Scientific knowledge is determined by scientific method. Prof. Richard Feynman, a Nobel Laureate in Physics, provided an incisive definition of scientific method:
“[W]e compare the result of [a theory’s] computation to nature, … compare it directly with observations, to see if it works. If it disagrees with experiment it is wrong. In that simple statement is the key to science.” The Character of Physical Law (1965), p. 150.