There’s a trivial answer to this, which actually has profundity. When I was a kid, I often wanted to run away from home but every time I tried, I found it very uncomfortable, so I came back. So I decided to run away in my imagination, and there at least the world was a very open place, since I had a stamp collection, which showed all these countries with a British monarch on their stamps, and it seemed to me that they all belonged to us, to me. My father worked as a foreman in the shipyards at Chatham, with its very strong naval traditions. We lived in Gillingham. Once every year during the War, we would be taken for tea in the dockyards, on a destroyer; the romance of the high seas and of empire left a strong impression. My earliest ambition was to join the Navy. So that even in the very gloomy days of 1946–47, just after the war, there was still an imaginary that encompassed this whole imperial world. Reading about it, drawing maps of it, became a childhood passion. Later, when I was in my teens, I cycled all over north Kent, getting to know a great deal about the geology, agriculture and landscape of our local area. I greatly enjoyed this form of knowledge. So I’ve always been drawn to geography. At school I was also strongly attracted to literature. When I got into Cambridge, which was still a bit unusual for a boy from my background, I took Geography rather than Literature partly because I had a teacher who had been trained in Cambridge, who made it clear to me that if you studied English there, you didn’t so much read literature as deal with F. R. Leavis. I felt I could read literature on my own, and didn’t need Leavis to tell me how to do it. So I preferred to follow the track of geography, though of course I never ceased to be interested in history and literature.

Geography was quite a big, well-established school at Cambridge, which gave a basic grounding in the discipline as it was practised in Britain at the time. I went on to do a PhD there, on the historical geography of Kent in the nineteenth century, focusing on the cultivation of hops. My first publication was actually in the house journal of Whitbread, the brewing concern—as a graduate student I earned a tenner for a piece published side by side with an article by John Arlott.

Explanation in Geography was looking for an answer to what I regarded as a central problem of the discipline. Traditionally, geographical knowledge had been extremely fragmented, leading to a strong emphasis on what was called its ‘exceptionalism’. The established doctrine was that the knowledge yielded by geographical enquiry is different from any other kind. You can’t generalize about it, you can’t be systematic about it. There are no geographical laws; there are no general principles to which you can appeal—all you can do is go off and study, say, the dry zone in Sri Lanka, and spend your life understanding that. I wanted to do battle with this conception of geography by insisting on the need to understand geographical knowledge in some more systematic way. At the time, it seemed to me that the obvious resource here was the philosophical tradition of positivism—which, in the sixties, still had a very strong sense of the unity of science embedded in it, coming from Carnap. That was why I took Hempel or Popper so seriously; I thought there should be some way of using their philosophy of science to support the construction of a more unitary geographical knowledge. This was a moment when, inside the discipline, there was a strong movement to introduce statistical techniques of enquiry, and new quantitative methods. You could say my project was to develop the philosophical side of this quantitative revolution.

By the sixties, it was connected here far more than anywhere else to planning—regional planning and urban planning. By that time there was a certain embarrassment about the whole history of empire, and a turning away from the idea that geography could or should have any global role, let alone shape geopolitical strategies. The result was a strongly pragmatic focus, an attempt to reconstruct geographical knowledge as an instrument of administrative planning in Britain. In this sense, the discipline became quite functionalist. To give you an indication of the trend, I think there are hardly any areas where, if you put the word ‘urban’ in front of research, you would say this is the centre of the field. Urban history is essentially a rather marginal form; urban economics is an equally marginal thing; so, too, is urban politics. Whereas urban geography was really the centre of a lot of things going on in the discipline. Then, too, on the physical side, environmental management is often about the handling of local resources in particular kinds of ways. So that in Britain, the public presence of geography—and I think it was quite strong—operated in these three particular areas; it wasn’t projected outwards in any grander intellectual formulation of the sort we might find in Braudel or the French tradition. You need to remember that for many of us who had some political ambitions for the discipline, rational planning was not a bad word in the sixties. It was the time of Harold Wilson’s rhetoric about the ‘white heat of technology’, when the efficiency of regional and urban planning was going to be a lever of social betterment for the whole population.

Well, my politics at that time were closer to a Fabian progressivism, which is why I was very taken with the ideas of planning, efficiency and rationality. I would read economists like Oskar Lange, who were thinking along these lines. So in my mind, there was no real conflict between a rational scientific approach to geographical issues, and an efficient application of planning to political issues. But I was so absorbed in writing the book that I didn’t notice how much was collapsing around me. I turned in my magnum opus to the publishers in May 1968, only to find myself acutely embarrassed by the change of political temperature at large. By then, I was thoroughly disillusioned with Harold Wilson’s socialism. Just at that moment, I got a job in the US, arriving in Baltimore a year after much of the city had burnt down in the wake of the assassination of Martin Luther King. In the States, the anti-war movement and the civil rights movement were really fired up; and here was I, having written this neutral tome that seemed somehow or other just not to fit. I realized I had to rethink a lot of things I had taken for granted in the sixties.

At that time, American universities were expanding their geography departments. Training in the discipline was much stronger in Britain than in the US, so there was quite an inflow of British geographers to fill the new positions. I had taught in the States on visiting appointments at various times, and when I was offered a job at Johns Hopkins, felt it was an attractive opportunity. The department there was interdisciplinary, combining Geography and Environmental Engineering. The idea was to put together a whole group of people from the social sciences and the natural sciences, to attack issues of environment in a multi-disciplinary way. I was one of the first to come into the new programme. For me, this was a tremendous situation, particularly in the early years. I learnt a great deal about how engineers think, about political processes, about economic problems: I didn’t feel constrained by the discipline of geography.

Hopkins is an extremely conservative campus, but it has a long history of harbouring certain maverick figures. For instance, someone who interested me a great deal when I first arrived there—his Inner Frontiers of Asia is a great book—was Owen Lattimore, who had been at Hopkins for many years, before he was targeted by McCarthyism. I spent a lot of time talking to people who were there about what had happened to him, and went to see Lattimore himself. Eventually I tried to get Wittfogel, who had been his accuser, to explain why he had attacked Lattimore so violently. So I was always fascinated by the political history of the university, as well as of the city. It’s a small campus, which has always remained very conservative. But for that reason, even a small number of determined radicals could prove quite effective—at the turn of the seventies, there was quite a significant anti-war movement, as well as civil rights activism around the university. Baltimore itself intrigued me from the start. In fact, it was a terrific place to do empirical work. I quickly became involved in studies of discrimination in housing projects, and ever since the city has formed a backdrop to much of my thinking.