Ockham on Faith and Reason

Alfred J. Freddoso
University of Notre Dame

Analytic philosophers specializing in medieval philosophy have tended to focus on those aspects of Catholic medieval thought that seem relevant to research programs already firmly established within the mainstream of contemporary academic philosophy. In this way they have tried to convince other philosophers that the Catholic medieval thinkers, despite their theological presuppositions, have something useful to contribute to current discussions.[1] The tendency in question has been especially pronounced in the case of William of Ockham because he is at his best when doing ontology and philosophical semantics, two areas that have figured prominently in recent analytic philosophy and that seem safely removed from distinctively Catholic beliefs. 

Undeniably, much valuable reflection on Catholic medieval thought has been generated by this desire to show how certain parts of the works of Ockham and the others might bear on contemporary problematics or even inspire us to reconfigure those problematics; indeed, many academic philosophers who would not otherwise have noticed the medievals have thereby been led to treat them as full-fledged interlocuters. Still, to limit ourselves to this fragmentary approach prevents us from understanding these thinkers as they understood themselves and renders us vulnerable to the abiding temptation to refashion their work so as to make it suit our own cultural and philosophical biases. 

But how can we hope to understand the intellectual projects of the Catholic medieval thinkers as they themselves understood them? A first step in the right direction is to ask how they perceived their own relationship to the classical non-Christian philosophical traditions they had inherited. The middle ages were, of course, marked by spirited and sometimes bitter debates about how, or even whether, a given one or another of those traditions might contribute to the systematic articulation of the Catholic faith. But the question I mean to raise here is a more basic one: Did the Catholic medieval thinkers see themselves in any philosophically interesting sense as the successors of classical philosophical inquirers such as Socrates, Plato, Aristotle, and the Stoics? 

Here I will explore answers to this question gleaned from Ockham on the one hand and from his predecessors--especially Thomas Aquinas and John Duns Scotus--on the other. In so doing I will touch upon the most important general issues that have come to be lumped together under the rubric "Faith and Reason" in studies of Catholic medieval thought.[2] 

I.  Catholic tradition on the frailty of natural reason 

If the term 'successor' is taken in a suitably broad sense, then the answer to our question is unequivocally affirmative, once we grant three important assumptions that were shared by all the thinkers to be discussed here. The first is the Socratic conviction that the aim of an intellectually and morally integrated philosophical life is the attainment of wisdom--that is, the attainment of a comprehensive and systematic elaboration of the first principles of being that provides definitive answers to ultimate questions about the origins, nature, and destiny of the universe and about the good for human beings and the ways to attain it. In Aquinas's more precise formula, unqualified wisdom, which enables its possessor to "order things rightly and govern them well," consists in (1) knowledge of God as he is in himself, (2) knowledge of creatures insofar as they proceed from God as their origin, and (3) knowledge of creatures insofar as they are ordered to God as their end.[3] The second assumption is that in the pursuit of wisdom, so conceived, philosophers should draw upon all the cognitive resources available to them. The third and final assumption is that one indispensable cognitive resource is the Catholic faith itself. 

Given these assumptions, the Catholic medieval thinkers found it easy to identify Christian wisdom, personified in the incarnate Son of God and articulated systematically by Christian theology, as the real (albeit hidden) object of the quest for wisdom that the classical philosophical inquirers had initiated but had been incapable of bringing to fulfillment in the absence of Christian revelation. Indeed, this commonly shared perception of themselves as the intellectual heirs of the classical philosophers helps explain the naturalness with which the Catholic medievals carried out their interestingly diverse attempts to assimilate, or at least make use of, a wide variety of non-Christian philosophical traditions. 

As we will see in section II, agreement on this general point did not preclude an animated dispute over the precise sense in which Christian theology can claim to be the successor of classical philosophical inquiry. However, I want to pause for a moment to consider an important implication of what has been said thus far, namely, the (perhaps surprising) extent to which the Catholic faith itself deflates the pretentions of natural reason unaided by divine revelation. For it is a central Catholic doctrine that our natural cognitive powers, both theoretical and practical, are severely limited to begin with and, to make matters worse, have been gravely wounded by sin, with the result that they cannot lead us to genuine wisdom unless they are healed and elevated by the supernatural virtue of faith graciously bestowed upon us by God.[4] 

To be sure, the Catholic tradition has time and again repudiated what it considers to be insufficiently circumspect condemnations of the influence of non-Christian philosophical traditions within Christian thought. I have in mind the sort of radical intellectual separatism championed in different historical contexts by the likes of Tertullian, Eusebius of Caesarea, Martin Luther, and Karl Barth.[5] Yet it is important to see that this combative intellectual separatism, with its animus against pagan and secular philosophy and its characteristic call for a "return to Scripture," has its origins in a central Christian teaching, namely, that as long as human reason is cut off from the illumination made available through the salvific action of Jesus Christ, it cannot perceive fully or definitively the metaphysical and moral truths that constitute the object of the classical search for philosophical wisdom. Thus, although the Catholic tradition has always viewed radical intellectual separatism as a misguided exaggeration, it has nonetheless seen such separatism as the excess of a genuine virtue, to wit, an intellectual modesty that might lead even the greatest of pagan and secular philosophers to acknowlege that, as Aquinas puts it, "in divine matters natural reason is greatly deficient"[6] and to remain open, at least in principle, to the possibility of divine revelation. 

