Recently I jumped, rather rashly, into a discussion about the purpose of philosophy. On his blog, philosopher Daniel Kaufman commented on the suggestion by a different philosopher that philosophy PhD students should be banned from publishing and took the opportunity to argue that there were too many PhDs hunting too many jobs, partly because graduate students were exploited as cheap labour, everybody was publishing too much, many of the leading philosophers weren't doing enough undergraduate teaching, and the field had gone down a dangerous and misguided path by assuming that it was a knowledge-generating exercise like science.
In Kaufman's telling, (a) philosophy does not generate knowledge ("these are not the sorts of questions that will ever admit of conclusive answers") but its purpose is to enrich our lives, (b) universities should fund things that enrich our lives even when they do not generate knowledge, and (c) admitting that philosophy does not generate knowledge is the best strategy for minimising future funding cuts, while trying to play scientist will backfire.
I could clearly have expressed myself better, especially in my first comment, but my position is that (a) philosophy can generate knowledge, (b) I do not see why universities should teach things that are self-admittedly non-academic, and (c) I strongly doubt that pitching philosophy as intellectually futile is going to work in its favour.
Note that I am not saying in any way whatsoever that universities should only train people for jobs, quite the opposite. I am merely saying that they are there to produce, manage and transfer knowledge (e.g. history of music or theory of music), while mere amusement or practical skills (e.g. appreciating music or learning to play the piano) are better accommodated in other ways, for example by buying a music CD or paying a private piano teacher. I am also not saying that anything that doesn't produce, manage or transfer knowledge is useless, merely that such a non-academic activity could perhaps better be accommodated outside of the university.
The main point I want to discuss now is, however, the first: can philosophy produce knowledge? The example that I would like to use is that of divine command theory and the Euthyphro dilemma. It may be said that that is very low-hanging fruit, but well, if somebody wanted to show how science can produce knowledge they would also choose something simple like the shape of the earth as opposed to the minutiae of population genetics or quantum physics.
As most people will know, divine command theory is the claim that "what is moral is determined by what God commands, and that for a person to be moral is to follow his commands" (quoted from Wikipedia, 11 Aug 2017). As most people will also know, Plato challenged this idea with the Euthyphro dilemma, which in modern terms is perhaps best summarised as follows:
There are two possibilities. Either the gods command that some action is moral because it is moral by an independent, objective standard. If that is the case, then we can cut out the middleman and conclude that morality does not actually flow from the gods. Alternatively, whatever random thing the gods declare moral is moral merely because the gods say so. If that is how it works, what if the gods commanded you to torture an innocent person to death? Clearly the first option is incompatible with divine command theory, but if the alternative is accepted then the theory is shown to have absurd consequences.
Religious people have, of course, tried to find answers to this dilemma. They seem to fall mostly into two categories, either stating that god would never command something evil, which even if they do not realise it grants that there is an independent standard and thus divine command theory is false, or claiming that the answer is "both", that there is no dilemma. As I have written on this blog before, that latter rebuttal does not work because both you can't avoid a bad outcome by accepting two bad options. If a judge asks whether you have murdered your neighbour or whether you got him killed through recklessness replying "both, your honour" won't clear you either.
I would consequently argue that Plato's philosophy has in this case generated a piece of knowledge: divine command theory does not work. And it was generated through philosophy as opposed to science, as no empirical data were involved.
What possible objections could be raised?
First, this is merely what we might call 'negative' knowledge. We still don't know what to base our moral reasoning on, merely that we cannot base it on "but the gods said so". To this I would respond that there is a clear parallel in science, which can also test and reject hypotheses and models but only ever tentatively (!) keep the ones that are currently not superseded and rejected.
Second, it could be argued somebody could find a solution to the dilemma or perhaps already has found a solution to the dilemma. Again the parallel to science should be clear: knowledge is always tentative until somebody comes along and disproves it and/or suggests an even better idea. The fact that we are never omniscient does not mean that we are as ignorant after somebody has thought through a problem as we were before.
Third, it could be observed that there are still plenty of people working as philosophers who accept divine command theory. And once more I would like to point towards the example of science. There are plenty of creationists, even some (if few) biologists; does that mean that biology does not produce knowledge? The only difference is that even the professionals in philosophy share less consensus on what is right than professional biologists.
Here I would argue that how much of a consensus can be achieved in a field depends on two main factors: whether the knowledge produced by the field is important in some kind of practice, and whether there is a lot of motivation to continue accepting a falsehood. Engineering, for example, has immediate and crucial practical applications. If an engineer accepts nonsense, they may construct something that fails embarrassingly, and consequently engineers are very likely to reject nonsense in their field of expertise (this qualifier is obviously important).
Economists, on the other hand, work in a field where things do not just work or fail, but they generally work in favour of either this interest group or that interest group. Even if raising wages would be "better" for the economy as a whole, it might still not be in the interest of individual investors; and even if lowering wages would be "better" for the competitiveness of an economy, it might still not be in the interest of an individual employee who wants more money now. It therefore seems entirely unsurprising to me that there would be a lot of motivated reasoning in economics, making it hard to discard false beliefs.
Philosophy has no immediate applications on the lines of keeping a bridge up, but it certainly deals with a lot of questions that are dear to people or affect closely held beliefs, for example ethics or epistemology. It therefore seems entirely unsurprising to me that the field would have it harder to discard false beliefs than chemistry or geography, for example. The take-home message here is that individual practitioners disagreeing does not demonstrate that there is no knowledge to be had; it may merely indicate that some practitioners reject that knowledge due to personal biases.
In conclusion, I remain convinced that philosophy does, or at least can, generate knowledge. It does so, among other approaches, by thought experiment, showing claims to lead to absurd consequences, or showing claims to involve a self-contradiction. Much of that may be rejection as opposed to proving of claims, but again, science is also mostly rejection of false ideas. The (always tentative) understanding we have now is what remained after myriads of mistakes were corrected.