Editor’s note: The premier benefit of working for a college is the opportunity to take classes. This semester, I am taking a theology class, and to the extent that my written submissions are deemed canonical and pertinent to Motu Proprio, excerpts will appear here under the TH200 tag after submission and grading. Formal errors both accidental and deliberate—such as the mandated use of “MLA style”—will be corrected, but the substance will be presented intact.

We tend to think of faith and doubt as opposites. But Fischer & Hart suggest that, to the contrary, doubt has religious utility: “[D]oubts,” they say, “are a natural part of any faith that is alive and growing.” 1 They suggest that “[w]hat feels like the loss of faith may in fact be a movement out of the limits of one form of faith,” insofar as disillusionment can lead to reevaluation. 2 We are asked to evaluate this notion.


William Lord Kelvin believed that it is only “[w]hen you can measure what you are speaking about and express it in numbers [that] you know something about it,” for “when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meager and unsatisfactory kind: it may be the beginning of knowledge, but you have scarely in your thoughts advanced to the stage of science.” 3 In the broadest sense of the word “doubt,” which might be summarized as the absence of certainty, it might be said that anything that we do not know with that kind of precision must be thought in doubt: Anything that we cannot know with such certainty is, perforce, uncertain.

But this is too general to say much of immediate use. “No one has ever seen God” 4; neither, though, has ever seen Jupiter’s core, and so its composition must perforce be reckoned “uncertain” in the sense just described. But who would say that she doubts, per se, Arthur C. Clarke’s vignette about its diamond core? 5 (Later, we will call this kind of doubt benign involuntary doubt.) N.T. Wright observes that science reasons and infers that which it doesn’t know from that which it does, 6, and of a piece with this is the Roman Catechism, which observes that “[t]he knowledge derived through faith must not be considered less certain because its objects are not seen; for the divine light by which we know them, although it does not render them evident, yet suffers us not to doubt them.” 7

Reasoned inference alone, however, does not seem to amount to the “convergence of probabilities” of Newman, 8 let alone the hard certainty of Kelvin. Wright observes that astronomers, having read their empirical data on the planets they knew, and acting on the certainty that they understood the physics involved, concluded that physics called for the existence of yet-unseen planets, 9 and they were right. But what that vignette elides is that the astronomers’ predecessors had read their empirical data on the planets that orbited the Earth (so they believed), and, acting on the same kind of certainty that they had understood the physics involved, concluded that the physics called for the planets to engage in an epic ballet of circles and retrograde motion that they called “epicycles.” 10 We now ridicule this approach as “adding epicycles”: If the observational data don’t fit the theory, we would rather add layer upon layer of complexity to mediate between the data and the theory than reconsider the theory. 11 So: When we run on reasoned inference, we are sometimes discovering new planets, but sometimes we’re adding epicycles. And other than hindsight, how can we know the difference? Human arrogance always wants to believe that it’s the former, but is that really “certainty”?


It seems that we must have a more precise account of doubt’s content before we can evaluate its utility.

The word “doubt” can mean many things. It derives from the latin dubito—to question, to waver in opinion, to be uncertain, to ponder or deliberate, to be perplexed 12—and in its broadest sense refers to a lack of certainty. It can mean to be unsettled, uncertain, undecided, hesitant, or wavering in opinion. 13 It can mean to lack conviction about or to be skeptical of something, to tend toward disbelief. 14 Suspicion and even mistrust are in its ambit. 15 But it can also mean simply a state of being undecided. 16

At the other extreme,  the narrowest and most technical definition of which I am aware is that of Rahner & Vorgrimler, who insist that “doubt,” in a theological sense, means only “the deliberate suspension of personal assent to knowledge of which the import and … the basis were and are known to the doubter,” that is, “the free and morally-culpable suspension of assent to the truths of faith.” 17 They would withhold the label “doubt” from non-compelling difficulties one might encounter with adhering to an idea or proposition, still less from a mere state of “questioning,” that is, of “seek[ing] further and fuller knowledge.” 18

Everything else falls somewhere in between; two more examples will suffice. There is a sense in which doubt is meant in the definition of the sin of pusillanimity: “A person does not abandon God by this sin, but simply does not have enough hope. He doubts whether God has forgiven his past sins, and he is afraid that he will not get enough grace from God in the future to work out his salvation.” 19 It may also be a reflex, the product of what St. Thomas Aquinas described as “wonder rather than of unbelief.” 20 Aquinas suggests that we read the shock of the Blessed Virgin Mary at the Annunciation in this sense, and the Catechism of the Catholic Church suggests the same about the doubts of St. Thomas the Apostle. 21


So this is something of a menagerie. We have a term that seemed fairly precise from a distance, but turns out, on closer inspection, to cover considerable ground. Is there any kind of order or system that we can impose on it?

