The book by Ian Morris "Foragers, Farmers and Fossil Fuels" develops a theory about the correlation between technologies of energy capture and cultural values in the very long history of humans. Foragers (hunter gatherers) were egalitarian because they could not afford to accumulate assets and they were prone to violence. Farmers were hierarchical because they needed asset accumulation and specialization to succeed in the technologies of energy capture, and they were less prone to violence. The creation of wealth in the last two centuries would not be the result of capitalism (although it performs well with the contemporary technology of energy capture) but to fossil fuels, which call for political equality, an optimal degree of economic inequality, and a low level of violence. The theory is openly reductionist, functionalist and materialist. But its presentation has the virtue of trying to approach social sciences to other sciences in scope and methodology. I have sympathy with the author's view that human history is a sub-field of biology, and that social science is just a natural science specializing in one particular animal species. Then human preferences are endogenous and subject to scientific explanation, and the fact that humans are more able than other animals to culturally create new things makes the challenge just more interesting. In a small part of the book, the author adds to the debate of why the industrial revolution only took place in Britain. He agrees with those that see relative prices as incentives to invest in technologies (steam power) that could have been developed since ancient Egypt, but adds two interesting ideas: that maritime technologies had created an immense market for ideas in the Atlantic, and that as opposed to foraging and farming (which developed in parallel in several unconnected regions), the industrial revolution could be very fast to spread (due to the technologies of the time), so that it did not give time to anyone else to do the same in a disconnected way. The book format is such that after the author presenting his theses, four "discussants" write lengthy commentaries, to which the author responds at the end. With this, the reader can see different perspectives and put the ideas in context. Although some of the discussion mentions the lack of socially reformist tension in the ideas of the author, both in the discussion and in the main text one misses an analysis of the struggle for values between social classes or groups. The book finishes with a fascinating speculation about how values can evolve in a world of climate change, computer replication of human brains (individual brains and combinations of them) and genetically designed new species: a world of post-humans.