Abstract
‘If a man will begin with certainties, he shall end in doubts; but if he will be content to begin with doubts, he shall end in certainties' (Bacon 1605). Four centuries later, one of the greatest of contemporary philosophers — Sir Karl Popper — has consistently maintained that knowledge advances by refutation of false doctrines and not by verification of true ones (which, indeed, can never be completely verified). ‘Error is unavoidable; it can be rational, and when responsibly made and honestly reported, is not even culpable’ (Laor 1985).
The desire to verify an hypothesis rather than to seek to refute it can be responsible for the suppression of deviant data. There is a fine distinction between bias, which may afflict honest investigators, and fraud, which is always dishonest. Even a true statement can be tainted by bias, and Ronald Fisher concluded that Mendel's published figures on the genetics of peas were so close to the expected ratio of 3:1 that it would have taken ‘an absolute miracle of chance’ to produce them (Hamblin 1981).