You have a switch inside you. Your switch toggles from causing your victories (ON) to causing your defeats (OFF). The perfect place to look and determine which state your switch was in, is after the fact, by judging your outcomes. That’s the obvious, infallible and accepted proof, isn’t it?
The problem, of course, is that by then it’s too late to do anything to influence those outcomes toward victory and away from defeat. The trick is to learn to recognize your switch’s condition before the outcomes occur and then flip it to the victory mode ON.