Let us start from the proposition that the fundamental notion of the word “doubt” is uncertainty. The Catechism of the Catholic Church proposes a useful distinction that divides the family of doubt into two genera: Doubts voluntary and involuntary.

Voluntary doubt about the faith disregards or refuses to hold as true what God has revealed and the Church proposes for belief. Involuntary doubt refers to hesitation in believing, difficulty in overcoming objections connected with the faith, or also anxiety aroused by its obscurity. If deliberately cultivated doubt can lead to spiritual blindness. 22

That is a good start, but we might speciate the genus voluntary doubt. Terminal voluntary doubt is what Rahner & Vorgrimler describe, which strikes me as not very doubtful at all; it seems indistinct from conviction of the contrary proposition. The agnostic doubts; the atheist is convinced! 23 Judicial voluntary doubt, by contrast, is a deliberate suspension of judgment in the face of a difficult question, either because one is studying it or believes that it does not require resolution. Until 1854, for example, the Catholic Church corporately might be said to have been “in doubt” as to the immaculate conception of the Blessed Virgin Mary. Individual Catholics held strong opinions—for example, the Franciscans and Dominicans clashed over it 24—but the Church herself, following the Augustinian maxim in necessariis unitas, in dubiis libertas, in omnibus caritas, did not bind all to a single answer or formulation, leaving the faithful at liberty to follow their own consciences. 25 Thus was allowed the space for understanding to ripen and sharpen. Only with the promulgation of Ineffabilis Deus was the question settled. 26 In this sense, then, the function of an ex cathedra pronouncement might be said to be that by it, a pope says, in voce Ecclesiæ, “we are certain, we are not in doubt on this point,” where “we” means the Church corporately.

We might also speciate the genus involuntary doubt. First, benign involuntary doubt would seem to be a logical consequence of the breadth of religion and the shortness of life. Consider: Calvin’s Institutes sprawls across two dense volumes; Hodge’s Systematic Theology, three; the assembled writings of the Church Fathers, dozens. Tillich’s Systematic Theology runs to hundreds of pages; Aquinas’ Summa Theologica, thousands. Corporately, we have done pretty well! For nearly two millennia, “we” have explored every imaginable nook and cranny the faith, and then some. But what of “me”—the ordinary, individual Christian? Few of us have minutely examined every item of our professed creed. Few of us have extrapolated and weighed every implication, and have called each of the various theological ballgames, such that we are able to affirm every question with total certainty based on our personal evaluation. If we had to develop that level of certainty before deciding to believe, we might spend our entire lives with our noses in the books and never get around to believing! Not for nothing did de Lubac suggest that doubt is not the only thing to be feared in religion: One’s “faith can go down to zero without even being shaken by doubt,” becoming “empty and external,” a great tree of solid appearance disguising an empty trunk. 27 You can spend your entire life thinking and do no better than a child who confesses that her friend Jesus is Lord. 28 It follows that there must lurk in our belief any number of points on which we should not pretend to be entirely, consciously, and deliberately certain, because we have gotten around to examining them only superficially if at all.

Second, conscious involuntary doubt. All of us, surely, have had the experience of learning a religious truth that is difficult for us—that is a hard saying. 29 This is more like the reflexive sense in which we earlier saw Aquinas and the Catechism use the term, and it is perhaps the sense intended by the great Northern Baptist preacher Harry Emerson Fosdick when he memorably observed that doubt is “the hard anvil on which real faith is hammered out.” 30 Unlike the two species of voluntary doubt, the person in this state is neither rejecting a truth nor deliberately suspending judgment on it, pending further study. She is simply wrestling with it. It would be a credulous mind indeed that would accept new information with no delay; that is the sort of mind that immediately clicks “share” on every half-baked yet agreeable Facebook political meme without wondering for a second whether it is true. A mature mind takes its time to greet new arrivals at the doorstep, to size them up and get a sense of who they are and where they are going—which isn’t unfriendly, but nor is it instant.

Finally, we might note that conscious involuntary doubt may be transient or protracted. When a man is grabbed by his lapels and shaken violently by some new truth, it is to be expected that he take some time to recover his composure. Picture the grief of the man told that he has six months to live and there is nothing to be done: We all know the steps. Denial; anger; bargaining; depression; and, eventually, acceptance. This is transient conscious involuntary doubt. It passes—usually. But sometimes we get hung up and stuck in a loop; in a religious context, this means that our doubts fester. That is protracted conscious involuntary doubt. This distinction has a significance to which we shall return momentarily.


