Declinism

Scholars point out that strains of declinism can be found in most eras of history, which raises the question, is it logically possible for the world to be going to hell interminably — to be endlessly on its way to hell, ever worse than before, and ever better at each earlier epoch?

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Laudably, he [Cullen Murphy] ends on some optimistic notes, and some prescriptions, rather than wallowing in declinism.

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So maybe declinism is just a quirk of human psychology.

Source: wiktionary

Instead, declinism ruled—the belief that Britain was in a state of terminal, irreversible decline being widely shared, and—as glam has demonstrated—frequently and forcibly expressed.

Source: wiktionary