Never does nature say one thing and wisdom another.

Good judgment and how things actually work do not finally disagree. When advice requires you to override every instinct, every signal from your body and every observable fact, the advice is wrong somewhere, however elegant it sounds. Anything genuinely wise tends to feel, in the end, like something you already half knew.

Use that as a rough test rather than a rule, since instincts get things wrong too. If a plan requires you to permanently ignore exhaustion, or to believe something you have never once seen happen, examine the plan. Wisdom should eventually fit the world you can actually see.