Christianity and Science

The second question Thomas Aquinas poses to himself in his massive Summa Theologica is “whether sacred doctrine is a science.” Much to the surprise of modern ears, Aquinas—one of the greatest theologians of all time—answers in the affirmative saying, “sacred doctrine is a science.” In a time where we assume science and religion are mutually exclusive, even contradictory, fields, the doctor of the Church argued that Christianity is indeed a science.[1]

Further adding to the difference is the classical view of Christianity. Until fairly recently, universities referred to Christian theology as the “queen of the sciences.” Indeed, of the most highly respected universities in the western world, many were created with the explicit purpose of studying theology and/or training pastors. Though the other sciences were valuable to the founders of Cambridge, Harvard, and Princeton, theology sat atop a throne.

Of course, to the founders of these noble universities, science meant something different than it does to us. To them, science conveyed the sense of the Latin scientia, which means a defined body of knowledge. Thus, when Aquinas argues that Christian theology is a science, his argument revolves around the fact that Christian theology has foundational principles revealed by God. To us, the word “science” is shorthand for the more cumbersome phrase, “natural science.”

Differences in terminology notwithstanding, Aquinas felt the need to defend Christianity’s status as a scientia, and modern Christians feel the need to explain that Christianity is not opposed to the natural sciences. For, many of our contemporaries presuppose that Christianity and the natural sciences are antithetical, that they are diametrically opposed, and that they are in a state of constant acrimony if not outright war.

The presupposition that science and Christianity are contradictory is false, however. Instead, Christianity and science go together quite well; indeed, science cannot exist without Christianity. Science detached from Christian theism is like a fish detached from water: It may gasp for breath for a while as it vainly flops about, but its life is fading fast.

Science Needs Philosophy

The natural sciences make several philosophical assumptions which they cannot verify in themselves. First, science assumes that the natural world has an objective status. Second, science assumes that our sensory inputs—our sight, taste, touch, hearing, and smell—are accurate guides to truth. Third—and most importantly for my purposes—science assumes the validity of our noetic equipment as a guide to truth. That means that science assumes that our reasoning skills really do lead to and discover objective truth. Finally, science assumes that there are objective occurrences of cause and effect within nature that can be tested, quantified, and repeated.

Every one of these is a philosophical position that scientists cannot prove as scientists. To prove these, the scientist must take off her scientist’s goggles and put on a philosopher’s cap. The natural sciences simply have no way to verify that the world is real. They can only perform tests on the world that they see; to say that the world they’re testing is objectively real is different from testing the world entirely.

Science tells me, for example, that two hydrogen atoms combine with an oxygen atom to make water; however, science cannot tell me that I am not being stimulated by a despotic god to believe that I am seeing water where no water exists. In this latter case, the water molecule is a hallucination. A philosopher could probably quiet my fear of this despotic god, but science must remain silent on the subject. In other words, science takes what comes to us at face value, assumes it’s real, and then tests it. They only report what they sense and create situations to manipulate what nature does. However, if nature is not objectively real, the scientist’s tests are all done in vain, and they’re only manipulating a hallucination.

Similarly, scientists employ reasoning to do research; however, they cannot back up their reasoning skills. Scientists use modus ponens quite effectively, for example; they know that if two hydrogen atoms come into contact with an oxygen atom under the right conditions, they form a water molecule. Theoretically, they can then put the requisite atoms together and create water. They’ve just followed modus ponens, a basic principle of reasoning.

While scientists can see the results of reasoning, they do not have the tools to explain the logic itself. Instead, as scientists, they must take our reasoning abilities as a fact of the universe and work from there. Our reasoning abilities are thus one of the foundations of science; since it is a foundation of science, science cannot itself prove that reasoning is aimed at truth. Instead, the scientist must look to something else to provide a basis for its ardently held philosophical position that our reasoning abilities are competent guides to truth. In short, science needs philosophy, because science cannot ground the reasoning that forms the critical basis for scientific endeavors.

Philosophy Needs Christianity

Most of us probably assume that our reasoning abilities are accurately aimed towards truth; few of us, like our scientist friends above, have given thought as to why reason works. You may think that our reasoning abilities work because you can see them working. You might think of some biscuits that you’re making for breakfast and follow this line of reasoning: If I put the biscuits in the oven at 350 degrees 20 minutes ago, they are done. I did indeed put the biscuits in the oven at 350 degrees 20 minutes ago. Therefore, they are done, and I should probably get them out of the oven before they burn. If you’ve had any experience like this, you know that reasoning is a wonderful thing and that it works.

But, consider what the world would be like if our reasoning abilities were not aimed towards truth. Whatever that world looks like, one thing seems clear: We wouldn’t be able to reason that our reasoning abilities were leading us to falsehood. Instead, we would trust our logical abilities while being unable to see their manifold errors. Thus, if we are to trust reason, we can’t trust it just because it works; instead, we must look elsewhere.

René Descartes made this argument in his famous work, Meditations on First Philosophy. In this short work, Descartes seeks to find the one thing that he is certain about. Along the way, he considers reasoning; however, he rejects reasoning as the one thing he’s certain about because he says reasoning falls short of certainty. He says that an evil god could make him feel certain of his reasoning abilities and could thus lead him to error. Instead, he opts for existence, thus his famous line, “I think; therefore, I am.”[2]

Descartes’s argument to the side, he made the same point I am making: Reasoning in itself is an insufficient ground for reason. Thus, as we’re looking for a basis for logic, philosophy seems unable to ground reasoning. For, if our reasoning abilities are themselves an insecure foundation, then all the ramblings of the philosophers are just that: ramblings.

Christianity as the Basis of Reason

Fortunately, Christianity provides just the foundation required for the reasoning that scientists so adroitly employ. As Descartes would later realize, the Christian God provides a stable foundation for logic. Christianity testifies that reason works because God is reasonable. Since God is a logical being, he put logic into his good creation. As Paul said, “God is not a God of disorder.”[3] Thus, our reasoning abilities reflect God’s character and personality. We can trust that our reasoning abilities are aimed at objective truth about the world because they have a foundation in the character of our logical God.


Christianity and the natural sciences are good partners. Whether we realize it or not, science stands atop numerous philosophical positions. Each one of these positions stand outside of the purview of science. Working only with the tools of science, scientists cannot either confirm or deny their philosophical presuppositions; instead, they can only work out the cause and effect nature of the universe in which we live. To ground these presuppositions, such as the presupposition that our reasoning abilities are accurate guides to truth, science needs philosophy.

Naturalistic philosophies find it difficult to ground logic, however. Logic appears to be a brute fact about the universe; but, were it not aimed at truth, we wouldn’t be able to reason that our reasoning abilities are faulty. When we attempt to find a better foundation than brute fact, the Christian understanding of God is there to assist us. For, in Christianity, we have the much-needed ground for our logic. In grounding our logic, Christianity grounds all extensions of logic, including the natural sciences.

Notes & Sources

[1] Thomas Aquinas, Summa Theologica, trans. Fathers of the English Dominican Priests (Notre Dame, IN: Ave Maria Press, 1981), Q. 1, Art. 2.

[2] René Descartes, Meditations on First Philosophy, (Cambridge, UK: Cambridge University Press, 1996).

[3] 1 Corinthians 14:33, NIV.

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