And because competencies are unmeasurable, it is impossible to prove or disprove the assertion that everyone who excels in a particular job possesses a particular set of competencies. It is equally impossible to show that people who acquired the competencies they lacked outperformed those who did not—that, in other words, well-rounded people are better. These two statements together are the foundation for most of what companies do to develop the talents of their people, yet each of them is unfalsifiable—you will find no academic papers in any peer-reviewed journal proving the necessity of possessing certain competencies, and no proof that acquiring the ones you lack nets you any increase in performance. Both of these assertions, despite the good intentions that created them, are conjured from thin air—and we can never know if they are correct.

Growth, it turns out, is actually a question not of figuring out how to gain ability where we lack it but of figuring out how to increase impact where we already have ability. And because our abilities are diverse, when you look at a great performance you see not diversity minimized but rather diversity magnified; not sameness but uniqueness.

... the truth is that large success is the aggregation of small successes, and that therefore improvement consists of finding out, in each trial, what works, seizing hold of it, and figuring out how to make more of it. Failure by itself doesn’t teach us anything about success, just as our deficits by themselves don’t teach us anything about our strengths. And the moment we begin to get better is the moment when something actually works, not when it doesn’t.

Of course, if we were able to watch a great athlete training, or a great writer writing, or a great coder coding, we would see that honing a strength is hard work—it is by no means easy to find that incremental margin of performance when you are already operating at a high level—and that a strength is not where we are most “finished” but in fact where we are most productively challenged. Yet we are told to resist the temptation to “just” play to our strengths, and instead to work constantly on our weaknesses. In common parlance, we are told to avoid “running around our backhand.” This betrays, perhaps, a misunderstanding of what a strength actually is. It is not, for each of us, where performance is easiest—it is where performance is most impactful and increasing.

To put its wisdom simply, one could say the fundamental human challenge is this:

It’s hard to learn if you already know.

Unfortunately, we are hardwired to feel as if we know—as if we see reality itself rather than a version of reality filtered through our biases, backgrounds, or expertise. But we can unlearn the habit of knowing and reinvigorate our curiosity.