One question is whether there has been progress in commonsense thinking (or folk psychology as it is called most of the time), which I discussed last week. A different question is, whether there has been progress in philosophy, a question that has also been the subject of quite a bit of philosophical debates and that has been discussed by some of the most prominent thinkers, like Ludwig Wittgenstein, Karl R. Popper and Thomas S. Kuhn. In this blog I’ll not try to answer this question, but I want to talk about one important aspect of it: whether there is a received body or “hard core” of philosophical knowledge.
Progress is a relative matter in the sense that things are compared “before” and “after”. So we must have something to compare and what we want to compare must be viewed at several moments in time. Without any further discussion, I think that we can say that in the “hard” sciences like physics, chemistry and biology there is a core body of knowledge that is generally accepted and that has been growing through the years. But how about philosophy? Does it have a received body of knowledge?
In 2009 David J. Chalmers and D. Bourget made a list of thirty central themes in philosophy and asked via a survey academic philosophers – mainly in the field of analytic/Anglocentric philosophy – what their positions on those themes were. There were some 2000 recipients of the survey and 47% filled it in and sent it back. The outcome? It’s not unexpected, and actually it was what everybody who knows a bit about philosophy could tell you, but from the point of view of the hard sciences it’s somewhat shocking: There is no hard core of philosophical thinking. Maybe the conclusion is a bit too hard, for if you look closer you may find some points about which all philosophers agree (but I guess that they are rare), but on almost any theme in the survey philosophers are divided. I’ll not go into the details what all the terms that follow mean, but here are some examples, and if you only take a look at the division of the percentages, you’ll see that there is no unanimity among the thinkers (you can find the full list in Chalmers article below):
- free will: compatibilism 59%, libertarianism 14%, no free will 12%, other 15%
- mental content: externalism 51%, internalism 20%, other 29%
- normative ethics: deontology 26%, consequentialism 24%, virtue ethics 18%, other 32%
- truth: correspondence 51%, deflationary 25%, epistemic 7%, other 17%
Etc.: On almost all 30 themes the philosophers who filled in the survey disagree to an important extent on what “the facts” are. Only on one theme more than 80% agreed: On the question whether there is an external world, for 82% of the philosophers asked think that the outside world “really” exists. Three views (namely that there is a priori knowledge; atheism; and scientific realism – saying that the world is as described by science) attracted over 70% support. Three more views got more than 60% support. On all the other 23 questions the philosophers disagreed in a more or less stronger way.
What to say more? I think that the conclusion is clear. Philosophers disagree on almost any issue that is important for them and there is no hard core of philosophical thinking. Is it surprising? No, of course, for what should philosophers philosophize about when they agreed?