3) I am keen to use the word “models”, because all of this talk about the validity of different scientific theories can get very complicated – even when dealing with what we usually call the hard sciences. It seems clear that the simple theory that objects of differing mass will fall at the same speed (in a vacuum, i.e. to account for wind resistance due to the shape of an object) is readily verified wherever one may be on earth. As to exactly how this happens – and for what reasons – more can, and has been said, and here, of course, we get into more abstract notions and interpretation (often involving complex mathematics, calculus, etc.). More complex and robust theories are not as straightforward for the common man of course, as again, they require much more background knowledge, abstract and critical thinking, and hence, more interpretation. (in Isaac Asimov’s view, “once scientists get hold of a good concept they gradually refine and extend it with greater and greater subtlety as their instruments of measurement improve. Theories are not so much wrong as incomplete… Copernicus switched from an earth-centered planetary system to a sun-centered one. In doing so, he switched from something that was obvious to something that was apparently ridiculous. However, it was a matter of finding better ways of calculating the motion of the planets in the sky, and eventually the geocentric theory was just left behind. It was precisely because the old theory gave results that were fairly good by the measurement standards of the time that kept it in being so long.”). When considering the great scientific theories of Newtonian mechanics, Maxwell’s theory of the electromagnetic field, special and general relativity, and quantum mechanics, for example, this is certainly the case. The validity of these complex and broadly-encompassing theories, rest in large part on repeating highly controlled experiments successfully from various angles, as well as the theory’s overall explanatory power (of the evidence we find) and ability to make useful and testable predictions (as the well-known philosopher of science Karl Popper points out, theories help us to see new problems where none have been seen before and also help us to find new ways of solving them) – and there is of course, their corresponding usefulness for applications in the real world (which often takes some imagination, of course). However, I think it is reasonable, and perhaps even obvious, to submit that as regards scientific theories vis a vis general or ordinary knowledge (like the fact that you and I can agree it is raining outside, or that objects of varying mass fall at the same speed), matters of proper interpretation of the world we experience can become more tenuous as one moves up in levels of critical reflection, context, generalization, extrapolation, and abstraction – and even more so when we are dealing with models.
The second half of this show is helpful: http://www.bbc.co.uk/programmes/b00vhhjm