It is just not true that there are as many opinions as philosophers.
Philosophy is often accused of never making progress, always asking the same questions in endless circles. And a popular view is that when philosophers disagree on something, there will be n+1 opinions being put forth about whatever subject matter, where n is the number of philosophers opining about it.
I am in the process of answering the first charge by way of a book that will hopefully be published by the University of Chicago Press next year, so stay tuned. As for the second, the following two-part essay attempts to answer it by way of, gasp!, data. In particular, data from a highly informative survey of what professional philosophers think, carried out by David Bourget and David Chalmers .
In order to appreciate my comments below, however, I have to briefly explain that I think philosophy moves in a series of conceptual spaces (as opposed to, say, the empirical space which constraints the advancement of science), where philosophers produce and then analyze a number of “peaks” representing useful frameworks for thinking about a given problem. For instance, if the problem is “how should we behave toward each other?” the three major peaks (Nicholas Rescher, in a 1978 paper, called them “aporetic clusters” ) currently on the market are Kantian-style deontology, utilitarianism, and virtue ethics. There are other peaks as well (e.g., ethics of care), and there are sub-peaks or clusters within the major ones (e.g., Aristotelian vs Stoic virtue ethics, or act vs rule utilitarianism). Philosophical scholarship, I submit, is about finding (or constructing) these clusters, exploring their consequences, and refining them over time.
So, we that in mind, let us look at the Bourget-Chalmers’ paper in some detail. As I said, it is quantitative in nature, and despite a number of possible reservations about its methodology (e.g., concerning the sampling protocol, or the fact that the multivariate analyses presented in it are rather preliminary and should really have been much more the focus of attention) it represents a rare opportunity to systematically assess the views of an entire academic profession. This is the sort of thing that would probably be useful also in other disciplines, from the humanities to the natural sciences, but is all too seldom actually done.
The first thing to note is that the data definitely disproves the above mentioned caricature of extreme disagreement among philosophers (the “n philosophers have n+1 opinions” shtick). Consider some of the main findings of the Bourget-Chalmers survey:
- 71% of respondents thought that a priori knowledge is possible, while only 18% didn’t think so (the remainder, here and in the other cases, falls under the usual heterogeneous category of “other”). There is a clear majority here, despite ongoing discussions on the subject.
- However, things are more equally divided when it comes to views on the nature of abstract objects: Platonism gets 39% while nominalism is barely behind, at 38%. Superficially, this may seem an instance of precisely what’s wrong with philosophy (can you imagine physicists being similarly split about the value of string theory? Oh, wait…). But in fact this sort of result is perfectly congruent with my model above of philosophy moving in a in conceptual space characterized by multiple peaks: Platonism and nominalism are two such peaks in the conceptual landscape pertinent to the ontology of abstract objects. There simply isn’t an ascertainable fact of the matter about whether Platonism or nominalism is “true.” They are both reasonable ways of thinking about the ontology of abstract objects, call them frameworks or, my favorite term, accounts (I don’t think people should use the word “theory” in philosophy, it feels too sciency…).
- It isn’t uncommon these days to hear that W.V.O. Quine demolished once and for all the distinction between analytic and synthetic propositions, one of his famous “two dogmas” of empiricism . Well, the bad news for Quine is that about 65% of practicing philosophers disagree, and only 27% agree that such demise has in fact taken place.
- One of the most lopsided outcomes of the survey concerns what epistemic attitude is more reasonable to hold about the existence and characteristics of the external world: 82% of respondents qualified themselves as realists, followed by only 5% skeptics and 4% idealists. See, even philosophers can agree on something!
- Most philosophers are atheists (73%), which, by the way, is a significantly higher percentage than most categories of scientists .
- Classical logic, for all the newer developments in that field, still holds sway at 52%, followed by non-classical logic at 15% (though there is a good number of “other” positions being actively debated, in this case).
