If you ever find yourself in need of motivation and turn to positive psychology, self-help books, or the social media account of your nearest personal trainer, I’m certain if you look for more than a few minutes, you’ll come across some version of the sentiment, “Whether you believe you can, or cannot, you’re right.”

The one-liner taps into what psychologists call ‘self-efficacy’ – yet another holy grail on the endless quest to helping people change their behaviours for the better. The basic idea is that people who believe they are capable of making meaningful change are significantly more likely to do so. Your self-belief is a self-fulfilling prophecy; and so is your self-doubt.

This provides a very different take on the claim that ideas can change the world. It suggests,