“Knowledge is knowing that a tomato is a fruit; wisdom is knowing not to put it in a fruit salad.”[*] Or more biblically, “Teach us to number our days, that we may gain a heart of wisdom.”[12] If you’re experiencing decline in fluid intelligence—and if you are my age, you are—it doesn’t mean you are washed up. It means it is time to jump off the fluid intelligence curve and onto the crystallized intelligence curve.