All this is necessary by way of a preface to Ockham on faith and reason. Ockham is not a radical intellectual separatist, but he is in fact less hopeful than Aquinas or even Scotus in his assessment of just how much philosophical truth natural reason is capable of acquiring without the aid of divine revelation; nor, in what follows, will I underplay the resulting differences or suggest that they are not significant. Still, I want to stress from the beginning that the differences, great as they might be, are no more impressive than the similarities. 

The reason this point is not commonly emphasized is that Scotus and especially Aquinas have often been cast as veritable rationalists in order to contrast their views on faith and reason with Ockham's alleged "fideism." To some extent this is to be expected, for historians of philosophy who follow the chronological progression from Aquinas and Scotus to Ockham have naturally tended to underscore what is distinctive to Ockham. But more recent cultural and historical factors have also engendered exaggerated estimates of the degree of confidence that Aquinas and Scotus repose in natural reason. For instance, at various times since the seventeenth century the Catholic intellectual tradition--including the Church as an institution--has deemed it necessary to defend the basic integrity of natural reason against those forms of skepticism regarding philosophical wisdom that Chesterton aptly grouped under the title "The Suicide of Thought" in his early twentieth-century apologetic work Orthodoxy.[7] Then, too, given the increasingly pluralistic character of Western liberal democracies, Catholic thinkers have felt an added pressure to find common ground with non-believers on important metaphysical and moral issues, and this has helped generate, to put it bluntly, unconscionably optimistic assessments of the power of natural reason to fashion a lingua franca that is wholly independent of specifically Christian revelation. Yet if the resulting picture is taken myopically to imply that natural reason can provide a wide range of substantive and easily discernable points of agreement between believers and non-believers regardless of other historical, cultural, and moral differences in their respective epistemic situations, then it is contrary to the positions of Aquinas and Scotus no less than to that of Ockham. In short, a good dose of wariness about the capacity of natural reason, as situated in concrete historical and cultural settings, to discern with clarity even relatively fundamental metaphysical and moral truths is and must be endemic to any authentically Catholic philosophy. 

An analogy might be useful here. Radical and universal Christian pacifism is often portrayed within mainline Catholic circles as a (perhaps dangerous) aberration in order to contrast it with what are taken to be the more reasonable requirements of classical just war theory. Yet although not entirely misleading, such a portrayal conceals the extent to which just war theory, if applied rigorously to concrete historical situations, is itself a modified pacifism that attempts to respond faithfully to the very same gospel imperatives that inspire universal pacifism. In the same way, Ockham's emphasis on the limitations of unaided human reason is often portrayed within mainline Catholic circles as a (perhaps dangerous) aberration in order to contrast it with the less gloomy assessment of natural reason associated with thinkers such as Anselm, Aquinas, Scotus, and Suarez, who constructed elaborate natural theologies and were convinced that the Catholic faith could in principle be shown to satisfy any plausible standards of rationality. Although not entirely misleading, such a portrayal obscures the firmness with which all the important Catholic medieval thinkers held to the conviction that divine revelation is absolutely necessary for us to flourish as human beings and that, as far as ultimate metaphysical and moral questions are concerned, we remain in an utterly perilous state of ignorance without it. 

By way of corroboration one need only cite Summa Contra Gentiles 1, chap. 4, where Aquinas argues in great detail that even though God's existence and many of the divine attributes can in principle be discovered by natural reason, hardly anyone, even the most astute philosophers, would have a sufficiently accurate and secure cognition of God were it not for divine revelation--and this just a few chapters before he lays out his most sophisticated rendering of the proof for an Unmoved Mover.[8] Likewise, in Summa Theologiae 1-2, ques. 94, arts. 4 and 6, he claims that although we have a sort of "connatural" cognition of the moral law, even fundamental moral precepts such as the prohibitions of theft, idolatry, and various other forms of moral corruption can be "abolished from the human heart" in fitting historical and cultural settings. Moreover, as regards moral knowledge at least, Scotus's assessment of the power of natural reason is even more bleak than Aquinas's.[9] 

With this point fixed firmly in mind, we can now move on to investigate the differences between Ockham and his predecessors. 

