What is Good for the Many is Not Necessarily Good for the Few

If something is good for an individual, it’s good for everyone. I think most people would agree with this statement. But I don’t think it’s true.

The specific case I’m thinking about is agriculture. Having a steady source of calories is good for the population. More people will survive. However, the proportion of ideal outcomes is lower. You will see fewer people of extreme physical fitness. While a hunter-gatherer lifestyle has more volatility. It’s harder to survive the lean times, but in good times, the individuals are stronger.

Life is non-ergodic which is why agricultural societies have dominated the world. But even though hunter-gatherers have been outcompeted, it doesn’t mean that they are not useful.

Evolution is survival of the fittest. Fitness can be along several axes. One axis could dominate outcomes but if you subset off that axis, other attributes matter.

Attributes that are beneficial for the larger population as a whole are not necessarily beneficial for the individual.

Another way of thinking about this is a probability distribution.

Suppose x-axis is “quality” of a person, the green line is the cutoff for survival, the blue line is the probability for farmers and the red line is the probability for hunter-gatherers. The farmers have similar levels of quality and the hunter-gatherers are widely dispersed. But almost all farmers will survive while a significant portion of hunter-gatherers will die even though there are more “high quality” hunter-gatherers. As time goes on, the difference will compound and if group survival is based on population, the farmers will outcompete the hunter-gatherers even though hunter-gatherers are more capable.

An explanation of ergodicity.