Page "Philosophy of space and time" Paragraph 36

The position of conventionalism states that there is no fact of the matter as to the geometry of space and time, but that it is decided by convention.

The first proponent of such a view, Henri Poincaré, reacting to the creation of the new non-euclidean geometry, argued that which geometry applied to a space was decided by convention, since different geometries will describe a set of objects equally well, based on considerations from his sphere-world.