Buffett's principle: know the boundary of what thou understandest. Invest only within it. The size of the circle matters less than the honesty of its perimeter.
Most catastrophic losses occur when Brothers operate outside their circle without knowing they have crossed the line. The dentist who buys a restaurant. The engineer who shorts options. The doctor who picks crypto.
Expand the circle deliberately, one adjacent domain at a time. But never bet outside it on size.
The Seal of the Chamber
Know the edge of thy knowing. Bet within. Study without.