1. Practical reasoning has two phases, one concerned with what might be done, the other with what ought to be done. Although these phases are not usually separated in practice, for purposes of analysis this question and the next will consider the principles of practical reasoning in general (what might be done). Good and bad people alike use these principles in considering what they might do. Then, questions E through H will consider moral principles, the starting points for thinking out what one ought to do—that is, for making judgments of conscience.
2. Even in its general phase, practical reasoning is thinking and judging about what is to be, not about what already is.19 It does not simply report and explain; it entertains possibilities and projects lines of action (see S.t., 1, q. 79, aa. 11–13; 2–2. q. 47, a. 2). It is within the wider context of this first phase of practical thinking that moral thinking takes place, since moral reflection is concerned with what is to be done and is not to be done. Even retrospective moral thinking—as when one examines one’s conscience—is concerned with what was to have been done or avoided.
3. According to St. Thomas, the very first principle of practical reasoning in general is: The good is to be done and pursued; the bad is to be avoided (S.t., 1–2, q. 94, a. 2). This is a directive for action, not a description of good and evil. “Good” here means not only what is morally good but whatever can be understood as intelligibly worthwhile, while “bad” refers to whatever can be understood as a privation of intelligible goods. Thomas’ formulation—“Good is to be done and pursued” rather than “Do good!”—suggests that he thinks this principle extends to and governs all coherent practical thinking.20
Since this very first principle is so extremely broad, of what use is it? It does not settle what is good and bad morally. Even immoral choices and their rationalizations depend on this principle, for the immoral choice is not insane, and though arguments for it are unreasonable, they are understandable. What the first practical principle does provide is a foundation for practical thinking.
The first principle of practical reason directs thinking toward the fulfillment which is to be realized in and through human action. It concerns anything a person can understand that would make a possible course of action seem appealing and worth deliberating about, or make it seem unappealing and perhaps to be excluded from further consideration. All human practical reflection—whether it leads to morally good action, to bad action, or to no outcome at all—presupposes the first practical principle.
4. The first principle of practical reasoning is a self-evident truth. One understands it to be true as soon as one understands its terms. Although someone might suggest that for this very reason it is simply a matter of juggling words and tells one nothing at all, this is not the case. True, the first principle does not say what is good and what is to be done, but it does play an important role. To explain this role, St. Thomas compares the first principle of practical reasoning with the principle of noncontradiction.
To understand the meaning of the terms of a principle is not only to know something about words; it is also to have some knowledge of the realities to which the words refer by way of concepts. The very first principle of practical reasoning is a grasp upon the necessary relationship in existential reality between human goods and appropriate action bearing upon these goods.
This necessary relationship is not one we find in the world, since we do not find our own actions in the world; rather we put them there. What the first principle of practical reason tells us is that we must act—we must do things—to be fully the human persons we can and ought to be. In telling us this, the first principle provides human fulfillment as the basis for all of the normative demands which reason ever will make upon us. When at a later stage of practical reflection one wonders, “But why should I do this?” one is asking about the intelligible good to be achieved. One asks this because one knows one’s action would be absurd if it were not directed to some good or other.
To say this is not to exclude that in a particular case the right answer to “Why should I do this?” might be “Because God wills it, as the Church teaches.” Such an answer is not ultimate. It assumes that what God wills is wise, and that his wisdom orders all things to good (see Wis 8.1; DS 3003/1784; DH 3). It also assumes that it is humanly good to trust and obey God, who has shown his love and faithfulness—for example, in the resurrection of Jesus (see DS 3009/1790).
5. The principle of noncontradiction states that the same thing cannot both be and not be at the same time and in the same respect. It asserts the intrinsic relationship between reality and its own definiteness. One cannot consciously proceed to think and talk in disregard of the definiteness of reality. In this sense, the principle of noncontradiction always controls one’s thinking. Yet one can find oneself in a muddle or talking nonsense, and then the principle of noncontradiction makes its demand.
6. Similarly, the first principle of practical reasoning articulates the intrinsic, necessary relationship between human goods and appropriate actions bearing upon them (see S.t., 1–2, q. 94, a. 2; cf. q. 90, a. 1; q. 99, a. 1; 2–2, q. 47, a. 6). In thinking and speaking about what one might do, it is impossible to disregard entirely the goods and bads to which one’s possible acts would be relevant. Thus the first principle of practical reasoning always controls practical thinking. Yet one can find oneself doing something which cannot attain any intelligible good; then the first principle makes it clear that one’s action is pointless and this leads to a cessation of effort. Thus the principle is normative, even though it does not specify the relationship of actions to goods in such a way that deliberation and choice among possibilities are at all limited.
7. In scholastic natural-law theory, the first principle of practical reasoning was misunderstood, formulated not as St. Thomas did but as a most general moral imperative: Do good and avoid evil. However, the first principle is not a moral norm; it governs morally good and morally bad thinking alike. Moreover, an imperative to do good and avoid evil would not be self-evident. Confronted with this command, one could reasonably ask: Why?
19. Anthony Battaglia, Toward a Reformulation of Natural Law (New York: Seabury Press, 1981), systematically ignores both the distinction between the two phases of practical reasoning and that between the theoretical and the practical. Overlooking the latter, he thinks that “good is to be done and evil is to be avoided” means that “ordinary human beings ordinarily want to be good” (5; cf. 63) and that natural law properly is a de facto conformity of man to eternal law, which synderesis and inclination only bring us to know (51). Except for a suggestion that social practices should be established by consensus rather than force (108, 135), he also overlooks the distinction between the two phases of practical reasoning and accepts a thoroughgoing cultural relativism (132–35) as well as a reduction of moral judgment to a process analogous to aesthetic intuition (79, 108). To impose all this on St. Thomas, Battaglia has to make him out to be a sceptic. Thomas’ theory of analogous predication is distorted to mean that “our knowledge is analogical—neither wholly true nor wholly false” (33; cf. 41, 101, 116). Moreover, Thomas’ theory of morality is reduced to a simple pragmatism in which the good is what works and what has worked in the past (72, 128–32).
20. See Germain G. Grisez, “The First Principle of Practical Reason: A Commentary on the Summa theologiae, 1–2, Question 94, Article 2,” Natural Law Forum, 10 (1965), 181–86. Also: Ignacio de Celaya, “La Sindéresis, Principio de Rectitud Moral,” in Etica y Teología ante la crisis contemporánea: I simposio internacional de Teología de la Universidad de Navarra, ed. J. L. Illanes et al. (Pamplona, Spain: EUNSA, 1980), 127–43.