What does Proverbs 26:11 mean?

Earlier proverbs noted that wise people learn from observation, including their own failures (Proverbs 9:9; 19:25; 24:32). Those who lack godly wisdom and sense (Proverbs 1:7; 3:5–8) typically need to suffer more before they learn a lesson (Proverbs 14:3; 26:3). Even when actions lead to consequences, they may repeat the exact same mistakes. Solomon uses a nauseating illustration to make this point. Dogs should realize that whatever they ate made them sick, yet they are infamous for putting what's been expelled right back into their stomachs. People rightly find that disgusting, and wise people should be repelled at the idea of learning nothing from a mistake, only to repeat it.

Somehow, a fool keeps doing the very thing that harms him. This can lead to addiction and dependency which are then even harder to overcome. The apostle Peter applies this proverb to those who are warned about godly truth and turn back towards sin (2 Peter 2:21). He writes: "What the true proverbs says has happened to them: 'The dog returns to its own vomit, and the sow, after washing herself, returns to wallow in the mire'" (2 Peter 2:22).