To clarify this point, one must consider human cognition concerning God, and as a basis for this consideration one must note certain features of human cognition in general.

One can say both of human persons and of other primates that they see and hear, perceive things as units, remember and dream, learn by experience, tell the helpful from the threatening, love and hate, fear and become enraged, strive after things and enjoy satisfactions. Such experience is common to the higher animals, including rational animals. This form of consciousness is preconceptual and lacks reflective discrimination between subject and object, between self and other.

This level of awareness is called “sentient” to distinguish it from the properly human functions of thinking and willing. These properly human functions and their level of awareness are called “rational,” using the word in a wide sense. Even sentient awareness in human persons is permeated by reason and will, for while the two levels are distinct, they are not separate. They make up a single system of human conscious life.

Human persons are created in God’s image (see Gn 1.26–27). For this reason, men and women are not only valuable; they are beings of dignity, of inherent worth (see Ps 8.5–7). The capacities of intelligence and free choice raise human persons above the rest of material creation and make them like God (see S.t., 1, q. 93, a. 2). These same capacities are the ground of human moral responsibility and of the openness of human existence to share in divine life (see GS 12–17; also S.t., 1–2, q. 5, a. 1).

Human persons know themselves as selves; they know everything else as a world of other persons and of things. The rational capacity to distinguish oneself as a knowing subject from other persons and the objects one knows is exercised in reflective intelligence, by which one knows oneself knowing. In this reflection, one can distinguish what one knows from one’s knowing of it and the conditions of this knowing; in making this distinction one knows the truth of one’s knowing and posits the content known as other: So it is, not merely in my knowing, but in what I know, in reality (see S.t., 1, q. 16, a. 2).¹⁵ Truths known in reflection are propositions, “pro-positions” because we put forth and posit as real what we know to be true. We call a truth a “proposition” precisely insofar as it is known and present in our knowing; the reality attained in propositional knowing is some state of affairs.

Something of the reality which will be known in this objective way must first be understood (see S.t., 1, q. 27, a. 1; q. 34, a. 1; q. 85, a. 2; S.c.g., 4, 11). Understood aspects of a reality are concepts. We call these aspects “concepts” precisely insofar as reality is grasped in our understanding of it. We often construct tentative propositions and then seek to determine whether any state of affairs corresponds to them; to do this is to ask a question. A proposition which picks out a state of affairs which is not real is a false proposition.

Human rational awareness is based upon sentient awareness (see S.t., 1, q. 84). Our first understandings are of aspects of things given in experience; the first truths we know are about the reality of states of affairs in the world of experience. Already in knowing truth we know ourselves with an awareness other than sentient awareness, and so from the start our knowledge of the world of experience points beyond this limited domain. By reasoning we come to know order among things. In investigating the order of things we discover loose ends in things experienced, and seek after causes—factors not yet experienced—to complete the pattern which is grasped rationally as incomplete.¹⁶

Sometimes it is said that human persons have some direct and preconceptual awareness of the world and even of God—a sort of direct look at or undifferentiated contact with reality. It is true that sentient awareness is preconceptual and undifferentiated. Also, very basic truths are known in propositions which are so obvious and familiar that it is hard to express them in language; it is easier to talk about aspects of reality which vary and are differentiated.

However, there is neither evidence nor any teaching of the Church that human persons have any intellectual awareness of anything prior to concepts (see S.t., 1, q. 88). The self-awareness which is incidental to knowing truths about the world of experience is not preconceptual, for it arises from the understanding of experienced things and takes form in the concept of the self who knows, the self one calls “I” (see S.t., 1, q. 87, a. 1). Preconceptual awareness would be without understanding of any aspect of reality and would be awareness of no state of affairs as real. It is unnecessary to posit such awareness. To do so leads to avoidable mystifications.¹⁷

Still, as already indicated, human rational knowledge is not limited to the world of experience and the knowing self, since reason follows the pointing of these beyond themselves: “Ever since the creation of the world his invisible nature, namely, his eternal power and deity, has been clearly perceived in the things that have been made” (Rom 1.20). Vatican I defines: “If anyone says that the one and true God, our creator and lord, cannot be known with certainty with the natural light of human reason by means of the things that have been made: let him be anathema” (DS 3026/1806).

The general form of the reasoning by which one comes to know God from experience is simple enough. In many ways humankind experiences the world as incomplete, as in need, as somehow unsatisfying to the human mind and heart. Part of this unsatisfactoriness no doubt is based upon our awareness that we will die; this fact seems absurd to persons, who have an inherent sense of their own dignity. Another factor is our awareness of solidarity and community with ancestors and descendants; this suggests another dimension of reality, outside worldly time and space, in which we remain with others. Yet another factor is our poignant sense of evil, especially of our own guilt, which cries out for salvation and forgiveness. Shaping all this experience is the realization that the world of things which come to be and pass away needs as a principle of its reality something independent in being.

Nothing within the world of experience nor even the human self grasped in knowing this world is able to remove the absurdity of death, unite the community of humankind, overcome evil, and account for the reality of things not real of themselves. And so an Other, apart from the world of experience but required by it, is posited as an invisible and higher reality. This Other almost inevitably is thought of as a person or as something like a person. Virtually every human group seeks ways to live without tension and in harmony with this quasi-personal Other. The ways diverse peoples find and use constitute their religions. Thus, religion of some sort is almost a universal phenomenon.

