Euclidean Geometry before non-Euclidean Geometry

In [3], in my argument for the primacy of Euclidean geometry on the basis of rigid motions and the existence of similar but non-congruent triangles, I wrote the following: A: “The mobility of rigid objects is now recognized as one of the things every normal human child learns in infancy, and this learning appears to be part of our biological progaramming.” B. “. . . we are all used to thinking in terms of exact scale models, and this is true in every human culture of which I have ever heard.” Marcia Ascher (in private correspondence) suggested that these remarks are ethnocentric. I think I can justify the basic argument I was trying to make, but my argument appears to have been too simple. The purpose of this paper is to clear up this point. As an illustration of the difficulties, consider the following characterization of Western geometry and the Navajo conception of space from [2, pp. 157–163]: