As a philosophy tutor and candidate at Harvard, I can say that philosophy has many roles and does many things. One role is that it is the most fully general subject area, encompassing many kinds of thinking and cultures. The depth and breadth of philosophy as an undergraduate major or gradudate discipline will take you far.
One of the United States’ great 20th Century philosophers, Wilfrid Sellars, said: “The aim of philosophy, abstractly formulated, is to understand how things in the broadest possible sense of the term hang together in the broadest possible sense of the term”. This means that the relationship between electromagnetic fields, the dynamics of tectonic plates, sexual selection, efficiency in farming methods, the history of feudalism, and a human tendency to seek each others’ praises, if any there be, falls within the purview of philosophy.In order to carry out such generalist ambitions, ideally, a philosopher would have expert knowledge in every field and discipline there is.
Indeed, the greatest “philosophers” of the ages were actually polymaths who made numerous contributions to many fields: Aristotle, Descartes, Leibniz, Hume, Kant, Mill, and Russell, et al. It is not reasonable for most of us to aspire to such heights. Still, the more one can combine familiarity with numerous fields along with considerable knowledge of one or more (non-philosophical) subject matters, the better. Let me address the significance of striking a balance between breadth and depth for one’s aspirations for philosophy graduate school and, ultimately, a career in philosophy.
All academic fields are becoming increasingly specialized.
The growth of knowledge combines with increasing competition for jobs to promote the rise of experts on ever more narrow topics. Philosophy has increasingly joined these trends. Many now specialize in technical sounding things like “supervenience”, “the grounding relation”, and “external reasons”. But many specialties require considerable knowledge of other fields. Philosophy of mind is increasingly impossible these days without significant attention to what is going on in the psychological and neurological sciences. Philosophers of language need to know a lot of linguistics, epistemologists need to be familiar with probability theory and Bayesianism as well as various fields in psychology, ethicists need to know about the psychology of moral judgment, philosophers of science need to be familiar with trends in methodology across scientific disciplines.
So, what does this mean for an undergraduate considering graduate school or staring to embark on a graduate school application?
As a philosophy student and tutor, the first thing to remember is to discuss your particular area of interest in graduate school application because this will show that you have made efforts to increase your knowledge and skill in related areas outside of philosophy.
This at least means taking courses in such areas. If it makes sense for the best writing sample you can submit, showing that you can appeal to non-philosophical sources, skillfully interpret them, charitably critique them, etc. in your work would also potentially bestow an advantage.
Of course, no one will hold you to all the same interests you had as an undergraduate once you are in a doctoral program. But whatever direction your interests take, you can expect to need to either take courses in the topic or do a lot of self-tutoring to get up to speed. For a long time, many graduate programs required study in a language that would be necessary for serious scholarship of historical figures. Many are now giving the alternative option of taking courses that are of relevance to your speciality or dissertation topic.
So depth in a particular topic, both in and out of philosophy, is necessary in the contemporary profession. Furthermore, it is a check distinguishing dilettantism from genuine polymathic ability. It is a rare philosopher that does not itch to weigh in on issues outside of her specialty. But first demonstrating the ability to contribute to a deep and complex debate with mastery of the literature is far more likely to get one taken seriously when later testing the waters on a new issue.
None of this, however, should detract from the grand vision of philosophy articulated by Sellars above. If philosophy cannot be a home for integration of knowledge and investigation of cross-disciplinary relationships, what can be?
So philosophers need to continue to cast their nets as widely as possible. And this requires qualities and habits that inspire and sustain philosophy in the first place: insatiable curiosity mixed with skepticism about appearances and easy answers, tenacious researching and note taking, and the willingness to go the extra step to gain more than a superficial acquaintance with a topic. Finally, it requires creativity and willingness to venture outside well-worn grooves. History has shown that most philosophical speculations will be relegated to the dustbin. But that doesn’t mean the speculations weren’t worthwhile at the time or that there weren’t lessons drawn from them. And good philosophical speculation requires wide-ranging breadth in as many areas of knowledge as possible.