Abstract
The relation between environment and social groups of men is the main theme of human geography, and there are three theories of environment;
(1) The theory of decisive environment workcd by Ratzel (2) The theory of relative environment worked by Blache and (3) The theory of sudjective (constituent) environment. The first presupposes the theory of Darwin and Lamark, and stands upon the mechanical view of nature. The second presupposes the theory of pre-adaption. The last reo gnizes the power of creating environment which the central being of the environment possesses, and also recognizes the history of natural environment, which is the part of central being and is quite different from social group but has a kindred relation to it.
We propose that this thing which unites social group and natural environment together and forms the territory should be our idea of social group used in human geography.
If we call the customary geography based on the theory of relative environment human geography, we might call the one thus based on the theory of constituent environment social geography.
