It is suggested that the existence of a preferred cosmological reference frame has a number of generally unrecognized implications which are by no means inconsistent with the assumptions and consequences of special relativity. Indeed, the assumption that there exists a cosmological fundamental reference frame for light propagation leads to an intelligible interpretation of relativistic effects and of the null observations of Michelson-Morley-type experiments. Hence all such experiments are impotent for the detection of any such fundamental frame, and it is shown (...) that this applies also to the ingenious coupled-mirrors experiment proposed by S. Marinov. Only astronomical observation allied to cosmological theory can reveal the existence of this frame. (shrink)