...grit grows as we figure out our life philosophy, learn to dust ourselves off after rejection and disappointment, and learn to tell the difference between low-level goals that should be abandoned quickly and higher-level goals that demand more tenacity. The maturation story is that we develop the capacity for long-term passion and perseverance as we get older.

Thus ended the first and adventurous part of his existence. What followed was so different that, but for the reality of sorrow which remained with him, this strange part must have resembled a dream.

Follow your passion was not the message I heard growing up. Instead, I was told that the practical realities of surviving in the real world were far more important than any person living a sheltered life such as my own could imagine. I was warned that overly idealistic dreams of finding something I loved could in fact be a breadcrumb trail into poverty and disappointment.

A vivid - if somewhat melodramatic - firsthand description of what deliberate practice can feel like comes from dancer Martha Graham: 'Dancing appears glamorous, easy, delightful. But the path to the paradise of that achievement is not easier than any other. There is fatigue so great that the body cries even in its sleep. There are times of complete frustration. There are daily small deaths.

You think intelligence and grit can succeed by themselves, but I'm telling you that's a pretty illusion.