To provide an answer to the question “Is it self-evident that God exists?” this article examines the following: (a) whether or not the proposition “God exists” is a self-evident proposition, (b) whether or not the existence of God is self-evident through sense-experience, and (c) whether or not the light of faith can be said to provide self-evident knowledge of the existence of God.
a) Self-evident propositions
Several times in his writings, Saint Thomas Aquinas answered the question “Is it self-evident that God exists?” by saying that the proposition “God exists” is “self-evident in itself, but not self-evident with respect to us.” (1)
Here is a clarification of what Aquinas meant by “self-evident propositions.”
Self-evident propositions are propositions that are known as soon as their terms are known. A self-evident proposition emerges when subject and predicate disclose their own intelligibility by themselves, without the need for recourse to the mediating intelligibility of other terms. (2)
For example, Aquinas tells us that the affirmation, “the remainders of equals subtracted from equals are equal,” is self-evident in itself because the terms that enter into the proposition disclose their own intelligibility by themselves. (3) This can be seen as easily as follows:
If you pour exactly 16 milliliters of water into each of two identical glasses and then take exactly 4 milliliters of water away from each glass, you are left with two glasses each containing exactly 12 milliliters of water.
The cognitive sequence is the following: (a) everyone understands what it is to be equal, and (b) everyone understands what it is to be subtracted. Therefore, (c) everyone understands that “if you take equals away from equals, the remainders are equal.”
The convincing force of a self-evident proposition is grasped automatically. A self-evident proposition needs no proof. Its meaning is obvious. And, once the terms are understood, the mind instantly assents to the truth of a self-evident proposition.
Why, then, did Aquinas say that the proposition “God exists” is self-evident in itself, but not self-evident with respect to us? Here is the answer:
Even when a proposition is self-evident in itself, for those who are not able to comprehend the intelligibility of the terms, the truth of the proposition remains unknown, and thus for them, the proposition is not self-evident.
The predicate “exists” belongs indeed to the understanding of the subject “God,” but since the subject “God” is beyond our comprehension, the connection that exists between the subject “God” and the predicate “exists” is not instantly perceived by the human mind.
Our initial contact with the term “God” and our efforts to understand the intelligibility of the term “God” do not result in our understanding automatically the validity and certainty of a connection between the subject “God” and the predicate “exists.” The validity and certainty of this connection have to be derived and established through the mediation of the intelligibility of other terms.
For this reason, we see that throughout the centuries thinkers have used the tools of demonstration and reasoning to come up with arguments for the existence of God.
The truth of the existence of God is a conclusion established through reasoning. The proposition “God exists” is not a self-evident proposition with respect to us.
Relevant to the present discussion is the fact that, in addition to self-evident propositions, there are other realities that are also said to be self-evident. Some sensible qualities are self-evident to our external senses and the existence of the material world around us is self-evident to our intelligence.
Color, for example, is self-evident to sight, the sound is self-evident to hearing, and when you hear and see a person speaking, you simultaneously grasp that that person exists.
Direct sense-knowledge is the strongest evidence that a thing exists. But to grasp the existence of a thing through sense-knowledge there is a restriction, namely, that one has to have direct sense-contact with the existing sensible thing.
Is it self-evident through sense-knowledge that God exists? The answer to this question is a definite no. God is not a physical object accessible to us through the external senses. This article will not discuss at length the issue of why God is not a corporeal being since this would require more space than is available here. Suffice it to say that metaphysical consistency indicates that God is, in essence, a spiritual, immaterial being.
God can indeed be discovered in the movement, order, measure, and beauty of the things of nature, but the things of nature are only an occasion to rise to some knowledge of God as the first cause. God is not the first thing we know, and in no way can one say that in grasping the accidental perfections of the things of nature one is simultaneously grasping the existence of God.
It is instructive to note here that by means of demonstration and reasoning one can also prove the existence of a thing without having to have recourse to the direct sense-experience of an existing exemplifying individual. The existence of kangaroos, for example, is an established fact and one does not have to go to Australia or to a zoo in order to affirm with complete certainty that kangaroos exist.
Similarly, one can reach a point when one can affirm with certainty that the proposition “God exists” is a true proposition but to know this truth one has to go through a good number of mediating steps.
c) The light of faith
Aquinas was well aware also of the fact that not even the extension of the knowledge of God made possible by the fonts of revelation was enough to make the proposition “God exists” a self-evident proposition with respect to us. (4)
The content of the articles of faith is given by God Himself through supernatural revelation. Thus the assent of faith is based on the authority of God who reveals and not on a full understanding of the articles of faith. The assent of faith is ultimately an act commanded by the will.
It is well known that some souls experience God so closely through faith that God’s existence seems to them to be self-evident. But no, the habit of faith elevates the human intellect beyond its natural capacities, but the supernatural truths imparted to the elevated mind are not self-evident to the natural light of reason.
In fact, it is also true that holy souls ordinarily have an initial distrust of their subjective experience of God. This distrust is based on the principle that if the subjective experience is indeed an experience of the divine, God will provide unmistakable confirmation for it. Holy souls know that it is better to distrust themselves and trust God than to be deceived by a fleeting subjective experience.
In the case of Saint Paul, for example, God also used Ananias to provide confirmation of what Saint Paul had experienced in his rapture. (See Acts 9:3-19.) In the case of the Virgin Mary, God also used Elizabeth to provide confirmation of the mystery which was taking place in Mary. (See Lk 1:36-56.) And in the case of Bernadette Soubirous, God used the fountain of water to provide confirmation to Bernadette that the vision was true. (See Office of Readings in the Liturgy of the Hours for February 11.)
The subjective element of the experience of the supernatural does not make the identification of the cause of the experience self-evident. Other intermediary elements are needed to confirm the reasonableness of the attribution of the experience to God.
Having a strong, deeply ingrained habit of faith can certainly make the existence of God clear to the soul perfected by grace, but the experience of the supernatural does not make the existence of God a self-evident truth to the natural light of reason.
To know God’s existence we have to employ the power of reason and go through a good number of mediating steps and intermediary conclusions. It is through demonstration and reasoning that we can affirm with certainty that the proposition “God exists” is true.
(1) See Thomas Aquinas, “Summa Theologiae,” part I, question 2, article 1; “De Veritate,” question 10, article 12; “De Potentia,” question 7, article 2, ad 9; “Summa Contra Gentiles,” book 1, chapter 11, nos. 1-4; and “In I Sententiarum,” distinction 3, article 2.
(2) See Michael V. Dougherty, “Thomas Aquinas on the Manifold Senses of Self-Evidence,” “The Review of Metaphysics” 59 (2006): 601-630; and Joseph M. Christianson, “Aquinas: The Necessity and Some Characteristics of the Habit of First Indemonstrable (Speculative) Principles,” “The New Scholasticism” 62 (1988): 249-296.
(3) See Aquinas, “Commentary on Boethius’ De Hebdomadibus,” lecture 1.
(4) See M. V. Dougherty, “Aquinas on the Self-Evidence of the Articles of Faith,” “The Heythrop Journal” 46 (2005): 167-180.