We give to much credit to predictions. Tocqueville has a single paragraph predicting that the two great powers in the future would be Russia and the United States. And he was right! For a while, at least. But people used this trivial sliver of his work to bolster his authority.
Similarly, Marx and Malthus made some terribly wrong predictions, which has undermined their authority among a lot of people. In the case of Marx, I am tempted to say, good. Anyway, other thinkers have pulled out the more valuable ideas. Malthus's mistakes certainly led to a lot of insights by later demographers and economists.
So predictions don't matter that much. The search for authority is a distraction from taking ideas seriously. Still, this is a good shocker from the Marquis de Custine:
"If ever they should succeed in creating a real revolution among the Russian people, massacre would be performed with the regularity that marks the evolutions of a regiment. Villages would change into barracks, and organized murder would stalk forth armed from the cottages, form in line, and advance in order…"
The Empire of the Tsar, p. 293.