From a recent contribution by Jason Brennan to the ongoing polemic between Michael Huemer and Kevin Vallier on the history of philosophy (as posted at BHL at 2:45 pm, February 11, 2020):
Context: Michael Huemer claims that the “great” philosophers are usually bad thinkers. They defend implausible ideas with bad arguments.
Vallier responds that the great philosophers are like architects. Their great achievement is that they build coherent systems of thought.
I’m not much convinced by Vallier’s response in part because, when I studied the history of philosophy or read papers in the field, it seems that the “greats” often have incoherent systems. A large number of published papers on the greats, and good number of the classes, take the form of “Great Thinkers says X here and Y here, but X and Y are seemingly incompatible. Let me try to figure out a way to spin X and Y to render then coherent.”
Don’t really see how the intended conclusion follows.
If X and Y are seemingly incompatible claims, then either they’re actually inconsistent or not. Either disjunct is possible.
Suppose not. Then if someone tries to “spin a story” making them consistent (aka “engage in scholarship”), then either she succeeds or fails.
Suppose she succeeds. Then she’s succeeded at resolving an apparent inconsistency. So the thinker is not incoherent, at least as far as X and Y are concerned.
Suppose she fails. It still doesn’t follow that she’s succeeded at demonstrating an actual inconsistency. She’s just failed at resolving an apparent but in-principle resolvable inconsistency. Same result as before.
If X and Y are actually inconsistent, it follows trivially that they’re inconsistent, and perhaps that the thinker’s system is incoherent (depending on the essentiality of X and Y to the system, a complicated issue of its own). But it’s an empirical matter whether that’s “often” so, and if so, how often. As far as I can see, the only empirical proof that would suffice is an enumerative (or quasi-enumerative) induction going through all of the relevant philosophers and all of their arguments. But I’ve never seen one, and doubt I ever will.
So I don’t share Brennan’s confidence in the conclusion: “the “greats” often have incoherent systems.” Even when they contradict one another, their systems may end up being internally consistent, or else involve large swatches of local consistency short of “incoherence.” In any case, there’s no clear inference from “there are apparent incompatibilities” to “there are actual inconsistencies,” much less good inferences mediated by the sheer fact that historians spend time and effort resolving the apparent inconsistencies.