Thread:User talk:Tmtoulouse/Bump: You know that obnoxious thing people do on the internet when they've said something and they feel they haven't been paid enough attention? I'm doing that./reply (43)

I have no problem with approaches which are genuinely part of science, as in required by and implied by science. But I can question whether the approach you've proposed is the only one which works with science. You claim science uses your interpretation of the principle of parsimony rather than some other - have evidence for that claim? You suggest that science only works with your interpretation of the principle of parsimony, and won't work with competing interpretations - have evidence for that claim?

I don't think science actually does use your principle of parsimony. Consider the theory of gravitation. Say we have Einstein's general relativity (hereafter GR), and we have some new theory, super-GR (maybe one of the GR alternatives listed by WP). Now, super-GR produces almost identical results to GR, except in very rare/extreme circumstances. Due to the rareity/extremity of those circumstances where super-GR behaves differently from GR, it is unlikely we will be able to distinguish super-GR from GR experimentally or observationally in the medium term. But, while Einstein's field equations are frequently lauded for their simplicity, super-GR's field equations are far more complicated. So, quite validly, physicists use the principle of parsimony to exclude super-GR: (1) GR and super-GR are experimentally/observationally indistinguishable at present; (2) GR is simpler than super-GR; (3) hence, prefer GR to super-GR. (Of course, maybe one day the experiments/observations needed to distinguish GR/super-GR will become feasible, and the results may actually favour super-GR. So, the rejection of super-GR by the principle of parsimony is provisional.)

Now, the reason I bring up this case, is that I think it demonstrates your account of the principle of parsimony - the "model element counting" approach you are using - doesn't match how scientists actually reason. GR and super-GR have the same elements in their model (spacetime, mass/energy, etc.). But super-GR's equations are much more complex than GR's. But I don't see how your model counting approach can measure the complexity of the equations, since all you do is count model elements. So, your definition of the principle of parsimony does not match the one actually used in science.

Moving on, let me produce two theories: theory 1: "The universe will instantaneously cease to exist this Friday". theory 2: "The universe will still exist this Saturday". Theory 2 is nothing more than the denial of theory 1. And what I've given is the whole of theory 1. There is no "Gargaturtle", no agent which ends the universe. The universe just ends for no particular reason. So these two theories have identical models. Hence, you can't use the principle of parsimony, as you describe it, to distinguish these two theories.