Never one to shy away from tough questions, philosopher Amie Thomasson has tackled perhaps the most challenging of all in her latest book, Rethinking Metaphysics, published by Oxford University Press in April.
Rethinking Metaphysics completes Thomasson's ambitious trilogy examining metaphysics—the philosophical discipline that investigates reality's fundamental structure. Her previous volumes—Ontology Made Easy, which won the American Philosophical Association's Sanders Book Prize, and Norms and Necessity—systematically address metaphysics' two core questions: what exists, and what determines the nature of things.
Having clarified and demystified these foundational inquiries, Thomasson faced a compelling question: If these traditional problems can be resolved more straightforwardly than previously thought, what meaningful work remains for metaphysics? Rethinking Metaphysics offers her provocative answer—a fundamental reimagining of the discipline itself.
"We should figure out how we have used, and should use, terms that are really central to human life," says Thomasson, who was named one of the 50 most influential living philosophers in 2016. "It's not just playing with words. It makes an enormous difference to how we live, who has rights, how we formulate our laws, and how we undertake scientific investigations."
In a Q&A, Thomasson discusses her bold take on metaphysics and its far-reaching implications.
What do you think the purpose of metaphysics should be?
I envision the work we can do in metaphysics and other areas of philosophy as engaged in, roughly, figuring out how we should think and talk.
For example, think about hard questions, like: What is a person? This isn't a question for discovery. We have to decide how to apply the boundaries: At what age, from conception through maturity, will we say we have a full-blown person? Could chimpanzees or elephants be considered persons? If we understand that they also have social lives and intelligence, maybe even a moral sense, should they count as persons? What about AI systems? Can we develop a good enough AI robot that we should count as a person?
I think you can give good reasons for various views on this and the ways you ask the questions are going to change as time goes on. We have to try to figure out how the term has worked, and how it should work, and what we should do with it going forward. For example, what kind of legal recognition do these entities get, and how do we think about them? How do we protect the elephants or, eventually, the AI systems?
Can you offer examples of terms that are central to human life?
Freedom. Do we have free will? What do we mean by free will? What do we mean by freedom? Privacy, and notice how's that changing now as we get all sorts of data surveillance. The concept of knowledge—when we say that somebody knows or doesn't know. The concept of truth. Art.
All these concepts are very tricky to understand and are central to human life. I think philosophy has always been implicitly engaged in a lot of this work, and it's clearly something that's not made redundant by the advance of the sciences—in some ways it is made even more urgent by the advance of technology.
Did anything surprise you as you were researching this book?
For a long time, I'd been appealing to the functions of our language, when we talk about numbers or morality or possibility. People understandably challenged me on that and said, "How can you discover what the function is of a part of language, or resolve that question, when there are competing views about it?" I thought to myself, I really need a good notion of linguistic function—surely the linguists have made some progress on this.
Eventually I did find a stack in Baker-Berry Library about systemic functional linguistics, which is heavily influenced by anthropology as well as by some much older work in philosophy that asks questions about the functions of language in human life and the ways in which the grammatical structure of language helps serve the various functions in human life. It's not just about communicating with each other; it's also about interpersonal functions of taking up a social position, like being superior or inferior, or questioning and answering. And it's about textual functions and making a text flow together.
I started reading this stuff and realized that nobody in philosophy knows about this. I've been presenting this work now for about five years, and I've met only one other philosopher who happened to have a master's in linguistics and knew it. But this work on the different functions of different parts of language is super relevant to so many philosophical questions about properties, numbers, morality, the mind. I had to try to see what the implications would be. So being able to use that bit of empirical linguistics to help understand and justify claims about how (for example) our talk of objects functions, and how that compares to talk of morality, was the key breakthrough for me. I was super excited to find this work and then it had all sorts of cascading effects.
What do you hope readers take away from this book?
Philosophy is still relevant and important and worthwhile, because it's key to how we think, how we live, how we set up our society and legal institutions, how we conduct our scientific research, and so on. Its importance isn't because it's discovering deep facts about reality. Its importance is because it helps us make better, thought-through decisions about how we should think and talk.
The usual criticisms from philosophers are that if you think that metaphysics isn't about the world, then you make it trivial and uninteresting and only about language. But I think this approach shows a way in which we can see that philosophy is not a rival to the natural sciences. Yet it's doing something different that's both reasoned and important—not shallow and not just about words.
What's next for you?
The book has inspired me to do a more in-depth analysis of some particular concepts that have been central to philosophy. At the moment, I'm writing long papers on truth, morality or moral concepts, and law. I've got one paper already out on necessity and possibility. I want to do one on the mind, but I'm not sure what to say about that yet. In each case, I'm trying to figure out how this kind of language works, what its functions are, and what that can tell us about what we should do with it.
It was my Dartmouth colleague David Plunkett's work on metalinguistic negotiation that first got me thinking about the ways in which the language and concepts we use can be important to how we live and what we do and why. Shout-out to him—his work was part of what brought me to Dartmouth.