It is a commonplace belief that there is a war between science and religion. From the standpoint of science, the anthropologist Leslie White has argued that as science gains knowledge in one sphere after another, religion is forced to retreat. Thus, for instance, the rise of psychology has meant the decline of religious explanations of mental functioning, such as possession. The current Roman Catholic training and placements of exorcists thus becomes something of a sideshow.

From the viewpoint of religion, science is sometimes seen as an elucidation of God’s handiwork. While my point of view is clearly secular, the point of this article is to show how a secular point of view derives from Christian history and belief. I will identify a scientific worldview with secular humanism.

Let’s start with an observation made by Paul Tillich, a theologian who is part of what has been called the neo-Orthodox camp. He argues that the basic Christian worldview is more amenable to scientific development than that of a karmic worldview typical of some Eastern religions. In karmic perspective, history is circular: birth, death, rebirth. In Christianity there is a linear perspective, from a beginning at Creation to an end at the Final Judgment. Hence, Christianity promotes a frame of mind that is favorable to the idea of progress. Karmic thought is less friendly to the idea of progress because for it, history is just more of the same, over and over.

That is secular humanism’s debt to Christianity in its most general terms. There are more specific contributions. Let’s start with the thirteenth century.

In those years, the Catholic Church produced several major philosophers. Two are of particular interest for us here. One was Thomas Aquinas; the other was Roger Bacon. While Aquinas is by far the more famous, Bacon is more important for the development of science and hence of a secular worldview.

Aquinas adopted an Aristotelian philosophy, in which there are four causes for anything: a material cause, a formal cause, an efficient cause, and a final cause. The material cause is the thing from which something is formed. Gold is the material cause of a gold ring. The formal cause is the shape of the ring, that which the gold is to become. The efficient cause is the making of the ring. Then there is a final cause. Here I will use a different example. The final cause of teeth is to bite and chew. The final cause is teleological. Thomistic reasoning is highly deductive, and its value from a scientific perspective is both limited and limiting. The teleological orientation of the final cause leads to a priori—that is, before the fact—reasoning. Evidence does not have much bearing.

Roger Bacon, an English Franciscan monk, was different. He was in his time the foremost advocate of experimental science. Rather than relying simply on deductive reasoning, he was prepared to make the inductive leap. He also was a keen supporter of what has been called the language of science: mathematics. “Mathematics is the gate and key of the sciences,” he declared. This is not to say that he was the epitome of the scientist: in addition to being a Catholic monk, he was also a firm believer in astrology.

The paradox of the man of science drawn to astrology reminds me of the court case in Dover, Pennsylvania, where the court threw out the teaching of intelligent design theory in public schools. One of the witnesses opposing intelligent design was a Catholic biologist. Under cross-examination, he was asked how as a Catholic he could dismiss intelligent design. “Not everything a scientist believes is science,” he replied. As he was a responsible scientist, his Catholicism was not relevant to the issue of intelligent design.

Roger Bacon was a precursor of another Bacon: Francis—another Englishman who lived in the late sixteenth and early seventeenth centuries. He also stressed inductive reasoning. If I drop a rock, it will fall to the ground. I know this because the rock has acted this way on any number of other occasions, always falling to the ground. I make the inductive leap.

Four centuries after Aquinas and Roger Bacon, at the time of Francis Bacon and Galileo, Aquinas’s philosophy continued to hold sway. Things are necessarily the way they are based on the final causes that make them so, according to Thomistic thought. When Galileo found that, contrary to the Thomistic view, the moon was not smooth, Thomists replied that the telescope he had built lied. When he invited a distinguished churchman to look through his telescope to see the moons of Jupiter, the churchman declined, arguing that the nature of the heavens as explained by philosophical knowledge proved that there are no moons of Jupiter. Not seeing is believing.

But another “really big something” happened in the sixteenth century. Martin Luther kicked over the traces. Luther was a biblical literalist, hence apparently a poor candidate to be a promoter of progressive social and scientific thought. Erasmus, his philosophical opponent, was a far nicer guy. As a Catholic, Erasmus was not a biblical literalist because the Catholic Church believed and still believes that doctrine consists not only of the Bible but also of the traditions and interpretations of the Church. Gentle Erasmus argued for free will, saying that men can act—with God’s help. In a rather nasty attack on Erasmus titled “The Slavery of the Will,” Luther replied that logically, God did not need man to act. God can do it all himself, but man can’t. Not by acts but by faith alone is man saved.

Luther, as I said, is an unlikely source of scientific and intellectual progress. Yet he is. In opposition to the power of the Catholic Church and the authority of the clergy, he enunciated the principle of the priesthood of all believers. The ramifications of this doctrine were revolutionary. Each believer was to interpret the Bible for himself. Luther seemed to feel that all believers would understand the Bible in the same way: the way he did. Nothing could be further from the truth. Incompatible understandings of the Bible proliferated.

And as biblical study amid diversity of understanding took hold, biblical study itself began to become scientific—the so-called higher criticism. And as higher criticism proceeded, it moved further and further from belief. Everything became fair game for study and exploration. It became clear, for example, that there were several authors of Genesis. Biblical authority could no longer curtail science.

There you have it. The Christian viewpoint, or to use the fancy word Weltanschauung, assumes progress and development. Scientific progress was constrained early on by a Thomistic overemphasis on deductive reasoning and by teleology. However, an opposing emphasis on experiment and inductive reasoning, which was a lesser tendency back in the thirteenth century, eventually gained the upper hand. Then in the sixteenth century, a religious reactionary, Martin Luther—against everything he intended—overturned biblical authority, leaving even the very Bible open to exploration.

Everything was open to question, and the door was opened to secular humanism. Otherwise, our minds would still be constrained by religious orthodoxies.