Fisher's Fundamental Theorem

A theorem from biology, translated into kitchen language: a population improves only as fast as its differences allow. No variation, no progress. The rate of improvement depends on the stock of differences available to be selected.

Nature keeps variety not out of sentiment but out of necessity. The identical herd is efficient this year and extinct the year the weather changes. The varied herd looks wasteful — until the drought, when the odd members carry the whole species through.

The theorem has a passport far beyond biology. A company of clones optimizes brilliantly for today and dies on the first disruption. A mind with one method, a portfolio with one asset, a city with one industry — each has traded resilience for efficiency.

So keep odd things alive in your plans: the unfashionable skill, the strange friend, the experiment with no immediate use. Variation looks like waste in stable times. It is actually insurance — and the premium is small compared to extinction.