This is the quote that Jung uses to open Symbols of Transformation:

It is a moral duty for the man of science to expose himself to the risk of committing error ...

Those endowed with a mind serious and impersonal enough not to believe that everything they write is the expression of absolute and eternal truth will approve of this theory, which puts the aims of science well above the miserable vanity and paltry amour propre of the scientist.

-- Ferrero, Les Lois psychologiques du symbolisme

It's much easier to say those words than to believe them.