The philosopher Joseph Boyle passed away on the morning of September 24, 2016. He had been diagnosed with an aggressive and inoperable brain tumor less than two months earlier.

The loss falls particularly hard on those of us who knew Boyle personally. But Boyle’s intellectual influence spread far beyond his immediate circle of acquaintance and those who read his scholarship directly. His founding work in the New Natural Law Theory has had a pervasive influence on a generation of philosophers (as well as philosophically trained lawyers, physicians, and scientists), and has been a continual on- and off-stage presence on the pages of Public Discourse.

While the earliest exponent of this theory was Boyle’s doctoral supervisor, Germain Grisez, Boyle and Oxford law professor John Finnis became so closely associated with Grisez and his approach to natural law theory that the view is still referred to as the “Grisez-Finnis-Boyle” theory, or “GFB” for short. That theory—and the work of Boyle in particular—has had a deep and lasting impact on the content of Public Discourse.

Boyle was born in 1942 in Philadelphia and did his graduate work at Georgetown University, where he studied with Grisez. His dissertation, which he defended in 1969, was about philosophical positions that are self-refuting, that contain, as it were, the seeds of their own destruction. Boyle argued that some statements could be performatively self-refuting. That is, their performance, such as their utterance, or assertion, could be such as to refute the claims made in the performance—as when someone claims that it is impossible to make a claim.

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This recognition opened up various argumentative possibilities in dealing with foundational claims in philosophy. Boyle, Grisez, and my father, Olaf Tollefsen, collaborated in the early 1970s on a book, Free Choice: A Self-Referential Argument. There they showed that the denier of free choice must be appealing to what they called a “rationality norm” in asserting that there is no free choice. Essentially, such people are asserting that “no free choice” is the reasonable and responsible intellectual option that reasonable and responsible believers would accept if they were appropriately guided by the evidence: it is what they ought to believe.

But appeal to a rationality norm—and to the “ought” that calls for responsible belief—is pointless unless those being addressed are free to believe (assent) responsibly. The performance of making the assertion that there is “no free choice” and appealing to how one ought reasonably to believe is thus performatively self-defeating. The assertion that there is “no free choice” can have a point only if that proposition (“no free choice”) is false. So it is reasonable to judge that the “no free choice” claim is itself false, and free choice is vindicated.

Both the vindication of free choice and the argumentative methodology that recognizes the self-defeating quality of certain claims is essential to the work of thinkers with whom all PD readers are familiar, such as John Finnis, Robert P. George, Patrick Lee, and others. The methodology is used to good effect in a 2010 Public Discourse article by Mark Latkovic titled “Are You Out of Your Brain? Reflections on Free Will and Neuroscience,” as part of an argument against materialistic accounts of the nature of the human mind.

Boyle’s influence is seen elsewhere in the PD archives. For example, the New Natural Law theory is known for its controversial view that intentional taking of human life is always wrong. Why is this controversial? Because it seems to rule out traditionally accepted practices such as capital punishment and intentional killing by state actors in warfare. I have argued for this view in a number of essays for Public Discourse, essays to which other thinkers such as Edward Feser, Fr. Wilson Miscamble, and Nigel Biggar have responded. My work on this topic, on which I hope to write a book in due time, is deeply indebted to a series of essays of Boyle’s on the sanctity of human life.

Indeed, were it possible to trace the strands of Boyle’s influence through the range of topics covered at PD by various authors, the endeavor would need to include the following topics and more: the first-person nature of intention, the right to private property, the right to life, the right to healthcare, the first principle of morality, justice in warfare, the incommensurability of goods, religious freedom, the ethics of lying, and end-of-life ethics. In all of these areas, thinkers such as I, Ryan Anderson, Sherif Girgis, Samuel Gregg, Adam MacLeod, Bradley Miller, Patrick Lee, Gerard Bradley, Melissa Moschella, Christian Brugger, and others have articulated and defended a consistent natural law approach deeply shaped by Boyle’s work.

PD readers interested in that impressive body of work can go to the “About Joseph Boyle” page on Germain Grisez’s website for an expanded personal biography and links to Boyle’s most important work. There they will learn much and get a glimpse of the deep rigor and insight that characterized Boyle’s thinking. But they will only have scratched the surface of a remarkable personality.

To discuss that, I must now speak only of “Joe,” as he was known to his friends. Joe was a large, intimidating, and growly Irishman. Sterling Hayden with a big beard reminded me of Joe—not the other way round. His enthusiasm was infectious: to hear him speak of a trip to the Bushmills distillery in Ireland or of stomping grapes in his basement to make red wine was to hear the words of a man inspired. People speak of a “glint” in someone’s eye, usually metaphorically, but I suspect many would attest to the presence of a real glint in Joe’s.

To watch him in an argument was an experience. If he did not think an argument was living up to the canons of reason and responsibility, then one would hear about it: “Oh, come on!” he would exclaim, a phrase that drew a smile to those near him even at the end when he was ill. But while one might be abashed, his exasperation was also a delight to his friends.

This was in large part because behind the exasperation lay a recognized generosity of spirit and willingness to engage with any interlocutor of good will. Joe could be fierce in argument, but it was a joy to argue with him; one’s own arguments always emerged stronger. This was, in part, a natural gift, but I think it was also shaped by his experiences arguing at length with Elizabeth Anscombe when, late in her life, she would visit Joe and his wife Barbara at their home in Toronto. In his introduction to a talk he gave in the last year of his life at the Anscombe Centre for Bioethics, at Oxford, Joe noted the length and intensity of their discussions. “Not every moment of every conversation was necessarily . . . pleasant,” he said with a smile. “But the overall experience instructed me, I hope.”

I, and many others, would say the same of our experience with him. Joe’s conversation instructed me, and I would be a far worse thinker, writer, and philosopher were it not for Joe’s presence in my life.

I have a colleague, George Khushf, who knew Joe for perhaps twenty years, dating back to when he was a graduate student. He and Joe had great mutual admiration for each other, but over the past year and a half, in producing an article for something I was editing, George had the opportunity to really go through a lot of Joe’s work. Months before any of us knew Joe was ill, George would approach me and tell me how much he was enjoying Joe’s writings, and how much he was learning from it.

But when he heard that Joe was terminally ill, he said “I had hoped, after all this reading, that I would be able to talk to Joe again about his work, which I understand now better than I ever did before. And what I really wanted to talk to him about was the Kingdom of Heaven.”

That topic was close to Joe’s heart. In part this was, I believe, because Joe recognized in a profound and personal way that the Kingdom was God’s answer to the blights, miseries, and sufferings that afflict even the best human lives. Joe and my father, also a philosopher, were extremely close friends. Joe took my father’s early death, at age forty-five, leaving behind seven children and my mother, to be a kind of paradigm of the occasional (and sometimes more than occasional) “terrible shittiness of human life.”

But, Joe told me shortly after my father’s death, in the Kingdom my father would have all of eternity to work out the fulfillments of his special talents and gifts, in communion with the saints and Our Lord. That image has stayed with me for almost thirty years now, and is with me still as I think of Joe and mourn his loss, while also looking forward to the restored communion with him and other loved ones in the Kingdom of the Blessed.

It is, of course, impossible to do justice to anyone, and certainly to a larger-than-life personality like Joe, in a brief remembrance such as this. Joe has been a colleague, mentor, and friend to many of us associated with Public Discourse and in the broader academic community. We’ll cherish our memories of him as we continue to learn from his work, and we will miss him sorely.

Rest in peace, old friend.