Natural revelation refers to God’s self-disclosure in creation, through the things that have been made. Scripture and magisterial teaching are equally clear and emphatic that the knowledge of the existence of God and his basic attributes can be achieved by human reason reflecting on the created order:
- The heavens are telling the glory of God; and the firmament proclaims his handiwork.
- Day to day pours forth speech, and night to night declares knowledge.
- There is no speech, nor are there words; their voice is not heard; 4 yet their voice goes out through all the earth, and their words to the end of the world. (Psalm 19)
It is a common misconception in contemporary culture, even within the Church, that recognition of the existence of God is always a matter of faith. Strictly speaking, however, it does not require faith to recognize the existence of God. For those who reason properly, God’s existence is a matter of knowledge. One can know that God exists by deduction from evidence and principles observable in nature. Many thinkers from classical to modern times have affirmed the existence of God as a matter of reason (Plato, Aristotle, Jean-Jacques Rosseau, Thomas Jefferson, Benjamin Franklin, etc.) The most celebrated recent example is that of Anthony Flew, the most renowned atheist philosopher of the second half of the twentieth century, who finally acknowledged the existence of God near the end of his life, after coming to the conclusion that extraordinary organized complexity of even the simplest living creatures could not be accounted for without positing a creative Intelligence. Those, like Flew, who recognize the existence of God solely as a matter of reason, but reject supernatural revelation, are termed Deists.
St. Thomas Aquinas’ provided a classic summary of typical deductive paths that lead one to the conclusion that God exists in his so-called “Five Ways” (Summa 1:1, Q2 A3): arguments for God’s existence based on (1) motion, (2) causality, (3) contingency, (4) degrees of perfection, and (5) design, respectively. The first three “ways” are forms of the cosmological argument: that the cosmos requires a First Cause, which is God. The fifth “way” is commonly called the teleological argument: that design in nature requires a Designer. St. Thomas’ “Five Ways” are not, and were not intended to be, an exhaustive list of arguments for God’s existence. Other well-known arguments include the moral argument (the reality of moral law seems to require the existence of a Lawgiver) and the ontological argument of St. Anselm (it seems logically necessary that a perfect Being exists).
While it is commonly asserted that the arguments for God’s existence have been defeated by modern philosophy or science, in point of fact, developments in modern natural sciences have lent force and cogency to certain arguments, particularly the cosmological and teleological arguments.
The cosmological argument states that the cosmos requires a First Cause. Its simplest form is called the kalam argument:
Everything that begins to exist, has a cause other than itself.
The universe began to exist.
Therefore, the universe has a cause outside itself.
The cosmological argument had little force in public discourse prior to the 1950s, because it was widely held by scientists that the universe had always existed, and therefore required no cause outside itself. All this changed when the astronomer Edwin Hubble began to publish his observations of the expansion of the universe, which ultimately led to “Big Bang” cosmology: the currently-reigning consensus that the universe burst into existence at a distinct point in time and has been expanding ever since. Interestingly, the renown astronomer Robert Jastrow, himself an agnostic, has documented the fact that Hubble’s now-regnant “Big Bang” model was strongly resisted by the scientific community for decades because of its theological implications: secular scientists themselves recognized that it radically strengthened the cogency of the cosmological argument.
Likewise the teleological argument has benefited from advances in the natural sciences. In the nineteenth century, is was possible to think of microscopic life as simple “blobs of protoplasm” generated spontaneously by natural forces. Advances in microbiology, however, have shown that no life is simple. The simplest known single-celled creature has a DNA with 482 genes comprising 580,000 amino acid base pairs; the simplest theoretical living thing would still require a DNA with 250 genes with around 300,000 base pairs: mathematically, there is essentially no possibility (much less than 1 in 1010) an organism of such organized complexity would arise by natural, material processes alone even given the long age of the earth now generally postulated by geologists. This inability to account for the origin of life without the activity of an Intelligence ultimately persuaded Anthony Flew of a creator God.
A different form of the teleological argument is based on cosmological fine-tuning: the striking fact that the cosmological constants—that is, the numerical values of fundamental natural forces like gravity, the speed of light, and electromagnetism—are all carefully balanced against one another in such a way as to permit a universe in which intelligent life is possible. There are around forty of these natural constants, and typically each one requires the value that it does indeed have to an exactitude of thirty or more decimal points (1 in 1030 or more), otherwise the universe would be inhospitable to human life. Even atheist cosmologists like Stephen Hawking and Sir Fred Hoyle have admitted that this unexpected and extraordinary discovery of extreme balance in the mathematical description of the universe constitutes an argument for God’s existence, even if they do not personally accept it. Stephen Hawking points out: ““If the rate of expansion of the universe one second after the Big Bang had been smaller by even one part in a hundred thousand million million, the universe would have already recollapsed before it reached it’s present size,” making human life impossible. Hoyle remarks: “A commonsense interpretation of the facts suggests that a super-intellect has monkeyed with the laws of physics.” The current popularity of the multiverse theory—the idea that there are an infinite number of universes, thus it is unremarkable that at least one (ours) is finely tuned for life—is not attributable to any scientific evidence, but solely and directly to a religious motivation: to avoid the theistic implications of fine-tuning.
Anyone preparing to teach Scripture on behalf of the Church in some capacity ought to familiarize themselves with the classic arguments for God’s existence as well as the form the arguments generally take today in public discourse in light of advances in natural science. Teachers of Sacred Scripture should be acquainted with these arguments thoroughly enough that they themselves feel their cogency, and are able to explain them in turn to others, because the cultural environment is such today that many students and lay people either believe that the very concept of God is irrational, or else have doubts on that issue. It is impossible effectively to teach Scripture to individuals who have serious reservations about facts that the Scriptures assume, such as the existence of God and his power to act within the natural world. Establishing the reasonableness of these premises goes a long way to enabling the student to embrace supernatural revelation.