Philosophical differences: What does physics tell us about the real world?

IN COLLEGE, PROFESSOR OF PHILOSOPHY Hans Halvorson was dismayed by the idea of having to choose between science and the humanities, so he blazed his own path, combining philosophy with physics and mathematics.

Why are philosophers fascinated by science? As a cultural phenomenon, we cannot ignore the power of science. It has transformed our world into what we know today. But I believe it is not the only source of knowledge. A lot of what we know comes through ordinary life experiences.

What questions are you working on? I’m interested in what physics tells us about the real world. There are two opposing views. One view is that our theories perfectly describe the reality we see around us — this is known as realism. But there are many cases where what we thought we knew from science turned out to be wrong, for example when Einstein’s theory of relativity trumped the Newtonian view of space and time. The opposing view is called antirealism, and says that physical theories are good at making predictions that we can use in our technologies, but they do not describe reality. I take the view that there must be something right on both sides, and that there may be a way to translate one view to another. A question I am looking at now is whether two competing theories of the structure of the universe, string theory and quantum loop gravity, have a common core.

How does your training help you think about these ideas? My Ph.D. dissertation was on the foundations of quantum mechanics. But I wanted to do something new, and I was fortunate to receive an Andrew W. Mellon Foundation award that enabled me to spend a year at the Mathematical Research Institute at the University of Utrecht in the Netherlands learning an area of mathematics known as category theory. Now I am applying these concepts to the philosophy of science and the debate between realism and antirealism.

How is this of value to the public? I think part of my job is to help people understand how science fits into their lives, especially in the United States where there is tension between science and religion. I understand the difficulty of reconciling beliefs with what we learn from science. But it is also not good to just believe what science says, because it is always changing. Science is full of unknown discoveries.

–By Catherine Zandonella