To recap, then: We have given “doubt” a general, familial definition, and classified the family “doubt” into two genera and four species: Doubts voluntary (which may be terminal or judicial) and involuntary (which may be benign or conscious).  Can any of these be helpful to faith, as Fischer & Hart suggest?

In the most general sense, in which doubt means uncertainty, an intermediary stage of doubt would seem a logical prerequisite to movement between any given certainty and another. I am far less convinced than Fischer & Hart that doubt can function as a proxy for an openness to new ideas—or, to put it more critically, that certainty betrays epistemic closure. 31 This is akin to the complaint of the dissident theologian Leonardo Boff that “[t]here is no doubt [in Joseph Cardinal Ratzinger], and those who have no doubt are unwilling to engage in dialogue; they are incapable of learning from others.” 32 As the philosopher has said, it is the capacity to entertain an idea without accepting it is a mark of an educated mind. Nevertheless, it would be a mark of intellectual immaturity to sublimate from one belief to a different and incompatible one, and so doubt, in that sense, is a necessary and inevitable fulcrum between two certainties. If the earlier certainty was wrong, one must say that doubt was a part of one’s religious growth.

Now let us consider our various species of doubt. There is certainly no religious utility to terminal deliberate doubt. It is the end of the line. But judicial deliberate doubt may be useful, because, as we have seen, a demand for total certainty on every point would be paralyzing. It is not necessary to rush to conclusions on every question, or to feel that one must have all the answers before saying “yes” to God. We should be able to “make a defense to anyone who asks … for a reason for the hope that is in [us],” 33 but we should not feel that we must be sophisticated enough to survive an interrogation from Lord Kelvin. In this sense, doubt was certainly useful to the salvation of Dag Hammarskjöld: Judicial deliberate doubt seems to have enabled Hammarskjöld to say, in effect (as many of us have), “Lord, I don’t yet understand, but I trust you, and I am yours, and I will learn the rest as we go.” 34

Benign involuntary doubt has no religious utility per se, but insofar as it is potential, insofar as it is an opportunity, the realization that we have it can be useful insofar as it forms an invitation. In 2011, for example, a corrected translation of the Mass changed the words in which the Nicene Creed’s confession that Christ is consubstantialem Patri is rendered in English, from “one in being with the Father” to “consubstantial with the Father.” Catholics who had never had much reason to ponder the phrase were invited to enter more deeply into a mystery that, if we are frank about it, we do not really understand. The believer gradually unpacks belief. Fischer & Hart capture this notion quite well: If I am “drawn to belief in Jesus as a figure of central importance for my life,” surely I must thereafter “reflect on the act of total personal trust I have placed in him.” 35 Thus, “I may turn to theology for answers to certain questions that arise: What is the meaning of the salvation Jesus offers? How can we relate to the human and divine in His life? How are we to understand the miracles of Jesus?” 36 I might have given little or no thought to these questions when I gave the steering wheel to the Savior, and therefore must, despite my faith, have been in a state of benign involuntary doubt on those questions. Piece by piece, I will learn.

By contrast, protracted conscious involuntary doubt is corrosive to faith, for just as the believer gradually unpacks belief, so too the doubter gradually unpacks doubt. Consider the situation of a Catholic who, subsequent to the promulgation of Ineffabilis Deus, cannot shake serious doubts about the dogma of the immaculate conception. The subconscious mind is always working to resolve cognitive dissonances, revolving the puzzle and trying to make straight what seems crooked; if she cannot escape her doubts, her mind is likely to resolve the dissonance in the other obvious way: She will begin to doubt that magisterium has the authority or competence to impose this vexing dogma upon her conscience. But isn’t it always the same way when you pull a loose thread? As the puzzle continues to revolve in her mind, it must eventually occur to her to wonder: Si falsus in uno, incertus in omnibus? If the magisterium lacks the authority and competence to determine that the Blessed Virgin Mary was conceived free of original sin, how can it be trusted to expound the concept of original sin in the first place? And so she herself becomes the authoritative interpreter of scripture, upon which she now places her emphasis, doubting those things where (it seems to her) the magisterium diverges from scripture. The puzzle continues to revolve. In time, it occurs to her that the canon of scripture is underwritten by the magisterium, and if the magisterium lacks the authority and competence to determine that the Blessed Virgin Mary was conceived free of original sin, how can it be trusted to determine that St. James’ Epistula ad tribus duodecim was scripture, or that his Protoevagelium was not? And so she herself becomes not only the interpreter of scripture, but the arbiter of which writings are scripture at all. At very best, this is the beginning of Liberal Christianity, 37 which is simply shipwreck in slow-motion 38—but the puzzle even now continues to revolve, and it may at last occur to her that if the successors of the apostles who determined the canon of scripture are unreliable, so too may be the apostles who wrote the scriptures. She has now cut herself off entirely from the earthly life of Jesus, for there is no reliable means by which she can know anything about Him. The entire infrastructure of her faith has unraveled. Ironically, she is apt to feel not despair but empowerment, for she is now at last the self-actualized superwoman of Nietzche. 39 But in fact, she has thought her way out of faith, and would have done better to stick with her simple childhood faith in her friend, Jesus.

