1 IntroductionIn 300 BC, Euclid presented 5 axioms believed to govern the properties of space[coxeter1989introduction]. For centuries, Euclid's geometry adequately described physical theories. Even though corroboriavilists and relationists disagreed about whether space was causal or not, there was agreement that Euclid's geometry was apt. However, in 1904, Einstein published his theory of special relativity (hereinafter referred to as SR). This could not be described by Euclidean geometry: it required a new way of thinking. The main solution was Minkowski geometry. I will discuss both geometries in this article and the extent to which Minkowski geometry is true geometry. I will then examine Poincaré's conventionalist perspective on the true geometry of the world, using the ideas of Einstein, Sklar, and Reichenbach to challenge Poincaré's view before concluding that, as Poincaré suggests, the geometry we use to describe the world does not matter.2 Euclidean geometry and relativity Although not the only geometry, Euclidean geometry had reigned in physics until the publication of Einstein's theory of SR in 1904. It was then that non-Euclidean geometries began to seem necessary to explain these new theories. Before the theory of SR, it was understood that the Newtonian view of space and time was correct [philosophy sklar1992]. From now on, Euclidean geometry could no longer explain the phenomena described by Einstein's theory. Minkowski's solution to the RS problem was to formulate a new geometry, which he published in 1907. Minkowski's geometry was undoubtedly not a geometry in the same sense as that of Euclid or Riemann (spherical) [ hartshorne2000geometry] for the moment four dimensions instead of three were...... middle of paper ......han Poincaré's convenience argument.5 Conclusion Poincaré, Einstein and Reichenbach each, for their own reasons , took the Consider that there is no real geometry. Poincaré in 1902, Einstein in 1921 and Reichenbach in 1927. Indeed, Poincaré's arguments in favor of the absence of true geometry were put forward before the publication of Einstein's special relativity, and therefore before the confusion of the Minkowski geometry is not introduced. But despite this, his reasoning was valid whether or not Minkowski's geometry was considered true geometry: for he considered geometry to be a mere matter of convenience. The author believes that, despite Reichenbach's reservations on the interpretation of conventionalism, Poincaré's argument remains true. There is no need for a posteriori knowledge to formulate a geometry, because we can manipulate laws to fit a geometry - we might just not like the result.!