In his monograph Theory of Relativity Based on Physical Reality, Hungarian physicist Lajos J?nossy develops the complete Einsteinian formalism of relativity theory by analysing the process of measurement, the systems of measures created in this process and experimental data expressed in terms of measures. He demonstrates that based on a simple principle (which he calls the Lorentz principle) and its generalization the whole formalism of the original theory may be developed in conformity with the notions of common sense without mathematizing physical reality, so that the new way of development is of the same heuristic power as the original one. His analysis makes it clear that the allegedly revolutionary new notions of space and time follow not from physical experiences but from Einstein's positivist philosophical commitments. Having established the place and role of a privileged (but not absolute) reference system, at the second level of his theory J??nossy connects this system to the carrier of electromagnetic phenomena which he also assumes to be the carrier of the gravitational and other physical fields. Although he uses the term 'ether', he explicitly rejects the old theories of this entity and attributes to it dynamic properties. In the last section of the paper Einstein's and J??nossy's ether concepts are compared and it is argued that despite the parallelism between the two concepts, from J??nossy's point of view Einstein's ether is too mathematical to cure the inverted relation between mathematics and physics characteristic for Einstein's relativity.
In the fifth and early sixth decades of the last century several significant works were published on the philosophical background and epistemological limits of physical cosmology such as Bondi?s epistemological discussion in the first chapters of his Cosmology , Dingle?s paper in Vistas in Astronomy or Harre?s analysis in the British Journal for the Philosophy of Science. In the light of the intensive development of relativistic cosmology following the discovery of the cosmic background radiation in 1964, such works may seem outdated, and the problems raised by them have actually been forgotten or suppressed by the community of philosophers and physicists alike over the last decades.