 The mere fact that a theory has survived the most rigorous empirical tests available does not, in the calculus of probability, predict its ability to survive future testing.Karl Popper used Newtonian physics as an example of a body of theories so thoroughly confirmed by testing as to be considered unassailable but were nevertheless overturned by Albert Einstein's bold insights into the nature of space-time.For the evolutionary epistemologist, all theories are true only provisionally, regardless of the degree of empirical testing they have survived.