* * *

In the senses discussed, then, we may generally affirm Fischer & Hart’s notion: Although it is counterintuitive, there are senses in which doubt may be helpful to the growth of faith.


  1. Kathleen Fischer & Thomas Hart, Christian Foundations 101(1995) [Editor’s note: our principal textbook for this class].
  2. Id. (emphasis added).
  3. 1 William Thomson (1st Baron Kelvin), Electrical Units of Measurement in Popular Lectures and Addresses: Constitution of Matter 80 (1891).
  4. 1 Jn 4:12
  5. Arthur C. Clarke, 2010:Odyssey Two 189-90 (1982).
  6. N.T. Wright, Simply Christian: Why Christianity Makes Sense 24-25 (2006) [Editor’s note: an assigned text for this class].
  7. Catechism of Trent 12 (Donovan, trns., 1829); cf. Col 1:15.
  8. Fischer & Hart, supra note 1, at 18-19.
  9. Wright, supra note 6, at 24-25.
  10. See, e.g., Alex Bellos, The Grapes of Math 84-85 (2014).
  11. See, e.g., id., at 85.
  12. Charlton Lewis, An Elementary Latin Dictionary 262 (1915).
  13. Webster’s New World Dictionary of the American Language 437 (1958).
  14. American Heritage Dictionary 420 (2d ed. 1991).
  15. Webster’s New Dictionary of Synonyms 266 (1968).
  16. Oxford American Dictionary 193 (1980).
  17. Karl Rahner & Herbert Vorgrimler, Theological Dictionary 157-38 (1965).
  18. Id., at 137; cf. Matthias Premm, Dogmatic Theology for the Laity 244 (1977).
  19. Id., at 249-50.
  20. 2 Thomas Aquinas, Summa Theologica 2182 (Bezinger Bros. ed., 1945).
  21. Id., at 2182; CCC ¶¶ 644-45.
  22. CCC  ¶ 2088 (italics in original).
  23. Cf. Fischer & Hart, at 13-17.
  24. See, e.g., James Tracy, Europe’s Reformations 1450-1650: Doctrine, Politics, and Community 235-36 (2d ed. 2006).
  25. Cf. Ludwig Ott, Fundamentals of Catholic Dogma 9-10 (1954).
  26. Pius IX, Ap.Con. Ineffabilis Deus (1854), available at (last visited Sept. 17, 2014).
  27. Henri de Lubac, Paradoxes of Faith 21 (1987).
  28. Aquinas, one the greatest theologians in all history, certainly the greatest postaugustinian theologian, a Doctor of the Church, a man whose careful exegeses remain foundational and canonical texts for Christians of all denominations, lamented at the end of his life that “[a]ll I have written seems like straw.” See, e.g., Linda Edwards, A Brief Guide to Ideas 343 (2001). By contrast, the illiterate, uneducated Christians of past ages at whom Fischer & Hart sneer condescendingly, see Fischer & Hart, at 100, died in absolute certainty that they would that very day be with the Lord in paradise, cf. Lk 23:43.
  29. Cf. Jn 6:60.
  30. Harry Fosdick, The Importance of Doubting Our Doubts in What is Vital in Religion 92 (1955).
  31. Fischer & Hart, at 101.
  32. Anonymous, Against Ratzinger 85 (Shugaar, trns. 2008).
  33. 1 Pet 3:15.
  34. See Fischer & Hart, at 102.
  35. Fischer & Hart,at 99.
  36. Id.
  37. See, e.g., Eli Fay, Liberal Christianity (1889).
  38. For the long-term prognosis, see Charlotte Allen, Liberal Christianity is paying for its sins, The LosAngeles Times, July 9, 2006, (last visited Sept.12, 2014).
  39. See Fischer & Hart,at 15.