A distinction I read somewhere, that I think is useful, is that people tend to be either primarily conceptualist in their thinking, or they are empiricists who learn from experience. Conceptualists have their big breakthroughs before the age of 35, and empiricists have their big breakthroughs after 35.

In conceptual fields, such as math and physics, the big breakthroughs happen young. Werner Heisenberg was 27 when he came up with the Uncertainty Principle, and Einstein was 26 when he discovered relativity.

In fields where progress is primarily empirical, such as biology, the big breakthroughs tend to happen later. Alexander Fleming was 42 when he discovered penicillin and Jonas Salk was 40 when he invented the vaccine for polio.

This distinction can be extended to artists. To write a great empirical novel, one rich in observed life experience, one must live a long time, and therefore Tolstoy was 41 when he wrote War and Peace. But to write a novel where one demonstrates new techniques for grammar and structure and pacing (a novel noteworthy for conceptual innovation) then one will be young, and therefore Hemmingway was only 26 when he wrote The Sun Also Rises.