In an earlier post, I claimed that one reason to study philosophy is that it teaches valuable skills. I supplied as a piece evidence for this view the fact that philosophy majors do better on post-graduate exams than almost every other discipline. Several departments have raised this point on their web pages as a reason to choose a philosophy major as well. However, one concern with claims of this nature is the possibility of selection bias. It could turn out that the reason philosophy majors do better isn’t because they learn skills in college, but that they have skills entering college which encourage them to choose philosophy as a major, and that these skills include doing well on these sorts of exams. Jason Brennan recently complained about the practice of using this as a basis for encouraging students to study philosophy on course web pages, claiming that without evidence against the possibility of selection bias, it is dishonest to suggest that philosophy teaches students these skills. The concern here is legitimate, and it is also important to know whether or not philosophy actually teaches students skills. So, is there any evidence showing that philosophy teaches skills instead of merely attracting the already skilled?
I think there is at least one way to test this. GRE and LSAT scores are a measure of a specific set of skills. Those skills are very similar to the skills one would need to perform well on SAT exams. So, one way to test whether there is improvement with respect to these skills is to see whether or not, as a group, people who study philosophy improve in their relative rankings compared to other departments from their average SAT scores to the average scores on post-graduate exams. When we look at this data, it suggests that the success majors have on these exams is causal. The mean SAT score for a student planning to major in philosophy or religious studies in 2013 was 1603. This was 10th overall among various groups of prospective majors (excluding those pursuing multiple majors). Despite a finer-grained division of majors, this ranking improves to 1st or 2nd annually among GRE scores. This suggests that philosophy doesn’t attract incoming students who are already ideally skilled to do well on these exams, but instead teaches students the skills they need to perform well on them.
As with all results, this data is open to alternative explanations. Perhaps the students who enter with a plan to study philosophy are very different from those who actually finish with a philosophy degree. Perhaps elite philosophy students are more likely to take these exams than elite students in other fields. But the most natural and initially plausible explanation for the data is that philosophy students learn the skills necessary to succeed on these exams. While this isn’t the only relevant issue to deciding what major to pursue, it should offset some concerns students may have that philosophy is an impractical discipline to study. It appears that philosophy really can prepare you to think and write effectively.