Have science and religion always been at war?

No. The idea that they have always been at war is itself a 19th-century argument, called the conflict thesis, and historians of science now consider it long discredited. Before the 1800s, nobody had even pitted 'science' against 'religion' in writing, partly because the word 'scientist' itself didn't exist until 1834. The conflict thesis came from two writers: John William Draper, whose 1874 History of the Conflict Between Religion and Science argued science was a battle between the 'expansive force of human intellect' and the 'compression' of traditional faith, and Andrew Dickson White, whose 1874 and 1896 books declared that religious interference with science had 'invariably' led to disaster, and free scientific inquiry had 'invariably' benefited religion in return.

One detail shows how unreliable these books were: the popular belief that people before Columbus thought the Earth was flat. In reality, Greek scholars had established the Earth was round by the 5th century BC and measured its circumference by the 3rd century BC, and learned Western culture never forgot it. It was Draper and White who get most of the blame for spreading the flat-earth myth anyway, as part of their case that religion had always held science back. As early as 1908, historian James Walsh called the supposed centuries of Church opposition to science 'founded entirely on mistaken notions', largely driven by exaggerating the Galileo affair. Historian Lawrence Principe has gone further, describing Draper's book as full of facts 'confected' to fit his argument and quotations taken wildly out of context.

Even White didn't mean to claim total, constant enmity between science and Christianity. He wrote plainly that 'religion has done much' for science and had often fostered it; his target was what he saw as restrictive, dogmatic forms of Christianity, a position he said he reached after the difficulties of helping Ezra Cornell found a university without any official religious affiliation.

Today, historians favor what's called a 'complexity thesis' instead. Studies show that most scientists, and most of the public, don't actually see religion and science as being in conflict. Even the two most famous flashpoints, the Galileo affair and the 1925 Scopes trial, were not pure clashes between science and religion: personal and political factors shaped both.