- Physicalism is dominant in philosophy of mind (57%), while cognitivism seems the way to go concerning moral judgment (66%).
- In terms of ethical frameworks, things are much more evenly split, with deontology barely leading at 26%, followed by utilitarianism (actually, its broader version, consequentialism) at 24% and virtue ethics at 18%. Here too, as in the case of Platonism vs nominalism, the result makes perfect sense to me, as it is hard to imagine what it would mean to say that deontology, for instance, is the “true” approach to ethics. These three (and a number of others, see above) are reasonable, alternative ways of approaching ethics — and there are a number of unreasonable ones that have been considered and discarded over time (Randian Objectivism?).
- In philosophy of science, realism (i.e., the idea that scientific theories describe ontologically “thick” unobservables out there, like electrons) beats anti-realism (i.e., the view that scientific theories are empirically adequate, but that they do not commit us to any strong ontology), by a large margin, 75% to 12%, which is consistent with my own view (I’m a philosopher of science!) that, although anti-realists do have good arguments, the preponderance of considerations clearly favors realism.
- And finally (although there are several other entries in the survey worth paying attention to), it turns out that correspondence “theories” of truth win out (51%) over deflationary (25%) and epistemic (7%) accounts.
Bourget and Chalmers then move on to consider the correlations between the answers their colleagues provided to the questions exemplified above and other, possibly influential, factors. Here too, the results are illuminating, and comforting for the profession, I would say.
For instance, there was practically no correlation at all between philosophical views and gender, with the glaring (and predictable, and still relatively small) exception of a 0.22 correlation (which corresponds to barely 5% of the variance explained) between gender and one’s views on Philosophy of Gender, Race, and Sexuality.
Although the authors report statistically significant correlations between philosophical views and “UK affiliation, continental European nationality, USA PhD, identification with Lewis, and analytic tradition … [and] … USA affiliation and nationality, identification with Aristotle and Wittgenstein, and a specialization in Continental Philosophy,” these are all below 0.15 in absolute value, which means we are talking about 2% or less of the variance in the sample. (In statistics, the variance explained is the square of the correlation coefficients; since the latter varies between 0 and 1, the variance explained is smaller than the correlation.)
There just doesn’t seem to be much reason to worry that philosophers are characterized by wildly different views depending on their gender, age, or country of origin — as it should be if philosophy is a type of rational inquiry, rather than just a reflection of the cultural idiosyncrasies of its practitioners.
Next, we’ll look at even more interesting correlations emerging from the Bourget-Chalmers study, as well as to a synthetic, multivariate picture of their survey data. Stay tuned.
 What Do Philosophers Believe?, by D. Bourget and D.J. Chalmers, Philosophical Studies 3:1-36, 2013.
 Philosophical disagreements: an essay toward orientational pluralism in metaphilosophy, by N. Rescher, Review of Metaphysics 32:217-251, 1978.
 Two Dogmas of Empiricism, by W.V.O. Quine, The Philosophical Review 60:20-43, 1951.
 Scientists are still keeping the faith, by E.J. Larson and L. Whitam, Nature 386:435-436, 1997.
MASSIMO PIGLIUCCI IS THE K.D. IRANI PROFESSOR OF PHILOSOPHY AT THE CITY COLLEGE OF NEW YORK. HIS BACKGROUND IS IN EVOLUTIONARY BIOLOGY AND THE PHILOSOPHY OF SCIENCE, THOUGH HE HAS RECENTLY DEVELOPED A KEEN INTEREST IN STOICISM. HIS MOST RECENT BOOK (CO-EDITED WITH MAARTEN BOUDRY) IS “PHILOSOPHY OF PSEUDOSCIENCE: RECONSIDERING THE DEMARCATION PROBLEM” (UNIVERSITY OF CHICAGO PRESS, 2013). HIS OTHER WRITINGS CAN BE FOUND AT PLATOFOOTNOTE.ORG.