Medicine & Health

Epidemiology: Everything Turns on One Number Crossing One

If each case produces more than one further case, an outbreak grows; below one, it fades. That threshold is simple — and almost everything else about the subject is context-dependent.

Longevity and Health: The Big Effects Are the Ones Nobody Sells

The interventions with the largest effects have been known for decades and are unglamorous. Attention flows almost inversely to effect size, for a simple reason — the big ones cannot be sold.

Neuroscience: The Brain Rearranges Itself Around What You Do

The computer analogy breaks down at the most important point — the hardware physically changes with use. That single property explains most of what is practically known about learning.

The Right Amount of Stress Makes Systems Stronger. The Wrong Amount Breaks Them.

Nearly everything that strengthens a system — a muscle, an immune system, an organization — does so by first damaging it slightly.