In the last chapter, I asked a number of questions about doing philosophy historically. I asked how this enterprise works: how one goes about assessing a philosophical picture by tracing its development through time. I also asked whether this enterprise is concerned with arguments, whether it is rational, and whether it aims at truth. But there is an important question I have not yet asked: should we do philosophy historically? Do we have good reasons to engage in this enterprise? Is it, perhaps, one that we must engage in? If so, why? These are obviously important questions. If we cannot explain why, or whether, we should do philosophy historically, then it is hard to see why we should care about this enterprise, or read the work of those engaged in it. But these questions are also important for another reason. Since at least the early nineteenth century, some philosophers have argued that philosophy is an essentially historical discipline. Doing philosophy, they claim, is inseparable from studying its history. Charles Taylor calls this view “the historical thesis about philosophy.” Despite the prevalence of the historical thesis, however, it is notoriously difficult to explain just what it means, or why one might accept it. As a result, the last two centuries have been marked by what Gary Gutting calls a “tedious and inconclusive debate over whether philosophy is essentially historical.”

I want to show that there is a better way of understanding this debate.