08/06/2016 06:21 BST | Updated 08/06/2017 06:12 BST

Hero of Harlem Beats Ayn Rand With Altruism

Volunteering to help others feels good and improves our health. But if serving others benefits us aren't we just being selfish? Is altruism (doing something for others even if we don't benefit) even possible? Philosopher Thomas Nagel thinks not. To him altruism is unattainable because our motives are always selfish . Nagel's view seems to be supported by evolutionary theory, which states that we are ruled by selfish genes behaving as though they are fighting to grab as much as they can to beat out competitors. Ayn Rand takes the argument further and asserts that altruism is bad because it prevents the fittest genes from 'rising to the top'.

Evolutionary theory would be compatible with altruism if we could expect the same in return. One monkey picks the parasites from the back of his monkey friend, then his monkey friend returns the favor. But it is hard to see how the 'you scratch my back, I'll scratch yours' gene could ever gain dominance in the first place. The first human ancestor to have a 'gene' to scratch his friend's back would not have his own back scratched. He'd be busy scratching backs while his friends were eating, hunting, and making babies. The nice monkey wouldn't have as many offspring, and the first 'altruism gene' would get crowded out by more selfish genes every time it appeared.

In spite of its philosophical opponents and evolutionary implausibility, altruistic acts are quite common. Wolves bring back meat to pack members not present at the kill. Termites self-inflict fatal wounds to release a sticky substance from a specialized gland so that invading ants get stuck. Even humans, who appear to be exclusively brutal on the news, can also be exceptionally altruistic. My favourite altruism story is about how Hero of Harlem (Wesley Autrey) saved a 20-year old film student called Cameron Hollopeter.

At lunchtime on January 2, 2007, Autrey was waiting for a train at the 137th Street subway station in Manhattan. Near them Hollopeter started having a seizure, and fell onto the tracks. Autrey dove onto the tracks to save Hollopeter. Then Autrey saw the lights of an oncoming train approaching; without enough time to drag Hollopeter away, he threw himself over Hollopeter's body and held him down in a drainage trench between the tracks. The train operator slammed on the brakes but it was too late: all but two cars passed over them, close enough to touch Autrey's cap. Luckily they both survived without more than a few scratches.

The best explanation for altruism that saves evolutionary theory comes from Axelrod and Hamilton. They argue that since we share genes with our close relatives, helping our relatives will help our genes survive even if our individual chances of survival are lowered. But this only makes sense if our group's genes evolve as one. Unfortunately for Nagel and Rand, this view makes them wrong. If we (or our genes) are all in this together then altruism is possible and good.

Sometimes the academic debate about altruism doesn't matter: a starving person won't care what your motives are as long as you feed them. However whether our motives are selfish does seem to be important for our health. A sample of over ten thousand Wisconsin high school graduates who were followed from their graduation in 1957 to 2004 were asked:

• Whether they had volunteered in the past 10 years

• How often they volunteered, and how long they volunteered

• The reasons why they volunteered

The reasons they volunteered were then classified as selfish (self-exploration, looking to feel better, or to escape from troubles), or altruistic (feeling compassion, or community service). Those with selfish motives did not seem to have any health benefits from volunteering, whereas those with altruistic motives had greater health benefits from volunteering. The study was not an experiment so it's possible that people who volunteer for altruistic reasons are somehow healthier to begin with (although researchers controlled for this the best they could). However it was a large well-controlled study suggestive of a real effect.

The good news is that you don't need to heroically dive in front of an oncoming train to be altruistic. In fact please don't do that. You simply have to act on feelings of compassion or community service that arise. There is just one catch: don't focus on your personal gain, or your selfish genes might gobble up any health benefits you might otherwise have reaped...