Yazata - "It looks like the author is opting for an instrumental account of scientific theories, conceiving of them as calculating instruments that allow us to predict observations, rather than as true descriptions of the nature of the world such that it behaves as it is observed to do." Brucep - "What are you talking about?" I'm talking about what's traditionally been called "Saving the Appearances". It was a major issue in the Scientific Revolution. Yazata - " You could make the same kind of remarks about ancient and medieval cosmologies as well. Given enough tweaks in the form of epicycles and whatever, assuming the Earth as a fixed reference frame in the center of the observed universe enables observers to make very precise predictions of the movements of bodies in the heavens above as observed from the surface of the Earth." Brucep - "You can make such a claim but you don't know what you are talking about." http://www.polaris.iastate.edu/EveningStar/Unit2/unit2_sub1.htm Interestingly, the old Ptolemaic scheme remains so accurate in portraying the movements of the heavens that it forms the basis of planetarium projectors today. http://www.astronomy.ohio-state.edu/~dhw/A161/lecture5.html http://www.colorado.edu/philosophy/vstenger/Briefs/Copernicus &Galileo.pdf These lecture notes discuss saving the appearances. http://ocw.mit.edu/courses/science-...ll-2010/lecture-notes/MITSTS_003F10_lec17.pdf Osiander stated the issues neatly in his preface to Copernicus' De Revolutionibus - "The duty of the astronomer is to adopt whatever suppositions enable the motions to be computed correctly from the principles of geometry. These hypotheses need not be true or even probable. On the contrary, if they provide a calculus consistent with the observations, that alone is enough." The issue, as Exchemist and I tossed around earlier in the thread, is whether science should aim at truth or merely at usefulness. My observation in this thread is that the author of the OP seems to be arguing with Osiander that saving the appearances is enough. If Einstein's theories are consistent with a large body of observations now, they will presumably always be consistent with those kind of observations and hence Einstein will never be wrong. My observation was that the same thing can be said of Geocentric cosmology, but most scientists today stubbornly continue to believe that geocentric cosmology is fundamentally wrong. It may 'save the appearances', but it does so in a way that doesn't accurately depict what's actually happening in physical reality. Interestingly, this is an issue that currently plagues quantum mechanics, which possesses a mathematical formalism (actually more than one) that seemingly works very well in saving the appearances, but where there are multiple interpretations of what physical reality must be like on the microscale in order to make that so.