People often ask, "What is the single most important environmental/population problem facing the world today?" A flip answer would be, "The single mo… - Jared Diamond

Behavior evolves through natural selection, just as anatomy does. Hence if sex is enjoyable, natural selection must have been responsible for that outcome.

If the Easter Islanders couldn't solve their milder local problems in the past, how can the modern world hope to solve its big global problems? People who get depressed at such thoughts often then ask me, “Jared, are you optimistic or pessimistic about the world’s future?” I answer, “I am a cautious optimist.” By that, I mean that, on the one hand, I acknowledge the seriousness of the problems facing us. If we don’t make a determined effort to solve them, and if we don’t succeed at that effort, the world as a whole within the next few decades will face a declining standard of living, or perhaps something worse. That’s the reason why I decided to devote most of my career efforts at this stage of my life to convincing people that our problems have to be taken seriously and won’t go away otherwise. On the other hand, we shall be able to solve our problems – if we choose to do so.

Perhaps we could benefit by selectively adopting some of those traditional practices. Some of us already do so, with demonstrated benefits to our health and happiness. In some respects we moderns are misfits; our bodies and our practices now face conditions different from those under which they evolved, and to which they became adapted. But we should also not go to the opposite extreme of romanticizing the past and longing for simpler times. Many traditional practices are ones that we can consider ourselves blessed to have discarded — such as infanticide, abandoning or killing elderly people, facing periodic risk of starvation, being at heightened risk from environmental dangers and infectious diseases, often seeing one’s children die, and living in constant fear of being attacked. Traditional societies may not only suggest to us some better living practices, but may also help us appreciate some advantages of our own society that we take for granted.