Incidentally it is evident from this that Newton «fudged» his reported observations to fit his theory of deriving the law of universal gravitation from Kepler's data reduction, but Newton couldn't have known that the indeterminate errors of observation propagated in a systematic was (joannenova.com.au)
The whole point is you don't accept anything without proof, if tomorrow someone comes up with a better model of universal gravitation then we move to that model. (religion.blogs.cnn.com)
The simpler Newton's law of universal gravitation provides an accurate approximation for most physical situations. (religion.blogs.cnn.com)