The first person to come to mind for me was Friedrich Ludwig Gottlob Frege who is famous for basically inventing symbolic logic (specifically, predicate logic with quantified variables). He spent an enormous amount of time working on the thesis that the results of mathematics flow rather directly from little more than the rules of logic plus set theory. He aimed to provide a constructive proof of this thesis.

Bertrand Russell discovered a logical flaw (now called Russell's paradox) in Frege's first book containing the constructive proof when the second book in his series was already in press and communicated it to Frege. Russell wrote of Frege's reaction in a bit of text I recall reading in a textbook on symbolic logic but found duplicated in this document with more details from which I quote:

As I think about acts of integrity and grace, I realise there is nothing in my knowledge to compare with Frege's dedication to truth. His entire life's work was on the verge of completion, much of his work had been ignored to the benefitof men infinitely less capable, his second volume was about to be published, and upon finding that his fundamental assumption was in error, he responded with intellectual pleasure clearly submerging any feelings of personal disappointment. It was almost superhuman and a telling indication of that of which men are capable if their dedication is to creative work and knowledge instead of cruder efforts to dominate and be known.

I don't think science generally lives up to its own ideals... but as I grow older and more cynical I find myself admiring the mere fact that it has those ideals and that every so often I find examples of people living up to them :-)