A close family member once offered his opinion that I exhibit the phone manners of a goat, then promptly withdrew the charge - out of fairness to goats.

The mind and the body are inextricably entwined, and rarely are their inseparability clearer than when we're under some kind of mental pressure. The moment we start trying to learn a new skill, make a decision or otherwise think on our feet, our nervous system reacts - with accelerated pulse rate, increased respiration, even sweating.

The families of many athletes - incensed at the sports leagues and hoping to make games safer overall - are increasingly making the brains of players who die prematurely and suspiciously available for study. Some athletes are even making the bequest themselves.

Certainly, people can get along without siblings. Single children do, and there are people who have irreparably estranged relationships with their siblings who live full and satisfying lives, but to have siblings and not make the most of that resource is squandering one of the greatest interpersonal resources you'll ever have.

Scarily, football helmets, which do a fine job of protecting against scalp laceration and skull fracture, do little to prevent concussions and may even exacerbate them, since even as the brain is rattling around inside the skull, the head is rattling around inside the helmet.

A jellyfish is little more than a pulsating bell, a tassel of trailing tentacles and a single digestive opening through which it both eats and excretes - as regrettable an example of economy of design as ever was.

The truth, of course, is that the only necessary and sufficient condition for human beings to murder one another is the simple fact of being human.