The attitude towards science today is rather prudent compared to how it has been in the past, or, as some might say, it is not as naive as it was, for it no longer considers science the proper guardian of the truth concerning nature or, more generally, concerning the different fields into which the domain of scientific investigation has expanded. We shall examine some of the reasons explaining the older attitude. In place of this once widely accepted point of view, one now finds another no less deeply-rooted perspective—among professional scientists as well as various cultivated people—namely, the belief that the assertions of science, though not deserving simply to be called true, must nevertheless be considered objective.