Does philosophy make progress? Daniel Stoljar, professor of philosophy at Australia National University, thinks it does, and he defends that idea in his new book, Philosophical Progress: In Defence of a Reasonable Optimism. In the following guest post,* he presents one kind of argument for his view.

How Philosophy Makes Progress:

On The Identity of Philosophical Problems over Time

by Daniel Stoljar

The much-discussed (and much worried about) question of whether there is progress in philosophy is highly sensitive to how we understand the identity of philosophical problems; that is, when we have one such problem and when we have another. If you assume that many problems discussed today are identical with those discussed in the past, pessimism is almost inevitable. But if you reject that assumption, optimism is much more plausible. It is partly because I reject that assumption that I defend optimism in this book.

To illustrate, consider the mind-body problem, and, in particular, consider two famous presentations of that problem: Frank Jackson’s ‘Epiphenomenal Qualia,’ the classic 1982 paper in which he set out the well known Mary thought experiment, and Descartes’s Meditation VI, where he discusses the real distinction between mind and body. Are the problems presented here the same or different?

The identity view (as we may call it) says they are the same: the same problem is present in these discussions, even if in some hard to understand way its outer clothing is different. The alternative view says they are different, though they might be related in interesting ways. Indeed, on this view, to use phrases like ‘the mind-body problem’ and ‘two famous presentations of that problem’ is to use a misleading, though perhaps unavoidable, way of speaking.

The identity view makes pessimism almost inevitable. After all, Jackson’s problem is an open question; philosophers of mind are currently discussing various answers to it, and no consensus has been reached. If it is an open question, however, and if it is identical to Descartes’s problem, then Descartes’s problem must be open too. But if that is an open question, the history of the mind-body problem is the history of an open question with no progress being made. Again, pessimists or people worried by it say repeatedly “in philosophy people continually disagree about the same old problems.” If ‘same’ here means ‘identical,’ as it presumably does, we have the identity view.

The identity view makes pessimism almost inevitable, but doesn’t quite entail it. In principle, you can be making progress on a problem without having solved it. You might be moving towards a solution, for example, without having arrived at one. Or you might be developing a better understanding of possible solutions, without deciding among them. Or you might be opening up new vistas of inquiry, just as Justin Weinberg suggests here. Still, while all this is true, it is hard to shake the feeling that progress of this sort is not quite what we are searching for when we search for progress in philosophy. For in other fields, while progress of this sort certainly happens, a much more straightforward sort happens too, or any rate so people often think: what happens is you solve one problem, and then move onto others. If the identity view is true, nothing like that happens in philosophy.

But suppose now we reject the identity view. Then the issue of progress looks completely different. For one thing, if Jackson’s problem and Descartes’s problem are distinct, it doesn’t follow that the latter is open if the former is. Hence the simple argument for pessimism I just set out goes away. Moreover, if they are distinct, it is open to us to argue that Descartes’s is a solved problem, even if Jackson’s is not. And if that is so, we may begin to see discussion of the mind-body problem over the years as in many ways like discussion in other fields: earlier problems raised and solved, contemporary problems still wide open.

That’s what happens anyway if the problems are distinct, and if the earlier one is solved—to what extent are these things plausible? While the issues are complex, I think we can see that they are plausible without going too far into the details. First, an essential assumption in Descartes’s problem is (to put it simply) that matter is extension in space. That assumption is what entitles him to claim a clear and distinct idea of what matter is, and, in turn, to argue for the distinction between mind and body. But no such assumption is essential to Jackson’s problem, which is a very good reason for thinking that the problems are distinct. Second, the assumption that matter is extension is false; at any rate, in the light of philosophical and scientific developments after Descartes, nobody now accepts it, at least as he intended it. If so, and if the assumption is essential to Descartes’s problem, we may well regard that problem as solved, even if Jackson’s is not.

To say that the problems are distinct in these ways is not to deny they are related. Jackson’s problem is formulated in the knowledge of Descartes’s, for example, but not vice versa; to that extent, the later problem is a successor of the earlier one. And both problems are on the same general topic or subject matter, namely, the relation between the mind and body. This is a topic that many people in many different times and cultures have been interested in, just as they have been interested in other topics of philosophical concern. But Descartes and Jackson are asking different questions about this topic. And that Descartes’s question is answered does not mean the topic itself goes away.

In sum, if we reject the idea that many philosophical problems raised today are identical to those raised in the past, we have available to us an optimistic picture of progress in philosophy very different from the common pessimistic one. On the pessimistic picture, philosophy is a locus of endless disagreement over identical questions. On the optimistic picture, people at different times ask different but related questions, and moreover earlier questions have often been answered.

All this assumes a lot about the case of mind and body, of course, not least that it is a typical piece of philosophy. In the book I argue it is typical, or at any rate that we find the same pattern in many other cases. But I don’t doubt there is much more to say, and I’d be very interested to know if others see something similar in their own sub-fields of philosophy.

Art: Paul Gauguin, self-portraits, 1888-1897