On the First Law of Geography: A Reply

D aniel Sui has sent me a written version of comments presented by five geographers at a panel on the first law of geography organized by him at the 2003 AAG meeting in New Orleans. The comments seem to fall into two camps: some reject the idea of ‘‘laws’’ in geography, and others feel that my notion has been of some merit. Interestingly, several other laws are cited in the comments; two by Isaac Newton (gravity, motion), two additional ‘‘first’’ laws (ecology, social science), four additional laws applying to people (utility maximization, primate city, human behavior, and Gresham’s), and three ‘‘second’’ laws (thermodynamics, spatial heterogeneity, things are never equal—the last two being only suggestions). Curiously, they do not mention other well-known laws, such as those of Zipf (1949), or Ravenstein’s (1885) 10 laws, or a second law of geography by proposed by Arbia, Benedetti, and Espa (1996) and one by myself (Tobler 1999, 87). The comments then focus on three topics. One is a discussion of what constitutes a law, and whether ‘‘the first law of geography’’ fits into the appropriate definition. Much of the remaining material examines the concepts of ‘‘related’’ and ‘‘near.’’ Smith is quite correct in pointing out that this discussion would never have taken place if the specific word law had not been used. And Barnes is also correct when he puts it into context and observes that, by restricting myself to local effects, I used the notion to parse the possible complexities of simulating urban growth. I am a great believer in simplicity, when this is possible. For example, the point in science is to achieve as many results as possible with the fewest hypotheses. So, in order to simplify the problem of depicting the growth of population in the Detroit region, I tried to eliminate complicating factors. This is when I invoked ‘‘the first law of geography: everything is related to everything else but near things are more related than distant things.’’ Doing this allowed me to concentrate on local effects— using the idea of a change in the ‘‘unit inhabitant,’’ and ignoring many other possible influences. As a result, Miller calls my simulation effort ‘‘crude,’’ whereas Barnes considers that it invokes complex ideas. Miller would undoubtedly consider economics, transportation, geology, and other factors to produce a much richer, but also more involved, model. Curiously there is no discussion of other concepts from the 1970 paper.