Source Of Error Quotes (2 quotes)
Besides accustoming the student to demand, complete proof, and to know when he has not obtained it, mathematical studies are of immense benefit to his education by habituating him to precision. It is one of the peculiar excellencies of mathematical discipline, that the mathematician is never satisfied with à peu près. He requires the exact truth. Hardly any of the non-mathematical sciences, except chemistry, has this advantage. One of the commonest modes of loose thought, and sources of error both in opinion and in practice, is to overlook the importance of quantities. Mathematicians and chemists are taught by the whole course of their studies, that the most fundamental difference of quality depends on some very slight difference in proportional quantity; and that from the qualities of the influencing elements, without careful attention to their quantities, false expectation would constantly be formed as to the very nature and essential character of the result produced.
In An Examination of Sir William Hamilton’s Philosophy (1878), 611. [The French phrase, à peu près means “approximately”. —Webmaster]
When experimental results are found to be in conflict with those of an earlier investigator, the matter is often taken too easily and disposed of for an instance by pointing out a possible source of error in the experiments of the predessessor, but without enquiring whether the error, if present, would be quantitatively sufficient to explain the discrepancy. I think that disagreement with former results should never be taken easily, but every effort should be made to find a true explanation. This can be done in many more cases than it actually is; and as a result, it can be done more easily by the man “on the spot” who is already familiar with the essential details. But it may require a great deal of imagination, and very often it will require supplementary experiments.
From 'August Krogh' in Festkrift Københavns Universitet 1950 (1950), 18, as cited by E. Snorrason, 'Krogh, Schack August Steenberg', in Charles Coulton Gillispie (ed.), Dictionary of Scientific Biography (1973), Vol 7, 501. The DSB quote is introduced, “All his life Krogh was more interested in physical than in chemiical problems in biology, and he explained his critical attitude thus.”
In science it often happens that scientists say, 'You know that's a really good argument; my position is mistaken,' and then they would actually change their minds and you never hear that old view from them again. They really do it. It doesn't happen as often as it should, because scientists are human and change is sometimes painful. But it happens every day. I cannot recall the last time something like that happened in politics or religion.
(1987) -- 
