Gerhard Heinzmann

The 14th Congress of Logic, Methodology and Philosophy of Science will be held on July 19-26, 2011, in Nancy, France. In order to provide some historical background about DLMPS Congresses, we are honoured to have the opportunity to reissue a chapter of Anita Burdman Feferman and Solomon Feferman's Alfred Tarski : Life and Logic, dedicated to the early history of the DLMPS and the organization of the first Congress held in 1960 in Stanford. We are very grateful to the authors and the Cambridge University Press for their kind authorization to reissue this text.

ArgumentAccording to Hermann von Helmholtz, free mobility of bodies seemed to be an essential condition of geometry. This free mobility can be interpreted either as matter of fact, as a convention, or as a precondition making measurements in geometry possible. Since Henri Poincaré defined conventions as principles guided by experience, the question arises in which sense experiential data can serve as the basis for the constitution of geometry. Helmholtz considered muscular activity to be the basis on which the form of space could be construed. Yet, due to the problem of illusion inherent in the subject’s self-assessment of muscular activity, this solution yielded new difficulties, in that if the manifold is abstracted from rigid bodies which serve as empirical justification of the geometrical notion of space, then illusionary bodies will produce fictive manifolds. The present article is meant to disentangle these difficulties.