麻豆淫院

Caspar Hare is interested in your choices. Not the ones you鈥檝e already made, but the ones you will make, and how you鈥檒l go about making them. The more important, the better.

By way of example, suppose you鈥檙e deciding between two careers: journalism and physics. You enjoy both, but for different reasons: Journalism lets you interact with a broad swath of society, exercise your passion for writing and reach a wider audience; physics, though, represents the allure of science, with the freedom to chart a research trajectory at the forefront of human knowledge.

Suppose, too, for argument鈥檚 sake, that you had a pretty good idea of how each career would turn out. Either way, you鈥檇 be successful and recognized within your field. You鈥檇 live in a desirable location and make a good salary.

In your mind, the two options 鈥� call them J and P 鈥� are so equally and oppositely attractive that you truly cannot decide. But now suppose someone threw a third option into the mix: another journalism career, J*, identical to the first but paying an extra $50 a year. You probably prefer J* to J 鈥� why not? But do you prefer J* to P?

If you鈥檙e like most people, the answer is 鈥渘ot really.鈥� Fifty dollars a year is not enough to sway you between two choices that are so radically different. And yet this outcome poses a big problem for traditional theories of rationality. Hare, a newly tenured associate professor of philosophy at MIT, studies this problem, which is known to philosophers as 鈥渘egative intransitivity.鈥� And he鈥檚 had to make some career choices of his own along the way.

Incommensurate values

To understand negative intransitivity, first recall the transitive property: If you prefer A to B and B to C, then you prefer A to C.

Preferences that are transitive, Hare says, should also be negatively transitive, meaning that 鈥渋f you鈥檙e indifferent between A and B and indifferent between B and C, you should also be indifferent between A and C.鈥� But that鈥檚 not the case in the above example: Most people say they鈥檙e indifferent between J and P and also between P and J*, but they prefer J* to J. Does that make them irrational?

Not necessarily, Hare says; it just means that we need to augment our ideas about rationality.

鈥淚鈥檓 trying to expand the theory of practical rationality so that it applies to people whose preferences fall into that structure,鈥� he says. 鈥淲hen things like money are at stake, it鈥檚 fairly easy to represent preferences with numbers. But if other things are at stake, it鈥檚 not so easy. It鈥檚 particularly hard when the two things exemplify really different kinds of values 鈥� when they鈥檙e good in really different ways.鈥�

Hare thinks the key is to use not just single functions to represent preferences, but sets of functions, adding dimensions of complexity that will allow for multiple levels of comparison. Then, choices could be ranked based on the outcomes of all the functions in the set of functions that represent them. Though the modeling can get abstract, Hare says the focus is ultimately on applying the model to practical, real-world scenarios.

鈥淕iven that you have certain desires and certain beliefs, the idea that is you could use this [model] to tell you what you ought rationally to do in a given situation,鈥� Hare says.

Coming around to philosophy

So where did 鈥減hilosophy professor鈥� rank on Hare鈥檚 own list of career choices? Hare, who grew up in London, says for the first half of his life, it didn鈥檛 even occur to him.

鈥淚 was not a very academically inclined person at all. [As a teenager] I鈥檇 started reading some philosophy, but I never really associated it as something you did in school. In fact, it always seemed like the anti-school,鈥� Hare says, adding that he attended a 鈥渞igid鈥� boarding school that focused on tests and rote memorization.

鈥淧hilosophy seemed incredibly anarchic because you got to question the fundamental assumptions of all these disciplines,鈥� Hare continues. Still, he says it never crossed his mind to make philosophy 鈥渁 serious academic pursuit.鈥�

Even while attending Wesleyan University in Connecticut, Hare majored in intellectual history, but didn鈥檛 necessarily focus on philosophy. After a brief stint back in England working on the business end of the Financial Times, Hare, now 39, realized that he could turn his side interest into a career.

He returned to the United States to earn a master鈥檚 degree at Stanford University and a PhD at Princeton University, tackling problems in normative ethics and metaphysics. Hare鈥檚 first book, On Myself, And Other, Less Important Subjects (Princeton University Press, 2009), was a partial revival of the theory of solipsism, in which he claims that the fact that one鈥檚 own self has a special status in the world need not preclude us from making sound moral judgments involving others.

鈥楾here鈥檚 nothing you can鈥檛 think鈥�

Indeed, it鈥檚 this ability to reason about morality, instead of simply relying on emotional gut reactions, that Hare considers one of philosophy鈥檚 greatest offerings to the next generation.

鈥淲hat people, and young people in particular, think about moral questions is powerfully influenced by emotional responses that they have 鈥� in particular, disgust-related emotional responses, which are acquired via socialization,鈥� Hare says. 鈥淚t鈥檚 good for people to be able to step back and think about how to respond to a moralized case not by just saying, 鈥楬ow do I immediately feel about this? Does it set off my 鈥榶uck response鈥�?鈥� but knowing how to think carefully about it and really evaluate what鈥檚 going on.鈥�

At MIT, Hare enjoys teaching and working with students. Quite a few undergraduates take at least one philosophy class during their time at the Institute, he says, which he believes helps them learn to think in a 鈥渄isciplined way,鈥� no matter what their career path.

鈥淚n philosophy, there鈥檚 nothing you can鈥檛 think,鈥� Hare says. 鈥淓verything鈥檚 on the table, and the values are all about rigor and clarity, exploring how to use a thought and seeing where it goes.鈥�

---

This story is republished courtesy of MIT News (), a popular site that covers news about MIT research, innovation and teaching.