How about the historian’s knowledge? How do we know what we know? Is it all just texts? Well, of course it’s all just texts – we deal with the written word, and little else. I thought about this a lot when I was writing my book on George Cheyne. How could I expect to get a handle on the life of an 18th century Scottish physician? I have always been bemused by the fact that Cheyne and I are physical opposites: he was huge, tall and over 400 pounds; I am not. I have always loved detective novels, and doing history is in some ways like solving a puzzle – except the pieces are scattered all over the place. In Cheyne’s case, I put together what he said publicly with what he said privately in correspondence. With that went what other people thought of him, publicly and privately. On top of that I looked at his setting – what was happening around him, the political and cultural milieu. I looked at his material circumstances, which I became very conscious of when writing for the Oxford DNB and looking at numerous wills. On the basis of all this, I came to some conclusions about what Cheyne was like, what he believed, and what it was like to live his life. Of course I could be all wrong, but that’s why history is an ongoing enterprise; it’s never finished. When I was in college I read Quentin Skinner’s essay on meaning and understanding in the history of ideas, and it made a deep impression on me. He argued that the text could not be separated from its context, that you had to have both to understand an idea. I could worry forever about the Russian doll of the reader reading the read text and what it means, if anything. I would rather assume that the writer (who in the 18th century, I think, was not as self-conscious as most writers today, except for Sterne) meant something and that maybe I can find out what that something is. It is true that I will never really “know” the eighteenth century, I will only know it from the twentieth. Since time travel is not yet a viable possibility, I guess that will have to do.