"The good of the grace of one soul is greater than the good of the nature of the whole universe"
- St Thomas Aquinas Ia IIa, q.24, a. 3, ad 2

— A Commentary on the First Part of St Thomas' Theological Summa

by Reginald Garrigou-Lagrange, O. P.


Second article: whether it can be demonstrated that God exists

State of the question. Posited that God's existence is not self-evident to us, the question is whether it can be demonstrated. The difficulty is threefold: 1) that God's existence is the first article of the Creed, "I believe in God," and it is not the articles of the faith but only the preambles to the articles that are demonstrated; (2) , that the medium of demonstration is the essence of a thing, and we do not know God's essence; (3) and that God's existence cannot be demonstrated from effects, for there is no proportion between the finite effect and the infinite God.

This last difficulty is variously proposed by modern agnostics, whether they are positivist empiricists such as Stuart Mill and Spencer, or idealists such as the Kantians. According to the positivists, we have indeed knowledge only of phenomena, and of their laws or constant relations. According to Kant, the theoretical reason cannot prove God's existence, because the principle of causality is only a subjective law of our mind; at least it is not clearly seen to be a law of real being, for the notion of causality seems to be a subjective category of our understanding, useful indeed for the subjective and for us necessary classification of phenomena, but without any ontological validity, and a fortiori without any transcendent validity for acquiring a knowledge of the transcendent Cause.

According to Kant only the practical reason proves God's existence with a certainty that is objectively insufficient but subjectively sufficient, namely, from the postulates of moral action. Kant indeed says: It is a synthetic a priori or subjectively necessary principle that the just person is deserving of happiness. But the just do not enjoy permanent happiness in this life. Therefore God the rewarder must exist, who is the only one who in the other life can effect a permanent union between virtue and happiness. This is not theoretically demonstrated, but it is reasonably believed by moral faith.

Likewise the traditionalists or fideists, condemned in the year 1855 (29) held that reason left to itself (without the aid of primitive revelation handed down by traditions among the nations) cannot demonstrate God's existence. Already in the Middle Ages Nicholas of Ultricuria (30) upheld fideism, denying the real validity of reason, especially the real validity of the principle of causality.

The reply is that God's existence can be demonstrated by effects known to us.

1) The authority of Scripture is proof of this, for we read: "The invisible things of Him from the creation of the world are clearly seen, being understood by the things that are made." (31) But this would not be the case if, by the things that are made, God's existence could not be demonstrated. All Scholastics, except such radical nominalists as Nicholas of Ultricuria, so understood this and similar texts of Holy Scripture.(32) The above-mentioned text from the Epistle to the Romans is quoted by the Vatican Council in defining against traditionalists, fideists, Kantians, and positivists that "the same Holy Mother Church holds and teaches that God, the beginning and end of all things, may be known for certain by the natural light of human reason by means of created things; for the invisible things of Him from the creation of the world are clearly seen, being understood from the things that are made." (33) The same is defined in the corresponding canon.(34)

Moreover, there is a better explanation of this text against the agnostics of our times in the antimodernist oath that expresses the faith of the Church in the following words: "I (name) firmly hold as true and accept everything which the infallible teaching authority of the Church has defined, maintained, and declared, especially those points of doctrine which are directly contrary to the errors of the present time. And first of all I profess (profiteor) that God, the beginning and end of all things, can be known for certain and proved by the natural light of reason, that is to say, through the visible works of His creation, just as the cause is made known to us by its effects." (35) The word "profiteor" in the Latin of this oath expresses a profession of faith, and this is especially evident from what is stated a little farther on, for we read: "Thirdly, I firmly believe that the Church was instituted by the true and historic Christ." We have elsewhere fully examined each word of the above quoted dogmatic definition of the Vatican Council, which is explained by this oath.(36)

In the definition as explained by the oath we have the condemnation of the fideism of the traditionalists whose theses had already been proscribed.(37) Kantianism is likewise condemned.(38) Moreover, the Church declares that God's existence can be proved not only from the postulates of practical reason, but from the visible effects. Nor is the proof founded in the primacy of the immanent method of sufficient weight, because the proof does not give us objectively sufficient certitude. This has already been shown at length in another work.(39)

Hence the Church in some measure gives her approbation to the validity of the a posteriori traditional proof of God's existence, but she neither approves nor condemns St. Anselm's argument and Descartes' theory of innate ideas.
Moreover, the above-quoted definition as given by the Council is concerned with "the existence of the true God, the beginning and end of all things." (40) It is not, however, formally defined that reason can demonstrate creation out of nothing, but that it can demonstrate the existence of God, the first Cause, and that the divine attributes of infinity, eternity, supreme wisdom, providence, and sanctity are included in this notion. To avoid the charge of heresy, therefore, it would not suffice to say with several agnostics that reason can demonstrate the existence of some first eternal cause, which however is perhaps an immanent principle in the world, neither transcendent nor personal, that is to say, intelligent and free. This would not be proving the existence of the true God.

It is not defined whether reason alone can deduce explicitly the proper attributes of the true God, especially infinity. However, Bautain had to acknowledge his acceptance of the following proposition: "Human reasoning can with certainty prove the existence of God and the infinity of His perfections. Faith, being a supernatural gift, presupposes revelation, and hence cannot be consistently invoked to prove the existence of God against an atheist." (41) Hence, if the denial of the demonstrability of God's infinity is not heretical, it is at least erroneous.