The formulation of Vatican I and the common aspects of efforts by Catholic philosophers to articulate reasoning toward the existence of God point to a precise argument which follows the general form of reasoning already described but leads to a very careful way of thinking and talking about God. Elsewhere I have attempted to lay out this precise argument in detail.¹⁸

The reasoning begins from the distinction between understanding propositions and knowing them to be true. Wherever this distinction holds, it implies that the states of affairs picked out by propositions are not real of themselves, but require conditions beyond themselves to be real. An infinite regress (in the series of conditions of conditions of . . . ) is meaningless; some explanation is rationally required for the reality of everything which has borrowed reality. Thus, there must be a principle of reality which is other than any state of affairs having borrowed reality; this principle must have its own reality of itself.

In this reasoning one reaches a principle which really is wholly other than anything we understand. For our understanding proceeds by concepts which grasp aspects of entities which cannot be real of themselves. It follows that whatever we understand about anything else will not be an understanding of the Other whose reality is of itself. The attributes we predicate of everything else must be denied of this principle of reality. It is neither one nor many, neither changing nor unchanging, neither animate nor inanimate, neither bodily nor mental—using these words in the same senses in which they are used to describe entities having borrowed reality. We do not know what the Other is; we know what it is not.¹⁹

Can we even say of this principle that it is “real,” that it is “other?” Not if these words are used in the same sense in which they are used when we talk of familiar entities. As St. John Damascene teaches: “Concerning God, it is impossible for us to say what he is in his essence; it is more fitting, rather, to discuss how he is different from everything else. For he belongs not among things that exist, not because he does not exist, but because he is beyond all existing things, and beyond even existence itself. For if all modes of knowledge are concerned with what exists, that which is beyond knowledge must be beyond existence and likewise, what is beyond existence must be beyond knowledge” (FEF 2340). We can say “God exists” only because in the context of the reasoning by which one reasons beyond existing things, the word “exists” takes on a special meaning, which does apply to that Other on which they depend for their reality.

Even words such as “principle” and “cause” do not express what this Other is in itself, for they cannot be used of it in the sense in which they are said of anything else without eliminating the uniqueness which must belong to the Other. The Other must be unique to fulfill the requirement for which it is posited—to account for the reality of everything else. Rather, in saying that the Other is “principle” or “cause” we are saying that whatever it is in itself, it is in some way, which we do not understand, what it must be to supply reality to everything having borrowed reality. Thus, while we do not know what the Other is, but only what it is not, we do know that things of our experience and we ourselves are related to it, and that, in a way beyond our comprehension, it has in itself what it must have to sustain this relationship (see S.t., 1, q. 12, a. 12; S.c.g., 2, 11–14).

Do we have reason, even apart from faith, to think of this Other as quasi-personal? I think we do (see DS 3892/2320). While we must deny that it either is a mere object or a personal subject like ourselves, entities having borrowed reality depend upon the Other in a way somewhat similar to that in which free choices depend upon the person whose choices they are. For no one can choose freely if there is a sufficient reason apart from the choice for making it, and the Other cannot be the principle of all else if there is a sufficient reason apart from its causing things for them to have the borrowed reality they enjoy. On the basis of this similarity, we are entitled to think of the Other as if it were a free agent, and so as intelligent, for choice presupposes understanding of options.²⁰

At this point it becomes clear that the “Other” about which we have been talking can only be the God in whom we believe: he who freely creates heaven and earth, things visible and things invisible (see 1 Cor 8.4–6).

However, even the characterization of God which is provided by Christian faith is not a description of him in himself but an understanding of him only insofar as he draws us into personal relationship with himself in the order of salvation. Once this point is understood, one realizes that it is a mistake to take expressions which Christians use in talking about God to have precisely the same meaning they would have in uses outside the context of faith.

Nonbelievers constantly make this mistake. For example, they ask how Christians can reconcile their belief that God is a good and loving Father with all the evil and misery in the world. Again, they ask how human persons can be free if God causes everything and directs all things according to the plan of his providence. Believers sometimes make these same mistakes. Some believers also wonder whether the reality of humankind’s personal relationship with God in the order of salvation does not entail that God mutually depends on his creatures.

While a great deal can be said about these questions, the fundamental principle for replying to them is that they all assume that one knows God in himself, that one’s thought and talk about him is not after all very different from one’s thought and talk about everything and everyone else.²¹

We Christians do not know how to reconcile our belief in God’s goodness with our experience of evil. We do know that we do not understand God and cannot expect to justify his ways (see Jb 42.2–6). We also believe that in the death and resurrection of Jesus, God gives us a sign of his love which does not lessen the reality of evil but does promise to overcome it (see Rom 8.18–39; Jn 11.17–44).

Similarly, we do not know how God can cause the very reality of our free choices without determining what we choose, nor do we know how his providential design can include our lives without reducing us to the status of puppets playing roles in a drama in no way our own. But the difficulties dissolve if we keep in mind that we do not understand God’s causality and providential direction. God “causes” in a unique sense; his plan is not the merely superhuman design of a grand puppet master (see Rom 11.33–36). The life of good deeds is a gift of God’s grace (see Eph 2.10), yet we can choose either life or death (see Sir 15.11–20).²²