Harlow Shapley probably said it best "A hypothesis or theory is clear,
decisive, and positive but it is believed by none but the man who created
it. Experimental findings , on the other hand are messy, inexact things
which are believed by everyone except the man who did the work." (reference
lost)
Ann Roe said" I think many scientists are genuinely unaware of the extent,
or even the fact of...personal involvement, and themselves accept the myth
of impersonal objectivity"
Einstein said in response to Heisenberg's assertion that only observable
magnitudes must go into a theory and that Einstein himself had stressed this
in formulating the theory of gravity : "Possibly I did use this kind of
reasoning but it is nonsense all the same. Perhaps I could put it more
diplomatically by saying that it may be heuristically useful to keep in mind
what one has observed. But on principle it is quite wrong to try founding a
theory on observable magnitudes alone. In reality, the very opposite
happens. It is the theory which decides what we can observe"