Finally, the aforesaid definition is concerned not with the fact but with the possibility of proving God's existence. It is defined to be physically possible even in the state of fallen nature.(42) Moral possibility, however, or a possibility that presents no great difficulty, is proximate to the faith, this being the common teaching of the theologians; otherwise the Scripture would not have said: "But all men are vain, in whom there is not the knowledge of God: and who by these good things that are seen could not understand Him that is, neither by attending to the works have acknowledged who was the workman." (43) At least from the order to be seen in the world there is no difficulty in concluding as to the probability of a supreme Ordainer, and then man is bound to make further inquiries. If he does not do so, his ignorance is not entirely involuntary or invincible. Therefore theologians commonly reject the possibility of invincible ignorance about the existence of God as the author of the natural moral law. The first principle of this law, namely, "good must be done, evil must be avoided," (44) is known without difficulty; and there can be no law without a lawgiver, nor can there be any passive designing without active designing, or without a supreme Designer.

Hence the following proposition was condemned as temerarious and erroneous, namely, the proposition about a philosophical sin that would be against right reason and yet not an offense against God, because it would be committed "by a man who either has no knowledge of God, or does not advert to Him." (45)

Revelation is morally necessary, however, as the Vatican Council says: "that such truths among things divine as of themselves are not beyond human reason can, even in the present condition of mankind, be known by everyone with facility, with firm assurance, and with no admixture of error." (46) These are the principal arguments drawn from authority.

2) The conclusion is proved by reason. In the body of the article St. Thomas: (1) distinguishes between two kinds of demonstration, one being a priori, the other a posteriori; (2) he shows that the demonstration a posteriori, or from the effect, is valid; and (3) he shows how this applies to the demonstration of God's existence.

1) Demonstration is of two kinds. The a priori demonstration is through the cause, and it assigns the reason for which of the thing demonstrated. Each of the four causes can give us this kind of demonstration. Thus the spirituality of the soul is assigned as the reason for its incorruptibility (formal cause); likewise, man is mortal from the fact that he is composed of contraries (material cause); also that we are free is proved from the fact that we are endowed with reason and have knowledge not only of particular but also of universal good (directive formal cause). In like manner, the necessity of the means is demonstrated a priori from the end; thus grace is necessary for the supernatural vision of God. The same is true of the efficient cause. Given the cause in the act of causing, as in the case of the sun illuminating, then the effect follows. Thus this kind of demonstration can be effected by means of the four causes.

Demonstration through the effect, however, is called a posteriori, because the effect is something posterior to the cause; but sometimes it is previously known to us. This demonstration shows that the cause is, quod vel quia est, for in the Latin terminoloy of the Scholastics, quia est means the same as quod est. Thus it is called demonstratio quia in opposition to demonstratio propter quid. It is therefore a demonstration by means of those things that are previously known to us. The order of invention is then ascendant, whereas the order of things is descendent.

It must at once be noted from the reply to the second objection that, "in demonstrating God's existence from His effects, we must take for the middle term the meaning of the word 'God.' " This means that we must begin with the nominal definition of God, since by the name "God" is understood the supreme Cause, the most perfect Being, the supreme Ordainer, and the question is whether the supreme Cause exists.


Index Top


17. Meditations et reponses aux objections.

18. Monadologie, § 45; Meditation sur les idees, p. 516.

19. Summa theol., Ia, q.25, a.6.

20 Ibid., q.4, a.3; q.88, a. 3.

21.Ibid., q.4, a.3; q.13, a.5.

22. Revue de Phil., December, 1909; Ontologia, pp. go f.

23. Summa theol., La, q.25, a.6.

24. Father Lepidi admitted a certain naturally innate idea of God, inasmuch as the soul, since it is according to God's image, received, at the moment of its creation, a certain irradiation from God, or a confused notion of the Creator.
But this not proved, nor can it be proved. Moreover, according to the principles of Thomism, all our ideas are the result of abstraction from sensible things (cf. Summa, Ia, q.84, a.3, 6).

25. Ibid., q.3, a.8, "Whether God enters into the composition of other things."

26. See Syllabus of Pius IX, Denz., no. 1701.

27. Denz., nos. 1659-65.

28. Ibid., nos. 1649-52.

30. Ibid., no. 553 f.

31. Rom. 1: 20.

32. Wis., 13: 1-5.

33. Denz., no. 1785.

34. Ibid., no. 1806.

35. Ibid., no. 2145.

36. See God, His existence, 1, 8-39.

37. Denz., nos. 1622, 1650.

38. Cf. Acta Concilii, Collectio Lacencis, VII, 130, which explains the word "certo." The council is speaking of objectively sufficient certainty and not solely of subjectively sufficient certainty, as Kant said it was.

39. Cf. God, His Existence, 1, 40-60. Maurice Blondel in his "L'Action," pp. 437 f., writes: "The knowledge which before option was purely subjective and propulsive, after the choice becomes privative and constitutive of being (according as the free choice is good or bad).... The second kind of knowledge ... is no longer merely a subjective state of mind; for instead of positing the problem in the practical order ... it directs the attention to what is an accomplished fact (in the free choice), to that which is. Thus it truly is an objective (but practical) knowledge, even though it is obliged to admit a deficiency in action." But quite recently Blondel made a retractation of this last chapter of his first work, and
he is now more in agreement with the traditional teaching.

40. Denz., no. 1785.

41. Ibid., no. 1622.

42. GE Vacant, Etudes sur le Concile du Vatican, I, 28, 289, 673.

43. Wis. 13:1.

44. Summa theol., Ia IIae, q.94, a.2.

45. Denz., no. 1290.

46. Ibid., no. 1786. For an explanation of this, consult author's commentary on q. 1, a. 1.


"A man should keep himself down, and not busy himself in mirabilibus super se."

St Philip Neri

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"Obedience is the true holocaust which we sacrifice to God on the altar of our hearts."

St Philip Neri

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"What good does it do to speak learnedly about the Trinity if, lacking humility, you displease the Trinity? Indeed it is not learning that makes a man holy and just, but a virtuous life makes him pleasing to God. "

Thomas á Kempis

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