In his book Sapiens, Yuval Noah Harari shares examples of how evolutionary success for an entire species doesn’t always mean positive things for individuals within the species. His conclusion, and the evidence of evolutionary success for humans, livestock animals, and other species, is similar to the Repugnant Conclusion, an idea common in ethical psychology. As a quick summary, the Repugnant Conclusion can be thought of in the following way. Imagine our planet has 10 billion people living, and all 10 billion people would score their happiness at a 7. If you summed up the total happiness of the planet you would get 70 billion. But imagine that our world could support the lives of 100 billion people, but only if each person had a miserable life and rated their happiness level as 1 – just barely worth living rather than not living. If you summed up the total happiness of all 100 billion people, you get 100 billion, an increase of 30 billion in terms of total happiness over the planet with 10 billion fairly happy people.
Hardly any of us would want to live in the planet where there were more living people, but almost all of them were unhappy, with lives they considered only barely worth living. But evolution doesn’t really care about happiness. Evolution seems to just care about whether lives are barely worth living, and whether genes are being passed along. Yuval Noah Harari would argue that throughout history numerous species have successfully evolved through strategies that seem to follow the Repugnant Conclusion.
When we imagine evolution, we tend to think of everything getting better. Humans, plants, and animals evolve to become bigger, faster, stronger, and better able to survive. Surely, we imagine, that means that each individual has a better life and experience than the individuals that came before it. After all, each successive generation, per evolutionary pressure, should be a better fit for survival than its predecessors. Unfortunately, we can evolve in the direction of the Repugnant Conclusion, with fitness for survival having nothing to do with actual individual level fitness and happiness. Greater numbers of individuals may be able to survive if they are all a little less happy, require a little less in terms of resources, and can better manage being crammed into a tight space. Harari writes, “this discrepancy between evolutionary success and individual suffering is perhaps the most important lesson we can draw from the Agricultural Revolution.”
When we think about evolution, Harari argues that, “we have to consider how evolutionary success translates into individual experience.” Today, there are far more chickens alive than at any other point in history. By evolutionary standards, chickens have done great. They continuously pass their genes along and even have another species invested in the continued survival and population growth of chickens. However, individual chickens have miserable lives, often confined to cages they cannot move around in or stand-up in. Their lives are also very short, very congested, and their deaths can be brutal. The individual experience for a chicken is about as bad as it could be, but the species as a whole is booming. Harari argues that similar things have happened in Human Evolution. We might not all be trapped in cages, but we have had changes in our species that have made the individual lives of humans worse while propelling the survival and continued evolutionary success of the species forward. Evolution does not simply mean better. It means continued survival and change in the face of challenges for survival. Sometimes the experiences of the individuals can improve, but that is not always the case.