I had lunch today with a friend whose daughter is planning to major in philosophy, with minors in religious studies and classics. My reaction was to say (to my friend's horror), "Sounds like she could be on the path to becoming a right-winger."
My reasoning is that those are areas of study where one learns critical thinking. Critical thinking is necessary, although not sufficient, for being able to understand the role of freedom and markets.
Also, that combination of major and minors show a willingness to grapple with ideas with little need to follow the crowd. That, too, is a necessary condition for becoming a libertarian, given that the crowd is caught up in national socialism.
I have more hope for someone who majors in philosophy than for someone who takes freshman economics.
Presumably Arnold's hypothetical philosophy major doesn't take freshman economics, or this wouldn't be a very interesting claim!
Question for Arnold: If you're right, why are there so few libertarian academic philosophers? And why do economists across the political spectrum have so much more appreciation for the benefits of markets than the general public, the typical college grad, or the typical philosopher for that matter?
Speaking as an undergraduate econ major/philosophy minor, I'd say that studying philosophy typically leads not to "willingness to grapple with ideas," but to blanket skepticism. Feel free to consider me the exception that proves the rule.