Popper believed that there was a contrast between the theories of Sigmund Freud and Alfred Adler , which he considered non-scientific , and the revolution set off by Albert Einstein 's theory of relativity in physics in the early 20th century . Popper thought that Einstein 's theory , as a theory properly grounded in scientific thought and method , was highly " risky " , in the sense that it was possible to deduce consequences from it which differed considerably from those of the then-dominant Newtonian physics . The theory of relativity was partly confirmed by Eddington 's experiments in 1919 . In contrast he thought that nothing could , even in principle , falsify psychoanalytic theories . He thus came to the conclusion that they had more in common with primitive myths than with genuine science
experiments in 1919
Solar eclipse of May 29, 1919
Karl Popper