Excerpt from 21 Lessons for the 21st Century by Yuval Harari:

In premodern times religions were responsible for solving a wide range of technical problems in mundane areas such as agriculture. Divine calendars determined when to plant and when to harvest, while temple rituals secured rainfall and protected against pests. When an agricultural crisis loomed due to drought or a plague of locusts, farmers turned to the priests to intercede with the gods. Medicine too fell within the religious domain. Almost every prophet, guru, and shaman doubled as a healer. Jesus, for example, spent much of his time healing the sick, helping the blind to see, granting speech to the mute, and making the mad sane. Whether you lived in ancient Egypt or in medieval Europe, if you were ill you were likely to go to the witch doctor rather than to the doctor, and to make a pilgrimage to a renowned temple rather than to a hospital.

In recent times biologists and surgeons have taken over from priests and miracle workers. If Egypt is now struck by a plague of locusts, Egyptians may well ask Allah for help–why not?–but they will not forget to call upon chemists, entomologists, and geneticists to develop stronger pesticides and insect-resistant wheat strains. If the child of a devout Hindu suffers from a severe case of measles, the father will say a prayer to Dhanvantari and offer flowers and sweets at the local temple–but only after he has rushed the toddler to the nearest hospital and entrusted him to the care of the doctors there. Even mental illness–the last bastion of religious healers–is gradually passing into the hands of scientists, as neurology replace demonology and Prozac supplants exorcism.

The victory of science has been so complete that our very idea of religion has changed. We no longer associate religion with farming and medicine. Even many zealots now suffer from collective amnesia and prefer to forget that traditional religions ever laid claim to those domains. “So what if we turn to engineers and doctors?” say the zealots. “That proves nothing. What has religion got to do with agriculture or medicine in the first place?”

Traditional religions have lost so much turf because, frankly, they just weren’t very good at farming or healthcare. The true expertise of priests and gurus has never really been rainmaking, healing, prophecy, or magic. Rather, it has always been interpretation. A priest is not somebody who knows how to perform the rain dance and end the drought. A priest is somebody who knows how to justify why the rain dance failed, and why we must keep believing in our god even though he seems deaf to all our prayers.

Yet it is precisely their genius for interpretation that puts religious leaders at a disadvantage when they compete against scientists. Scientists too know how to cut corners and twist the evidence, but in the end, the mark of science is the willingness to admit failure and try a different tack. That’s why scientists gradually learn how to grow better crops and make better medicines, whereas priests and gurus learned only how to make better excuses. Over the centuries, even the true believers have noticed the difference, which is why religious authority has been dwindling in more and more technical fields. This is also why the entire world has increasingly become a single civilization. When things really work, everybody adopts them.