Who to get letters from for grad school applications?

In our newest "how can we help you?" thread, a reader asks:

I'm a student preparing to apply to PhD programs in philosophy. Many programs specify that they want letters of recommendation from philosophers. My question is: for the purpose of recommendation letters, who counts as a "philosopher"?

Does "philosopher" solely supervene over individuals with PhDs in philosophy? Would individuals with PhDs in, say, Ethics or Theology qualify? Does it matter if an individual with a PhD in these philosophy-adjacent fields teaches in a philosophy department, or publishes in philosophy journals? Or is this too far into the weeds, and students should ask the faculty most acquainted with their work and research capabilities to serve as recommenders?

Good questions. I'm not 100% sure, but I expect that admissions committees at philosophy PhD programs will want letters from people with philosophy PhDs who are able to comment in a well-informed manner on one's philosophical abilities and work. Although people in philosophy-adjacent fields (such as Theology) may be able to write on an applicant's general academic abilities and ability to put together well-reasoned work, my guess is that people on philosophy PhD admissions committees will be more likely to trust the judgment of someone who has a PhD and publishes in the field.

But these are just my thoughts. What are yours?

Comments

[Admission Committee Member]

I value letters from philosophers much more highly than non-philosophers. They have a better sense of the pool of candidates and present or at least past graduate students in philosophy. And they are more likely to be able to explain the student's work in ways that make it seem impressive to me. Empirically, they also seem to write more detailed letters. Often non-philosopher letters are, both, shorter and less dense with useful information. These factors are most likely to be present when the letter-writer both, teaches in a philosophy department and has a philosophy Ph.D.; but more likely to be present if the person is a philosopher in at least one of these senses, than if they are not a philosopher in either.

I think most of the people I've discussed this with would agree about the relative weighting of philosophers and non-philosophers. Some, however, maybe as many as half, are much less interested than I am in letters in the first place.

[East Coaster]

An anecdatum: I was admitted to very strong MA programs with my mixed letters (some philosophers, some not) but not to any PHD programs. I was admitted to strong PHD programs with my subsequent letters from philosophers. Obviously, more changed in the MA process than just my letter writers, but I figured I would pass that along.

[Possible List]

I suppose a rough ranking of possible letters you could get might be something like -

(1) philosophy faculty with a philosophy PhD who has taught you in multiple classes and was on an honors thesis committee or similar (so they've read substantial amounts of your work and revised versions of it)

(2) philosophy faculty with a philosophy PhD who has taught you in multiple classes and knows you very well

(3) philosophy faculty with a philosophy PhD who has taught you in one class but who still knows you very well

(4) philosophy faculty with a PhD in a different field but who is active in philosophy (e.g., presents at philosophy conferences, publishes in philosophy journals) who has taught you in multiple classes and knows you very well

(5) faculty in a closely adjacent field which is relevant to your philosophical interests who has a PhD in that field and whose work is philosophically relevant, who has taught you in multiple classes and knows you very well

(6) philosophy faculty with a philosophy PhD who has taught you in one class but will need help remembering who you are

(7) grad student/TA who is a PhD student in philosophy and who has taught you in multiple classes and knows you very well

(8) grad student/TA who is an MA student in philosophy and who has taught you in multiple classes and knows you very well

Would be curious what others think, but this is a rough pass at I would personally view them. I suspect, too, that which other letters one has will impact how a given letter is received (e.g., two glowing letters from philosophers who check all the boxes might helpfully contextualize/offset negative impressions of a third non-philosopher letter). I also suspect that junior/senior differentiations might make some differences around the relative merits of letters in categories (1) and (2), but it seems hard to parse at that point, and I think the quality and quantity of one's interactions outweighs most reputational differences among the letter-writers themselves.

I also think that the adjacent field in (5) being relevant to one's interests is important. I would understand the value of a letter from a physicist for a student interested in philosophy of physics. Or a letter from a classicist for a student interested in ancient. Or a letter from a French prof for someone interested in, say, Sartre. But if there isn't a clear alignment, I'd probably just wonder why the student couldn't get a letter from a philosophy faculty.

[Frequent Admissions Officer]

I basically agree with Possible List, except for items (5)-(7). I think a TA who's a Philosophy PhD student and knows your work well is far better than a professor who barely remembers you; that person's (inevitably) lackluster letter could harm your chances.

Also, though I can't say exactly why, some cognate fields are better than others. For more technically-oriented philosophy, for example, a glowing letter from a math or linguistics professor could help you a lot. So could a classicist for ancient philosophy.
But for ethics, aesthetics or political philosophy, a letter from a theologian or literature professor or, most of the time, political scientist will not help nearly as much.

(Come to think of it, I probably can guess why, but we don't need to get into all that here.)