Appendix C - Memorable statements about the cosmological principle

Summary

This appendix is meant to pay justice to those authors who could see earlier than others that the FLRW models are an oversimplification of Nature. It contains a short (and very possibly incomplete) selection of quotations.

… the grounds on which homogeneity is generally assumed appearing to be those of convenience rather than generality … We must categorically dissent from the extreme idea … that homogeneity is included in the definition of the universe … We take it to be perfectly conceivable that an increase of telescopic power may reveal a variation of material density with distance, and the denial of this possibility … seems to us to be inconsistent with the fundamental principles of science. We hold that the assumption of spatial homogeneity is … a working hypothesis, valid so long as it does not conflict with observation or with theoretical probability, and justifiable during that time as a restriction on arbitrary speculation … we have no grounds for supposing that the part of the universe which is observed is typical of the whole … the phenomena we embody in our models may be purely local characteristics … while, in the present state of knowledge, a spatially homogeneous universe has greater claims to consideration than any other, such claims … have no a priori justification.

(Dingle 1933)