One factor that contributed to a new understanding of the history of science was the
replacement of Newtonian physics by Einstein’s theory of relativity. Before this replacement,
it was generally thought that science prior to the 17th century was bad science
simply because it gave the wrong answers to scientific questions, and that part of the
achievement of the scientific revolution–part of what constituted it as a revolution–was just
its coming up with true science rather than false science. When Newtonian physics was
superseded, this attitude could no longer be maintained. It was not just that Newtonian
physics turned out to give the wrong picture of the world; it was that this wrong picture
could not be blamed on bad science.Newtonian physics was thoroughly confirmed by
rigourous experiment for two hundred years, encountering no serious difficulties until the late nineteenth century. The success of seventeenth-century science could no longer be put
down to its having achieved the right description of the world, and, conversely, giving the
wrong description of the world could no longer be used as a reason for dismissing pre-
Newtonian science. A common medieval understanding of science as having the purpose
of ‘saving the appearances’, that is, giving a theory that would predict all observed phenomena
but that would not claim to actually give a description of reality, gained
plausibility as a result of this change, since it offered a way of explaining how Newton was
a great scientist despite his theory not being correct. (This idea was not in fact original to
the Middle Ages, since it was proposed by Ptolemy.)