As a matter of fact, it is comparatively easy to show that there are many more incidents of opposition to the progress of science on the part of scientists because of their conservatism, than on the part of ecclesiastics because of religion or theology. There has scarcely ever been a really important advance made in science, a really new discovery announced, which has not met with such bitter opposition on the part of the men who were most prominent in the science concerned at the time, as to make things very uncomfortable for the discoverer, and on many occasions this opposition has taken on the character of real persecution.
It will be at once said that this is very different from the formal condemnation by organized bodies of truths in science, with all that this implies of ostracization and of discouragement on the part of scientific workers. The history of science is full of stories showing that formal scientific bodies refused to consider seriously what were really great discoveries, or that scientific editors not only rejected papers representing valuable original research, but even did not hesitate to discredit their authors in such a way as to make it extremely difficult for them to pursue their studies in science successfully, and still more to prevent them from securing such positions as would enable them to carry on their scientific investigations under favorable circumstances. In a word, persecution was carried out just as far as possible, and the result was quite as much discouragement as if the opposition were more formal.
It is not hard to show, on the other hand, that while formal opposition by Church authorities was very rare, rejection by medical and scientific societies and by the scientific authorities for the moment of new discoveries was so common, as to be almost the rule in the history of progress in science.
James J. Walsh, The Popes and Science (1908)