Philosophically, the phenomenon external to an area of interest affects what goes on in the inside; a sufficiently common occurrence as to warrant being called the second law of geography.

Later restated in his 2004 article in Annals of the Association of American Geographers, 94:2 "On the First Law of Geography: A Reply" | The 1999 International Journal of Geographical Information Science article is generally cited as the first instance of Tobler's second law of geography within the body of literature.