Matthew McGrath joined Washington University as a professor of philosophy this fall. From knowing your COVID status to identifying pileated woodpeckers, in this Q&A McGrath unpacks the interesting questions around how we know what we know about the world.
Have you always wanted to be a philosophy professor? How did you get started?
I discovered philosophy as a freshman at Notre Dame, having planned to major in math. I loved it right away. You got to think rigorously about all those questions you always wondered about but never had time to look into: Is there a God? Is right and wrong just a matter of our preferences? Is the mind reducible to the body? After getting my first job in philosophy, I began to move more squarely into epistemology, or the study of knowledge and related phenomena such as rational belief and evidence. Epistemology asks what knowledge is, how it is possible, and what makes it important. Since reading Descartes my freshman year, I’ve found epistemology gripping. Who couldn’t be gripped by the challenge in his first Meditation of how one could know one isn’t dreaming or deceived constantly by a malicious demon? We do know it. But it’s a challenge to say how.
I feel grateful to be able to spend my days thinking, talking, and writing about philosophy. And I realize there is something peculiar about it. Ludwig Wittgenstein remarks in On Certainty: “I am sitting with a philosopher in the garden; he says again and again “I know that that's a tree,” pointing to a tree that is near us. Someone else arrives and hears this, and I tell them: “This fellow isn't insane. We are only doing philosophy.”
As someone immersed in epistemology, how would you describe what it means to have knowledge?
Most philosophers think of knowledge as something like true belief backed with good (enough) reasons. Plausibly, one needs good reasons in order to have knowledge. But how good do the reasons have to be?
Here philosophers have struggled to explain what makes reasons good enough to support knowledge. I think we can make progress on this question by thinking about what knowledge is good for. When you know something, you can rely on it, not merely in your thought but in what you do, in your planning, and in your emotional life. You can “count on” what you know. For example, if you merely think you are Covid-negative, you can’t properly base your actions and plans on your being Covid-negative. But if you know that you’re Covid-negative (say from a negative test result), you can.
The intriguing thing is that if this idea is correct, then it’s hard to avoid a certain peculiar consequence — namely that whether you know can depend on the practical stakes, and therefore that the pragmatic encroaches on knowledge. A lot of my work, including my book with Jeremy Fantl, Knowledge in an Uncertain World, concerns how to navigate these issues.
Most philosophers think of knowledge as something like true belief backed with good (enough) reasons. Plausibly, one needs good reasons in order to have knowledge. But how good do the reasons have to be?
One interest of yours has been the nature of appearances. What is the relationship between how things appear in our heads and what’s really out there in the world?
I think there is a familiar notion of appearance — of how things look, sound, feel, how things seem — that isn’t a matter of what happens in my mind or yours or anyone else’s. And we often know such appearances. For instance, I know what pileated woodpeckers look like. What I know, when I know this, isn’t a fact about myself or my mind, or about your mind. Pileated woodpeckers would look the way they do regardless of what goes on in our minds. It’s a fact about pileated woodpeckers that they look a certain way. Good birders can come to know this fact through observation of the birds, not through introspection.
None of this is to say that if something looks like a pileated woodpecker, it must be one. Even if appearance is out there in the world — as the look of the woodpecker is — it doesn’t follow that what has the appearance associated with a certain type of thing must belong to that type of thing. But appearance, too — in this common sense of ‘appearance’ – is a feature of the nonmental world.
As autobiographical aside: I was inspired to think about the possibility that appearances are out there in the world by my twin sons, as children, debating over whether a bird they saw in our backyard looked like one kind of bird or another. It struck me that they were not arguing over what is in their minds but a feature of birds. Ten years later my sons are entering first-year students at WashU. One of them is a founding member of the WashU Birding Club.
What questions excite you right now?
I’ll mention just one: suspension of judgment. If you suspend judgment on a hypothesis, you neither believe it nor reject it. But suspending judgment isn’t merely an absence. A rock neither believes nor rejects the claim that the earth is round, but the rock of course isn’t suspending judgment. Is suspending judgment a matter of believing you don’t know whether the hypothesis is true? Again, this seems insufficient: you can believe that you don’t know without suspending judgment. If someone asks me something about Canadian hockey scores circa 1975, I’ll know I don’t know the answer. Since I really don’t care, I’ll just drop the issue entirely and give it no further thought. Intuitively, I’m not “suspending” anything in doing so.
The position I’m developing is this: suspending judgment is an active, agential phenomenon. It is the intentional delaying, deferring, or putting off of judgment. By suspending judgment, we can curate our beliefs. When we do this well, we improve our beliefs, by “holding off” from accepting a hypothesis on tempting but weak evidence until and unless better evidence comes in. When we suspend poorly, though, we hold off when we shouldn’t, as when the climate skeptic demands too much evidence in order to allow himself to believe in climate change.
What do you enjoy so far about being at WashU?
I’m overjoyed to be teaching such bright and engaged undergraduate students, and I’m looking forward to teaching our strong philosophy graduate students in the spring. The philosophy department and the interdisciplinary PNP program offer me many opportunities for productive collaboration. But I know I can learn a lot about issues relevant to philosophy from many other people at WashU outside Wilson Hall. I especially look forward to getting to know and talk to other scholars at WashU.
