The besetting sin of able men ...

The besetting sin of able men is impatience of contradiction and of criticism. Even those who do their best to resist the temptation, yield to it almost unconsciously and become the tools of toadies and flatterers. \
The besetting sin of able men is impatience of contradiction and of criticism. Even those who do their best to resist the temptation, yield to it almost unconsciously and become the tools of toadies and flatterers. "Authorities," "disciples," and "schools" are the curse of science and do more to interfere with the work of the scientific spirit than all its enemies.

Quotes from the same author

If the perpetual oscillation of nations between anarchy and despotism is to be replaced by the steady march of self-restraining freedom, it will be because men will gradually bring themselves to deal with political, as they now deal with scientific questions.
No delusion is greater than the notion that method and industry can make up for lack of mother-wit, either in science or in practical life.
Perhaps the most valuable result of all education is the ability to make yourself do the thing you have to do, when it ought to be done, whether you like it or not. It is the first lesson that ought to be learned and however early a man's training begins, it is probably the last lesson that he learns thoroughly.
There is nothing of permanent value (putting aside a few human affections) nothing that satisfies quiet reflection--except the sense of having worked according to one's capacity and light to make things clear and get rid of cant and shams of all sorts.
Follow humbly wherever and to whatever abyss Nature leads, or you shall learn nothing.