 The argument over the nature and role of conventions in science continued to the very end of Einstein’s life, reaching its highest level of sophistication in the exchange between Reichenbach and Einstein the Library of Living Philosopher’s volume, Albert Einstein: Philosopher-Physicist (Schilpp 1949). The question is, again, whether the choice of a geometry is empirical, conventional, or a priori. In his contribution, Reichenbach reasserted his old view that once an appropriate coordinating definition is established, equating some “practically rigid rod” with the geometer’s “rigid body,” then the geometry of physical space is wholly determined by empirical evidence: