Is "known" a correct word choice in the following?
It has long been known that Fruit A contains an enormous amount of vitamin C. However, recent research has disproved this conventional wisdom.
By describing something as "known," the speaker is committed to its truth. By saying it has been "disproved," the speaker is committed to its non-truth. To acknowledge something is a truth and has been disproved is a gross incompatibility in the speaker's belief, isn't it?
I'd appreciate your help.