Freud gives an example of how the lever of sentiments shift the balance once more, and indeed on the very issue of whether knowledge formulated in a scientific manner can lead mankind to saner and more rational conduct.
In 1929, the same year in which the optimistic manifesto of the Vienna Circle was published, Sigmund Freud, writing in the same city, produced a book of his mature years, giving his somber and pessimistic answer.

To the founder of psychoanalysis, the role of science in our culture had been a continuing preoccupation, and in 1911 he had still been optimistic enough to sign the Aufruf of the Society for Positivistic Philosophy.
But in that book of late 1929, “Das Unbehagen in der Kultur”, Freud found that science, while counting among the most visible manifestations of civilization, was at best an ameliorating influence in a titanic struggle on which the fate of our culture depended.
That struggle, he said, was centered on mankind’s often-doomed effort to master “the human instinct of aggression and self-destruction.” Even at that time he saw, in the last paragraph of the book, that “Mankind has gained control over the forces of nature to such an extent that with their help it may have no difficulty to exterminate one another to the last man.”
That is Gerald Holton’s interpretation in his essay “What Place for Science in our Culture at the End of the Modern Era?”
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