The greatest fool is he who thinks he is not one and all others are. To be wise it is not enough to seem wise, least of all to oneself... Though all the world is full of fools, there is none that thinks himself one, or even suspects the fact.
Baltasar Gracián, 1647 (tr. Joseph Jacobs, 1892)
The trap is universal and invisible from inside: everyone privately believes they are among the sensible ones and the folly belongs to others. That belief is itself the clearest symptom, because a person who cannot imagine being wrong has removed the one check that catches error. The wise operate the opposite way. They hold their own judgment under suspicion, ask what they might be missing, and treat certainty about their own rightness as a warning rather than a comfort. This is not low self-esteem; it is calibration. The person who suspects he could be the fool in the room is the one actually equipped to avoid it, because he is still looking.
Practice
- Treat your own certainty as a flag to check, not a signal to proceed; the position you cannot imagine being wrong about is the one to examine first.
- Ask regularly what the smartest critic of your view would say, and answer it honestly before you commit (maxim 176 keeps the counsel bench).
- Notice when you are cataloguing everyone else's folly; that running commentary is usually the sound of your own blind spot.
Use this when
- Use this before decisions where confidence is high and stakes are real; high certainty plus high stakes is exactly where a missed check costs most.
- Use it as a standing humility, the working assumption that keeps judgment sharp rather than complacent.
Ignore this when
- Don't let self-suspicion curdle into paralysis; the goal is a check before acting, not a refusal to act (maxim 72 still decides).
- Don't perform false modesty; this is a private discipline of honest doubt, not a public display of humility.
A picture of it
Within minutes a doctor settles on the obvious diagnosis, certain enough that she never revisits it. Days pass with the patient not improving, and it is the certainty itself that keeps the real condition hidden behind the plausible one. Only when a colleague's offhand question, what if the first read is wrong, cracks the certainty does she reopen the case, order the test she had skipped, and catch the actual illness in time. Her knowledge never changed. What changed was treating her own certainty as a thing to check rather than an arrival, and the outcome turned entirely on that one reopening.
Certainty that you are not the fool is the fool's one reliable trait. Keep suspecting, and you keep looking.