forum, and were to see the underlying rule, plan, and method of everything happening there, he could not conclude that these things came about without an originating agent. He would understand that there is someone who oversees it all, and whose directions are followed.

And this:

The hand is adapted, through the motion of the fingers, for painting, shaping, carving, and eliciting sound from string and wind instruments. . . . Neither the human form and the design of our limbs, nor the power of the human mind and character, could have been made as they are by accident.

Just so, the Stoic is certain that the gods have a plan for us. That plan is what he calls providentia, “divine providence,” and he explains it at great length. Yet he warns us not to mistake the meaning of that word:

You said this in error, because you thought [the Stoics] created providence as a sort of unique goddess that manages and rules the whole world. But we are dealing here with a truncated term. For example, if one were to say that the Athenian republic is ruled by a “council,” the phrase “of the Areopagus” would be missing. So when we say “the world is controlled by providence,” we leave out the phrase “of the gods.”

Axiomatically, therefore, the Stoic is a firm believer in prophecy and divine intervention. He is sure that we humans are the gods’ favorite because unlike all the other animals, we have reason.

Readers today will easily spot problems with these arguments, and not merely because microscopes and telescopes have infinitely improved our understanding of the material universe. Voltaire himself demolished them long ago. The surprising thing—to me, at any rate—is that the speaker of Book III raises the same objections Voltaire did. He lacks the glee and fun of Candide, but the criticisms are all there. For example, is reason such a good thing? Not so fast, he says:

so too may a grievous moral offense be committed with the aid of reason. The former path is followed by few, and infrequently, while the latter route is chosen by many, and often. This being the case, it would have been better that no reason at all had been given to us by the immortal gods, than that it had been given with such pernicious consequences.

And as for “providence,” well, what good is it if it can’t prevent evil?

Your “providence” must be condemned, for it gave reason to those whom it knew would employ it for perverse and morally unsound ends. Unless, perhaps, you say that your providence was unaware of this outcome.

That gotcha! at the end is but one of many hilarious moments in the book. One of the interlocutors tells a story, for example, about a tyrant who plunders a temple and, sailing safely home, says with a laugh: “Do you see, my friends, how pleasant a voyage is given by the immortal gods to men who have committed sacrilege?”

Would you crack a joke like that as you’re robbing a church?

Why should we read Cicero’s book today? For its own merits, of course. But perhaps we have use for the book beyond the realm of the purely theological, because On the Nature of the Gods is anything but a Twitter fight or an HR lecture. As one speaker says,

But I don’t want you to think I’ve come as [the agnostic’s] supporter—I’m here to listen. My intention is to be a fair and unbiased listener. I’m not at all constrained by some knee-jerk, reflexive duty to endorse a predetermined view.

One can apply Cicero’s thinking and questioning strategies to some of the many numinous dogmas—social, political, medical, economic, and professional—that regulate our lives in liberal institutions and free societies today.

In any case, as the samples above show, this new translation strikes an ideal balance between readable modern English and scrupulous fidelity to the tone of the Latin. The outstanding introduction and the many succinct notes that round it out make it a complete book in itself. I recommend it highly.