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Thomas Aquinas on Logic, Being, and Power, and Contemporary Problems for Divine Omnipotence


I discuss Thomas Aquinas’ views on being, power, and logic, and show how together they provide rebuttals against certain principal objections to the notion of divine omnipotence. The objections I have in mind can be divided into the two classes. One says that the notion of omnipotence ends up in self-contradiction. The other says that it ends up contradicting certain doctrines of traditional theism. Thomas’ account is frequently misunderstood to be a version of what I call a ‘consistent description’ account of omnipotence, which is a standard contemporary account. That account of omnipotence, however, succumbs to certain contemporary objections. Thomas’ account withstands those objections because of his view of logic and, specifically self-contradiction. Moreover, a certain thesis found in Thomas’ understanding of God, but almost entirely absent from contemporary debates about omnipotence, is that God is not just a being, but the source of being. This thesis, I argue, puts Thomas’ account in a position that differs greatly from many contemporary accounts since the scope of possibility, and specifically the scope of what possible powers there are, is ultimately grounded in God’s being. Further still, many contemporary accounts of omnipotence do not seek to establish substantive account of power itself. Thomas, by contrast, has a robust and independent account of what power is. And that account informs his account of what it is to have all powers, or to be omnipotent, in a way that makes his account resistant to contemporary objections. Against contemporary objections, Thomas’ account of omnipotence can sustain the claim that God can do all things.

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  1. Anonymous (2012), p. 3.

  2. Peter T. Geach (1973), pp. 7–8.

  3. Classical theism is the view of God that has prevailed in Western culture. It holds that God is the metaphysically ultimate being, and has the attributes of aseity, simplicity, omniscience, omnipotence, and perfect goodness. Philosophically, it is rooted in Aristotelian and Neo-platonic thought. And it has stood as the conception of God for the great monotheistic religions, Judaism, Christianity, and Islam.

  4. See, for example, Thomas Metcalf (2004), pp. 294–295.

  5. In the literature on causal powers, there is a general agreement that a power is distinguished by what is commonly called the ‘manifestation’ of the power. There is, however, a diversity of opinions about whether a power’s manifestation is to be understood as the effect of the power (See, for example Jennifer McKitrick (2010), p. 74), or simply its operation (See, for example, George Molnar (2003), p 195). There is also a related controversy about whether a power can have only one manifestation or multiple manifestations (See, for example, Alexander Bird (2007), p. 21).

  6. Geach (1973), p. 9.

  7. This is not to say that inconsistency and self-contradiction are the same thing. See John Williams (1981).

  8. In general, what philosophers call ‘states of affairs’ are object-attribute compounds such as, e.g., snow’s being white. It is according to that general, contemporary sense (often given by examples similar to the one just given) that I use the expression throughout the paper. And as I point out in the course of the paper, the contemporary sense of ‘state of affairs’ tracks nicely Thomas’ understanding of subject-accident composites.

  9. Some contemporary formulations are constructed to exclude token states of affairs, acts, or tasks. For example See Joshua Hoffman and Gary S. Rozenkrantz (2008), pp. 169–170. Since, generally, objections to omnipotence do not cite such cases, in this paper I set worries about them aside.

  10. For example of this interpretation of Thomas, See Geach (1973), p. 12; See also Walter Glannon (1994), p. 81.

  11. This way of posing the argument comes from Theodore Drange (2003), who has modified a version of this argument presented by Gale (1991), p. 18. The argument here is formulated as a reductio, but it need not be so formulated. C. Wade Savage (1967), for example, possesses it as a dilemma, which argues that for any being, there must be some task it cannot perform, and therefore, omnipotence is logically impossible.

  12. The aim of Drange’s article, in fact, is to consider such a move.

  13. Geach (1973), p. 14. For a similar move, See also Kenneth Pierce and Alexander Pruss (2012), p. 404.

  14. Geach (1973), p. 14.

  15. Pierce and Pruss (2012), p. 404.

  16. Earl Conee (1991) claims that this conception of omnipotence is the ordinary one.

  17. Geach (1973), p. 11.

  18. Ibid., p. 9.

  19. See Williams (1981), p. 600.

  20. Geach (1973), p. 10.

  21. Ibid., p. 9.

  22. Conee (1991), p. 457.

  23. See Pierce and Pruss (2012) who argue that accidental omnipotence is incoherent as well (See p. 404).

  24. Wes Morriston (2001), p. 9.

  25. Ibid.

  26. Ibid.

  27. Hoffman and Rosenkrantz (2008), p. 167.

  28. See Geach (1973), p. 12.

  29. ST (1948) Ia q25 a3 co.: ‘Quaecumque igitur contradictionem non implicant, sub illis possibilibus continentur, respectu quorum dicitur Deus omnipotens. Ea vero quae contradictionem implicant, sub divina omnipotentia non continentur, quia non possunt habere possibilium rationem.’ Translations are my own, except were indicated.

