Princeton Weekly Bulletin April 19, 1999
No definitive answers
Introduction to Metaphysics and Epistemology draws 200 undergraduates
By Caroline Moseley
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Gideon Rosen lecturing to students
of metaphysics and epistemology in McCosh 50
(photo by Denise Applewhite)
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And about 200 undergraduates flock to each lecture to be confused, stymied and frustrated, and maybe, just maybe, gain insights into the nature of Life and Truth. Whether the topic is the concept of God, the problem of evil, or free will and determinism, "These are issues that everyone is in a position to worry about," observes Rosen.
Those who insist on incontrovertible answers to hard questions should reconsider their expectations, says Rosen. "At the beginning of the course, I say, 'We're looking for good arguments.' What's a good argument? It's one where the premises are acceptable, and the conclusion is probable.
"Then we talk about what 'probable' means. It's one thing to ask how probable it is to get two sixes in a row when you're rolling dice. It's another to ask how probable it is that God exists."
What is a good argument?
Rosen defines epistemology as "the philosophical study of knowledge and reasonable belief. What is a good argument, and how good does it have to be? The 18th-century philosopher David Hume pointed out that science is based on a potentially fallible inference from the data. No matter how careful you've been in making your observations, it's always logically possible for your conclusions about the future to be false. The sun has risen every day in your experience, and you infer that it will do so tomorrow, but it may not."
As they study epistomology, Rosen says, students begin to realize that "if absolute certainty is your standard, practically none of your beliefs are reasonable. The trick in epistemology is to identify a standard for reasonable belief that is not hopelessly stringent, that allows some things but not others."
Metaphysics is "the philosophical account of what the world is like, what there is," he explains. "Nowadays, science has taken over some of the issues, but metaphysicians still discuss such questions as, Is there a God? Is there something more to the world than physical reality? If that's true, there's a lot more to the world than science suggests, and we look at the arguments surrounding that sort of inquiry."
Students discuss, for example, the rationality of religious beliefs -- a question that combines elements of metaphysics and epistemology. "We talk about what is known as Pascal's Wager (after Blaise Pascal, 17th-century philosopher and mathematician). Pascal's argument is, 'Never mind whether or not there is evidence for the existence of God; it's in your interest to believe, because what if God does exist?' You're betting on the best way to live your earthly life. The question is, What's the expected gain to you?"
Rosen believes Pascal's Wager to be "the earliest application in philosophy of a calculus of probability to a decision problem." It has become part of the main tradition of philosophy "because it treats an intellectual question -- What should I believe? -- as a practical question -- What should I do? What is in my best interest?"
Don't believe what you read
In addition to assigning the works of philosophers from St. Anselm (1033-1109) to Princeton professors Bas van Fraassen and David Lewis, Rosen posts extensive lecture notes on the course Web site at www.princeton.edu/~grosen /pucourse/phi203/main. shtml. These notes reflect upon the readings and lectures. Rosen cautions students, "Don't mistake my glosses on the texts for the texts themselves. Your job is to argue with what's on the page in order to figure out whether it's right. Don't believe what you read."
He admits that "you could spend a lifetime talking about any one of these philosophical issues. Philosophy is not just an endless series of questions without answers, but you can be reasonably certain that any answer you do obtain will be controversial. There's little consensus about anything in philosophy."
Indeed, Rosen tells his students, "One of the most important lessons you should learn from this course is that in philosophy there are no experts." This comes from someone who is himself a noted metaphysician, epistemologist and philosopher of mathematics, author of A Subject With No Object: Strategies For Nominalist Reconstrual in Mathematics (written with J. Burgess, 1997).
How did Rosen wander into these intellectual thickets? As an undergraduate at Columbia University, "I was going to be a biochem major," he says. "I took a course in the philosophy of science, and all of a sudden in philosophy class it seemed I might actually have something to say. All the questions are so open."
Surprise the professor
Rosen found in the philosophy department a home for "my natural tendency to resist and object. There's not a lot of point in resisting or objecting in biochemistry," he observes. "But in philosophy, you might actually surprise the professor." He went on to earn his PhD at Princeton in 1992.
A member of the faculty since 1993, Rosen has himself been pleasantly "surprised" from time to time. He cites one example.
"There's a stage in the argument about the value of believing in God that says, 'Look, the value to me of believing God exists is infinite, so it doesn't matter how unlikely it is; an infinite quantity multiplied by even the smallest fraction is still an infinite quantity.'
"Well, that's true if you're using ordinary mathematics, but there is a nonstandard way of treating the problem using the theory of surreal numbers, devised by [Professor of Mathematics] John Conway. If you use surreal numbers as the probabilities in Pascal's Wager, the argument isn't straightforward at all. A student of mine who was also taking a seminar with Conway discovered this exception and told us about it. It was a real Princeton moment."