What is Reason?

When we speak about reason, we mean uses of the human mind to seek and to understand the truth. We can use our reason in academic disciplines such as psychology, mathematics, and history. Reason is also exercised in producing various technologies and in living life wisely.

Two uses of human reason are especially important when considering the relationship between faith and reason. One is found in science, in which people use the method of empirical verification to determine whether or not some hypothesis is true. Another is found in philosophy, in which people seek wisdom by defining terms, assessing the truth of propositions, and making arguments to establish conclusions.

Some people think that the Church opposes reason, at least as used in science and philosophy. But when we look at what the Church teaches about both science and philosophy, we discover that just the opposite is true. The Church does not oppose science,i but for centuries has supported it. Every Catholic university in the world has departments of science. The Pontifical Academy of Science supports scientific research and gatherings of scientists each year within the walls of the Vatican. The Church proclaimed St. Albert the Great—a medieval pioneer of natural science—the patron saint of scientists.

And Catholics have contributed some of the most significant scientific discoveries of all time. For example, a Catholic priest named Georges Lemaître is known as the father of the Big Bang theory because, using equations from Albert Einstein, he convinced the scientific world that the entire universe (all space, all time, and all matter) arose from a single point. Catholic Alexander Flemming invented penicillin. Gregor Mendel, an Augustinian priest, founded modern genetics. Another Catholic, Louis Pasteur, founded microbiology and created the first vaccine for rabies and anthrax. Nicolas Copernicus, another Catholic cleric, first proposed that the earth revolved around the sun. The list is long of Catholics, indeed many priests and especially Jesuits, who contributed to the development of science.

And what about philosophy? When some people think of philosophy, they think of a college course, the content of which may be pretty remote from the concerns of everyday life. But philosophy is for everyone, and one of the great gifts Pope St. John Paul II left the Church was a reminder of that. We may not be aware of it, but as reasoning human beings we engage in philosophy every day. For example, each of us has some standard by which we judge whether a statement is true or false—this is epistemology. Each of us has some standard by which we judge whether an action is right or wrong—this is moral philosophy. Each of us has some view about what really exists in reality—this is philosophy of nature and metaphysics.

Every human being is, in some sense, a philosopher. In his great encyclical on faith and reason, Pope St. John Paul II noted that everyone explicitly or implicitly asks,

Who am I? Where did I come from and where am I going? Why is there evil? What is there after this life? . . . They are questions that have their common source in the quest for meaning that has always compelled the human heart. In fact, the answer given to these questions decides the direction that people seek to give to their lives (Fides et Ratio 1).

Does the Church oppose reason as it is used in philosophy? On the contrary, John Paul II, who was himself a professor of philosophy, continued, “The Church cannot but set great value upon reason’s drive to attain goals that render people’s lives ever more worthy. It sees in philosophy the way to come to know fundamental truths about human life. At the same time, the Church considers philosophy an indispensable help for a deeper understanding of faith and for communicating the truth of the gospel to those who do not yet know it” (Fides et Ratio 5).

For this reason, the Church has produced some of the most important philosophers of all time, including St. Augustine, St. Thomas Aquinas, and Descartes. In our own time, Catholic professors teach at some of the most prestigious universities in the world. Catholic universities require all their students to study philosophy. The Church does not oppose the use of reason in science or in philosophy or in any other realm, but rather encourages and celebrates it.