There are basically two ways to do philosophy. One is to try and produce original solutions to philosophical problems, solutions you intend to be superior to those that came before then. We might call this philosophy by innovation. The other way to do philosophy is by analyzing the arguments of other philosophers, often by showing how the ideas of one philosopher resolve a problem raised by another, or raise problems for a solution proposed by another. We might call this philosophy by synthesis.
The question then is which is better, innovation or synthesis? Now by raising this question I don’t mean to ask about how it is best to learn philosophy. Obviously learning how to understand arguments and how to use the ideas of other philosophers is essential to everyone’s formal philosophical training. What I mean to ask is which is the better method by which to move philosophy as a whole forwards.
Now if we examine the most influential and important works of philosophy it would seem that philosophy by innovation is better. It is rare that a paper considered truly influential is an example of philosophy by synthesis. The truly influential papers are influential because they have proposed compelling new ideas or raised new problems, and philosophy by synthesis is unlikely to produce such a paper.
But it is possible that looking at things in this way is misleading. Perhaps most of the work was really done by the unremembered papers, done in the style of philosophy by synthesis, which paved the way, so to speak, for the more celebrated paper. If this were the case then philosophy by synthesis would be the real core of philosophical progress, with philosophy by innovation simply the visible manifestation of that progress.
Unfortunately I am not a historian of philosophy so I can’t speak definitively about the above hypothesis. But it strikes me as highly unlikely. But before we run in too many circles perhaps I should point out that the idea that one of the two ways of doing philosophy I have presented here is superior and should be pursued exclusively is a confused way of looking at the problem, and that if we view it in this light we are unlikely to make much progress. It is much more likely that the two complement each other, such that philosophical progress wouldn’t occur without both ways of doing philosophy. Of course this doesn’t resolve the issue, we still want to know which one is more important, in the sense that we want to know which one we should devote more time to.
So what contributions do they each make to philosophical progress? Philosophy by innovation obviously is responsible for introducing new ideas into philosophy. And obviously without new ideas philosophy can’t move forward. Philosophy by synthesis on the other hand seem responsible for evaluating those new ideas. As I see it philosophy by synthesis plays new ideas off against old ones, and against their rivals, and after enough papers are written one solution to the philosophical problem in question begins to seem like the best. (Although there will always be some who dissent.) So pursing only philosophy by synthesis would result in the discipline standing still. But pursuing only philosophy by innovation would result in too many new ideas. Every philosopher would have their own system and there would be no way of telling which are the best solutions without reading them all. This would make extending and improving the best ideas in new ways (often the best way of doing philosophy by innovation) basically impossible. And this would make progress, or at least recognizable progress, nearly impossible.
Obviously I prefer philosophy by innovation, since I rarely engage in philosophy by synthesis here. There are two reasons for this. One is that philosophy by synthesis is only valuable when read by other philosophers, who can use it in order to evaluate which philosophical positions are worth paying the most attention to. Since this blog isn’t read by any professional philosophers (although it is read by a few grad students), as far as I know, philosophy by synthesis would be largely wasted. However, new ideas are valuable regardless of who reads them (assuming that they eventually end up published in some form that will get read by the professionals), and so it seems better to do philosophy by innovation. But secondly I think that philosophy by synthesis, at least in its current form, can eventually be done away with. It is my opinion that it is possible to develop methods by which philosophical theories can be evaluated on their own merits, without having to compare them to other theories. Such methods would eliminate the need for philosophy by synthesis (although papers would still have to be published applying these methods to the various new ideas). Thus I am motivated to try and develop such evaluative methods, itself a project best categorized as philosophy by innovation, rather than in engaging in philosophy by synthesis.
Of course none of this really answers the original question; but I don’t really have an answer to the original question. At best I can say that as much philosophy by synthesis should be done as is required to generate some kind of consensus regarding the current theories developed by philosophy by innovation. But I don’t know how much philosophy by synthesis is required to get to such a consensus. On the other hand, if we had a way to evaluate philosophical theories on their own merits then only two or three papers would have to be written per innovative philosophical theory. Which I think makes developing such methods very attractive, since it takes a lot of philosophy by synthesis to generate any kind of consensus, certainly much more than two or three papers per theory.