Q&A: Genesis 6:5 — 'every intention of the thoughts of his heart was only evil continually' — describes mankind as thoroughly corrupted, whether read hyperboliclaly (extreme wickedness) or literally (total moral collapse)

Mike is willing to entertain whether the phrase is hyperbolic or literal. If hyperbolic, it means man was astonishingly wicked — even his desires were evil, not just his acts. If literal, it means the moral fabric of society had completely deteriorated. He notes there may be a Calvinist subtext to the question (total depravity) that he does not have space to address fully.