Most people have a certain set of standards about what they believe and how to live their lives. But most people don’t bother to write out each one—with citations—on the internet.
isn’t most people.
On his , the University of Notre Dame professor of philosophy details 100-plus philosophical views that he has published in books or journal articles, covering topics from deontology (No. 17) to supererogation noninheritance (No. 72).
“In philosophy, you take your views—about how you ought to live, what to believe, what does and doesn’t exist, whether you have free will, the place of science—and try to make that all coherent,” Portmore said.
Now, he’s compiled many of his views into a book, , forthcoming with Oxford University Press. In it, he shares his personal worldview, which combines the principles of utilitarianism and consequentialism with the ideas of 18th-century German philosopher Immanuel Kant.
Consequentialism defines the moral value of an action by its consequences, and utilitarianism applies consequentialism by assigning value to actions that maximize happiness. Based on utilitarianism, the ends always justify the means, and a person is only as valuable as they are happy.
“It’s very important for all of us to be critical thinkers.”
Conversely, Kantianism asserts that people are inherently valuable, regardless of the happiness they bring, and therefore should always be respected.
In Kantsequentialism, Portmore seeks to combine the best parts of those often-at-odds philosophies.
“In my view, one thing that matters is respecting people’s decisions,” said Portmore, who came to Notre Dame in 2025 after spending 20 years at Arizona State University and five at California State University, Northridge. “But another thing that matters is how much good there is in the world.”
Looking at the world through Portmore’s view involves more nuance than one sentence can contain—hence the 106-item list and 500-page book. But what he wants from the study of moral philosophy can be put simply: “Tell me how I want the world to go, and then tell me which of my options will make the world go that way.”
Unlike other academic fields, philosophy can’t give Portmore answers through observation or experimentation. Therefore, his research goal is to compile a worldview, and as a professor, to help students find their own worldviews, too.
In addition to the individual research and teaching, Portmore is developing a research program in ethics as a program chair for the . His work aligns with and enhances the , which supported his recruitment and appointment last year.
As part of the initiative, Portmore recently convened a two-day workshop that brought together ethical philosophers, including faculty and graduate students, from the University of Michigan and Notre Dame for a weekend of intellectual exchange in Saint Joseph, Michigan. All attendees presented work in progress across a broad range of topics and received feedback from peers.
“Michigan is not only geographically convenient, but both of our schools have an incredible department of ethicists and philosophers,” said , associate professor of philosophy at Notre Dame and one of the workshop co-planners. “People put a lot of effort into their feedback, making it sharp, but constructive in spirit—and multiple attendees said it was the best feedback they’ve received on their work.”
Portmore is also shaping philosophical conversation globally as editor-in-chief of Ethics: An International Journal of Social, Political, and Legal Philosophy, which has published scholarly work for over a century. He reviews more than 700 papers submitted each year, helping both rising and established philosophers make their mark in the field.
“It’s a way to pay back the community that gave me this wonderful profession,” Portmore said. “My life as a philosopher changed when I got my first publication in the journal that I now edit.”
Complete understanding
At the beginning of his scholarly career, Portmore traveled to Australia to study under the famous utilitarian Peter Singer at Monash University’s Centre for Human Bioethics.
Singer is known for his belief that an individual’s value is solely dependent on how happy they are—going so far as to claim a happy rabbit’s life is considered more valuable than an unhappy human.
Portmore initially agreed with him, because he was fully aligned with utilitarianism at that time and was determined to bring all other philosophers into the fold. He wanted all to agree that actions and their consequences—and the worlds they create — should be ranked according to the point of view of the universe.
But as Portmore learned from and debated other Monash faculty, it became difficult to convince himself of utilitarianism, let alone other scholars.
“The more I thought about it, I thought, ‘Why should I do that?’” he said. “I have reasons to want some worlds more than others that have nothing to do with the point of view of the universe.”
That realization put Portmore on the path towards developing Kantsequentialism. It wasn’t his first turning point; in fact, when he started his undergraduate studies at the University of California, San Diego, he thought understanding the world would be fulfilled by studying science, not philosophy.
But Portmore realized the field wasn’t for him when he saw how many assumptions scientists take for granted. For example, one philosophical theory called idealism suggests that reality is entirely made up of ideas and thoughts, not anything physical. While Portmore admits he personally thinks idealism is patently false, he argues it’s still a perspective that needs to be considered.
“Some people think philosophy doesn’t make any progress because we’re still talking about the same things that Plato and Aristotle talked about thousands of years ago. I make progress when I see students open their eyes and start questioning the assumptions of the previous generation.”
“Scientists don’t argue that their view is better than idealism; they just assume that idealism is false and move on,” he said. “So if I want to understand the world completely, science is not where it’s at.”
That’s an easier process with support from one of the world's largest philosophy departments. Notre Dame’s continued investment in the humanities, Portmore said, has attracted and developed a strong cohort of other ethical philosophers with whom he can discuss ideas. It’s a place where he has found others like him who seek understanding.
Understanding the world is more than a matter of intellectual curiosity, Portmore said, because society can make grave errors when things go unquestioned. Ideas ranging from geocentrism to enslavement were once widely accepted norms, he said, and philosophy seeks to root out other harmful ideas from modern society.
And that’s why Portmore believes philosophy isn’t just for philosophers.
“It’s very important for all of us to be critical thinkers—ones who don’t just accept something because your parents accepted it or the generation before you accepted it or your culture or your nation accepts it,” he said. “It’s important to learn to question those things.”
Teaching disagreement
A large part of Portmore’s role as a philosopher is teaching his students how to question everything, whether they’re first-years completing the or accomplished Ph.D. candidates.
He gets particularly energized when students begin examining all areas of their own lives: Should we be eating meat? Does God exist? Should we be giving to charity? Is science infallible? How do we know we’re not dreaming?
“I’m not there to teach them certain facts,” Portmore said. “I’m teaching them a set of skills and trying to elicit some intellectual curiosity in them, a willingness to be open-minded and to critically reflect on what they were brought up to believe.”
That can be difficult in introductory courses full of students with no particular interest in philosophy, and especially with those hesitant to openly disagree with their professors. When Portmore brings up something like idealism, he doesn’t want his students taking notes—he wants them to say, “That’s insane!”
Once students learn that it’s OK to disagree, Portmore said, he can teach them how to disagree properly and express themselves effectively. Those are key skills for every student, no matter their major.
Everyone should spend time thinking about how they should live their life, Portmore said. and that process moves forward every time someone asks a question.
“Some people think philosophy doesn’t make any progress because we’re still talking about the same things that Plato and Aristotle talked about thousands of years ago,” he said. “I make progress when I see students open their eyes and start questioning the assumptions of the previous generation.”
Originally published by at on September 29, 2026.