  30. Ibid.: ‘Hoc igitur repugnat rationi possibilis absolute … quod implicat in se esse et non esse simul.’

  31. Ibid.: ‘Id enim quod contradictionem implicat, verbum esse non potest, quia nullus intellectus potest illud concipere.’

  32. See ST (1948) Ia q34 a1 co.: ‘The clearest and most common sense is when it is said of the word spoken by the voice; and this proceeds from an interior source as regards two things found in the exterior word—that is, the vocal sound itself, and the signification of the sound. For, according to the Philosopher (Peri Herm. i) vocal sound signifies the concept of the intellect.’ (tans. Fathers of the English Dominican Province).

  33. De Ente (1968) I.4: … etiam si illud in re nihil ponat.’ Cf. In Met. (1995) V.9.896: ‘… the intellect considers as a kind of being something which is in itself a non-being, such as a negation and the like …’

  34. ST (1948) Ia q4 aa2-3.

  35. In Met. (1995) V.9.889.

  36. In Phys. (1995) III.1.280.

  37. DPN (2014) 1: ‘… because form makes being in act, it is said that a form is act.’ (… forma facit esse in actu, ideo forma dicitur esse actus.)

  38. In Met. (1995) IX.8.1857: ‘… act is the end of potency …’ (… actus est finis potentiae …)

  39. See In Met. (1995) V.9.897.

  40. DPN (2014) 1: ‘… being is twofold: namely, essential or substantial being, such as to be a man, and this is being simpliciter. But the other is accidental being, as to be a white man …’ (… duplex est esse: scilicet esse essentiale rei, sive substantiale ut hominem esse, et hoc est esse simpliciter. Est autem aliud esse accidentale, ut hominem esse album …)

  41. See In Met. (1995) X.10.2121; cf. XII.1.2420.

  42. Some privations, such as what cold is to heat, are, for Thomas, not utter absences of form, but rather imperfect realizations of some form. See DGen (1964) I.8.62.

  43. DPN (2014) 2.

  44. See In Met. (1995) V.18.1040–1044.

  45. See In Met. (1995) IV.4.574.

  46. Ibid.: ‘… quae quidem non inveniuntur in rerum natura, sed considerationem rationis consequuntur.’

  47. See SCG (1975) I.71.3.

  48. SCG (1975) I.53.3: ‘… eo quod intellectus intelligit indifferenter rem absentem et praesentem.’

  49. SCG (1975) I.36.2: ‘… non enim intellectus modum quo intelligit rebus attribuit intellectis.’

  50. See In Met. (1995) IV.1.535–536.

  51. An example might be helpful. Kindergarten teachers know (and I speak here from experience) that a typical kindergartener who is learning to do sums can, at first, know a sum only by counting. In time, they begin to infer the sum by induction. There arrives a point in cognitive development, however, when a child comes to simply see what the sum of two numbers is. It would be a cognitive impairment to not ever be able to see this, but to have to rely on counting or inductive inference.

  52. See, for example, ST (1948) Ia q13 a2 on the way names are applied analogously to God.

  53. In Met. (1995) IV.6.603: ‘… opinetur simul duo contradictoria esse vera, opinando simul idem esse et non esse.’

  54. ST (1948) Ia q25 a3 co.: ‘Dicitur autem aliquid possibile vel impossibile absolute, ex habitudine terminorum.’

  55. Ibid.: ‘… possibile quidem, quia praedicatum non repugnat subiecto … impossibile vero absolute, quia praedicatum repugnat subiecto.’

  56. See Roderick M. Chisholm (1966), p. 71.

  57. See SGC II.25.14.

  58. Consider In Met. (1995) IV.6.601 where Heraclitus is said to have espoused self-contradictions so that others thought he believed them. Though Aristotle and Thomas say that it is impossible that Heraclitus believed them, what this shows is that what he said was understood by others, for only thereby could they wonder whether he believed what he said.

  59. Geach (1973), p. 13.

  60. See SCG (1975) I.84.3–4.

  61. QDP (2004) q1 a3 co.: ‘… for an affirmation and a negation to be at once cannot have the nature of being, nor even of non-being.’ (… quod est affirmationem et negationem esse simul, rationem entis habere non potest, nec etiam non entis.)

  62. See SCG (1975) II.25.19.

  63. SCG (1975) II.25.10: ‘Deus … non posse quicquid est contra rationem entis inquantum est ens, vel facti entis inquantum est factum.’

  64. QDP (2004) q1 a3 co.: ‘… omnis actio activae potentiae terminatur ad esse.’

  65. SCG (1975) II.25.6. ‘Defectus omnis secundum privationem aliquam est.’

  66. See SCG (1975) I.95. This is not to say that, for Thomas, moral failure ultimately is a rational error, only that every moral failing involves an ‘error in reason’ (Voluntas nunquam ad malum fertur nisi aliquo errore in ratione).

