Training has almost as many fads as a Paris fashion show and they often survive on little more than their followers' enthusiasm.
But there is plenty of hard evidence about the most effective ways for adults to learn. It's objective evidence from thorough research and useful for anyone who teaches, coaches or mentors adults.
Call it blind faith if you like, but the rewards of believing that people are on their way to being first-class are enormous and backed by the research.
Since an influential study in American classrooms in the 1960s established the power of the self-fulfilling prophesy, there have been hundreds more. Our belief in their potential or ability can be a useful motivator for children and adults.