Physical theories in a multiple possible-world environment

Abstract

In the paper here abstracted, the author submits to critical analysis the criteria of truth used in physical theories and physical laws, with reference to some theories in contemporary physics allowing for the existence of multiple universes. Seeing as the properly done inquiry demands universe models with diverging basic principles (the laws of physics), two theories have been chosen as the object of the present study: the first one which assumes eternal inflation and the second one presupposing string cosmology (a string landscape). Both theories admit a broad variation in physical laws (which may amount to fundamentally different laws or to the same basic principles only slightly modified). Magnitude of dark energy (the cosmological constant) has been taken to represent the parameter of a physical law that changes its value from one possible universe to another. The analysis of physical theories admitting multiple universes shows that the standard requirements for a theory, which have their origin back in early modern period and which assume the validity of a theory to depend on its conformity to the criteria of observability and justification of the fundamental principles of our universe, cannot be entirely consistent. The tendency in the development of theoretical physics is towards creating the models which represent increasing (in many cases apparently altogether insurmountable) difficulty for experimental verification. It can be argued that, for some physical theories, there obviously must be no verification requirement at all, since any assumption of the necessary correspondence between theory and reality is no more than a manifestation of anthropocentrism. A theory may be able to reveal a more general ground which will be beyond the scope of observation. In this case, an epistemological question will arise, what can be the criterion of validity for such a theory? The present paper is an attempt to provide arguments for the priority of mathematical over the empirical justification.