In what aspect of Einstein’s theory were there any assumptions that were not true? A theory in physics is a detailed explanation of why things are as they are and that allows for accurate predictions to be made. If any prediction is found to not be true than there is something wrong with the theory and it needs to be modified. For over 100 years Einstein’s theory has been tested over and over and not a single prediction has failed the test. This week the theory’s prediction that large gravitational bodies “bend” light will be tested again. And the total solar eclipse will with almost 100% certainty be confirmed again. Newton’s theory of gravitation is not based on any incorrect assumptions. It is mathematically accurate, as is Einstein’s theory. Mathematics is the universal language of science and its theories. A theory in science is not a guess. Darwin’s theory of natural selection was not based on inaccurate guesses. It was based on factual observations. What it lacked at the time was the explanation for the mechanism of natural selection: what was the cause of the differences in traits and how were those differences stored and passed on? Today we know that DNA in genes can change (mutate) leading to changes in traits that may be selected for or against, i.e., increasing or decreasing the likelihood of a gene being passed on. Nothing in Darwin’s theory was based on a falsehood. An incomplete explanation yes, but nothing in the theory needed to be corrected, just expanded. The laws of the universe, such as the laws of gravitation or thermodynamics, etc., are immutable. Human laws are not. That’s why human laws lack the 100% predictably of settled scientific theories.