  67. QDP (2004) q3 a6 ad1: ‘… operatio peccati, quantum ad id quod habet de entitate et actualitate, refertur in Deum sicut in causam.’

  68. SCG (1975) II.22.8: ‘… divina virtus non determinetur ad aliquem effectum, sed simpliciter omnia potest: quod est eum esse omnipotentem.’

  69. See for example, Willard Quine (1953), David Lewis (1973), and Timothy Williamson (2013).

  70. See Alvin Plantinga (1974).

  71. See In Met. (1995) Prologue.


  • Anonymous (2012). The penny catechism: a catechism of christian doctrine. Charlotte, NC: TAN Books.

  • Bird, A. (2007). Nature’s metaphysics: laws and properties. Oxford: Oxford University Press.

  • Chisholm, R. (1966). Theory of knowledge. Englewood Cliffs, NJ: Prentice-Hall, Inc..

    Google Scholar 

  • Conee, E. (1991). The possibility of power beyond possibility. Philosophical Perspectives, 5, 447–473.

    Article  Google Scholar 

  • De Ente. — (1968). On being and essence, Armand Maurer (trans.), Pontifical Institute of Mediaeval Studies, 2 revised edition.

  • DGen. — (1964) Exposition of Aristotle’s treatise on generation and corruption, Book I, cc. 1–5, Pierre Conway and R.F. Larcher, trans. (Columbus, Ohio: College of St. Mary of the Springs).

  • DPN — (2014). “On the principles of nature,” Eleonore Stump and Stephen Chanderbhan (trans.) in Jeffrey Hause and Robert Pasnau (eds.), Thomas Aquinas, Basic Works (Indianapolis: Hackett), pp. 2–13.

  • Drange, T. M. (2003). Gale on omnipotence. Philo, 6(1), 23–26.

    Article  Google Scholar 

  • Gale, R. M. (1991). The nature and existence of God. Cambridge: Cambridge University Press.

    Google Scholar 

  • Glannon, W. (1994). Omnipotence and the transfer of power. International Journal for Philosophy of Religion, 36(2), 81–103.

  • Geach, P. (1973). Omnipotence. Philosophy, 8(183), 7–20.

    Article  Google Scholar 

  • Hoffman, J., & Rozenkrantz, G. S. (2008). The divine attributes. Oxford: Wiley-Blackwell.

  • In Met. — (1995). Commentary on Aristotle’s metaphysics, John P. Rowan (trans.) (Notre Dame: Dumb Ox Books).

  • In Phys. — (1995). Commentary on Aristotle’s physics, Richard J. Blackwell, Richard J. Spath, and W. Edmund Thirlkel, (trans.) (Notre Dame: Dumb Ox Books).

  • Lewis, D. K. (1973). Counterfactuals. (Oxford: Blackwell Publishers and Cambridge, MA: Harvard University Press).

  • McKitrick, J. (2010). Manifestations as effects. In A. Marmodoro (Ed.), The metaphysics of powers: their grounding and their manifestations (pp. 73–83). London: Routledge.

  • Metcalf, T. (2004). Omniscience and maximal power. Religious Studies, 40(3), 289–306.

    Article  Google Scholar 

  • Molnar, G. (2003). Powers: a study in metaphysics. Oxford: Oxford University Press.

  • Morriston, W. (2001). Omnipotence and the Anselmian God. Philo: A Journal Of Philosophy, 4(1), 7–20.

    Article  Google Scholar 

  • Pierce, K., & Pruss, A. (2012). Understanding omnipotence. Religious Studies, 48, 403–414.

  • Plantinga, A. (1974). The nature of necessity. Oxford: Oxford University Press.

    Google Scholar 

  • QDP — (2004). Quaestiones desputatae de potentia dei, English Dominican fathers, (trans.), Repr. (Eugene: Wipf and Stock).

  • Quine, W. V. O. (1953). From a logical point of view. Harvard: Harvard University Press.

    Google Scholar 

  • Savage Wade, C. (1967). The paradox of the stone. The Philosophical Review, 76(1), 74–79.

    Article  Google Scholar 

  • SCG — (1975). Summa contra gentiles, Book I, Anton C. Pegis (trans.) and Book II, James Anderson (trans.) (Notre Dame: University of Notre Dame Press).

  • ST — (1948). Summa theologiae, Fathers of the English Dominican Province (trans.), Repr. (New York: Benziger Bros.).

  • Williams, J. (1981). Inconsistency and contradiction. Mind, 90, 600–602.

    Article  Google Scholar 

  • Williamson, T. (2013). Modal logic as metaphysics. Oxford: Oxford University Press.

    Book  Google Scholar 

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Clark, E.D. Thomas Aquinas on Logic, Being, and Power, and Contemporary Problems for Divine Omnipotence. SOPHIA 56, 247–261 (2017).

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  • Omnipotence
  • Thomas Aquinas
  • Being
  • Power
  • Logic
  • Contradiction