The double helix of DNA, which forms the basis of genes, is shown in an illustration. Intelligent life reaches maturity when it understands the cause of its own existence. If advanced beings from elsewhere visited Earth, their initial query to judge our progress would be whether we have grasped evolution. Organisms lived on the planet for more than three billion years without this knowledge until Charles Darwin revealed it. Earlier thinkers had partial insights, yet Darwin assembled the first consistent explanation for our presence. His work allows a rational response to a child’s question about purpose. We need not rely on myths for issues such as the meaning of life or human nature. Zoologist G. G. Simpson noted that answers before 1859 hold no value and should be disregarded. Evolution theory now faces little serious challenge, comparable to the acceptance that Earth orbits the sun, though its deeper effects remain underappreciated. Zoology attracts few students, and even they often overlook its philosophical weight. Humanities subjects continue as if Darwin had not existed, though this may shift eventually. The present work does not promote Darwinism broadly but considers its bearing on selfishness and altruism. Beyond scholarly value, the topic affects daily relations, including cooperation, conflict, and sharing. Earlier books on similar themes erred by assuming evolution favors the group or species rather than the gene or individual. The phrase nature red in tooth and claw fits current views of selection. The argument here holds that humans and other animals are vehicles built by genes that have persisted through intense rivalry, implying genes are predominantly selfish. This often produces selfish actions, though limited altruism can sometimes serve gene interests better. The book describes how evolution occurred, not how people should act morally.