II.  The cognitive status of Christian theology 

As noted earlier, if the medieval Catholic thinkers concur in seeing themselves as the heirs of the classical philosophers, it is because they view Christian theology as the successor, broadly speaking, to the best of classical philosophical inquiry, both speculative (metaphysics) and practical (ethics). The disagreement between Ockham and his predecessors is most fruitfully understood as a dispute about the exact way in which this successor-relation should be spelled out.[10] 

According to Aquinas, Christian theology is a successor to classical metaphysics and ethics not merely because it replaces them or merely because it brings them to fulfillment in the sense of providing otherwise hidden answers to the questions they pose, but precisely because it perfects them according to standards of intellectual perfection that the best classical philosophers themselves subscribe to.[11] In an effort to show this clearly, Aquinas himself finally abandoned the standard theological practice of commenting on Peter Lombard's Sentences in order to reconfigure Christian theology in a systematic and non-repetitious way that was expressly intended to satisfy the criteria for a science (scientia) laid down by Aristotle in the Posterior Analytics. This effort explains the origins of the Summa Theologiae.[12] 

Ockham, for his part, denies that Christian theology can be thought of as a successor to classical philosophy in this strong sense. But in order to put his disagreement with Aquinas into proper relief, we must begin by drawing some pertinent distinctions. The first is laid out by Aquinas in Summa Contra Gentiles 1, chap. 3: 

    Among the things we profess about God there are two types of truths. There are some truths about God that altogether exceed the capability of human reason, for example, that God is [both] three and one. But there are other truths that natural reason is also capable of arriving at, for example, that God exists, that there is one God, and others of this sort. Indeed, the philosophers, led by the light of natural reason, have proved these truths about God demonstratively.
Aquinas thus divides divinely revealed truths into what he elsewhere calls the mysteries [or: articles] of the faith, which "altogether exceed the capability of human reason," and the preambles of the faith, which can at least in principle be established by the light of natural reason. Ockham draws a similar distinction between theological truths that we are naturally able to have evident cognition of and theological truths that we can have cognition of only supernaturally.[13] 

Aquinas and Ockham agree that if we are to assent to the mysteries in this life, then we must accept them on faith and thus cannot have evident cognition of them.[14] This leads us directly to the distinction between faith and other intellectual acts (or habits) with propositional objects. Aquinas defines Christian faith in its most proper sense as an intellectual act (or corresponding habit) by which a person, desirous of everlasting human fulfillment and moved by divine grace, gives firm intellectual assent voluntarily to propositions that are not evident by the light of natural reason but are taken to be revealed as truths by an unfailingly trustworthy God. Christian faith so defined is distinguished from intellectual acts like vacillation (dubitatio), tentative preference (suspicio), and probable opinion (opinio) because it involves firm assent to its objects; on the other hand, faith is distinguished from the grasp of evident first principles (intellectus) and the knowledge of conclusions seen clearly to follow from such principles (scientia) by its objects not being evident by the light of natural reason and hence not commanding 'automatic' assent but instead being freely assented to.[15] Ockham's own remarks about the supernaturally infused habit of faith fully cohere with this account.[16] 

We can now begin to appreciate the quite astonishing strength of Aquinas's claim that Christian theology counts as a science and indeed as the highest science possible for us in this life. According to Aristotle, inquiry in a given domain has as its goal wisdom with respect to that domain. Starting with an indistinct and tentative grasp of an initial set of pertinent first principles, and making full use of available logical, conceptual, and experiential resources, one conducts the inquiry by reasoning from effects back to causes, aiming ultimately to perfect one's cognitive grasp of the domain in such a way as to be able to exhibit it as a series of evident conclusions validly derived from a fully specified set of what have now become evident first principles. To have wisdom (sapientia) with respect to a domain is just to have a solid grasp of a full set of evident first principles of that domain (intellectus) along with firm knowledge of the conclusions that are seen clearly to flow from those first principles (scientia). And to have absolute or unqualified wisdom is just to have wisdom with respect to the first principles of all being; alternatively, as Aquinas and Ockham would put it, to have absolute wisdom is to have a share in God's own knowledge of himself and in God's own knowledge of all other beings insofar as they originate from him as their efficient cause and are ordered to him as their final end.[17] 

Yet, as we have seen, Aquinas not only admits but insists that in this life we can never have an evident grasp of the mysteries of the faith, which are included among the first principles of Christian theology. Rather, we must accept these mysteries on faith not only at the beginning of theological inquiry, but for as long as that inquiry continues in this life. It seems to follow straightforwardly that theological inquirers cannot have scientia with respect to the conclusions of theology. This is a point Ockham emphasizes repeatedly in his critique of the claim that "our theology" counts as a science: 

    An [intellectual] habit with respect to the principles is better known and more evident than [the corresponding] habit with respect to the conclusions; therefore, it is impossible for the principles to be taken merely on faith and the conclusions to be known scientifically (Ordinatio I, prologue, q. 7, OTh 1, p. 189, lines 18-20).
As Ockham well realizes, Aquinas has a reply to this objection.[18] An evident grasp of the first principles of theology is, to be sure, had only by God himself and by the blessed in heaven, who see God face-to-face and participate to greater and lesser degrees in the "light of glory." Still, one science can be subordinated to a second and higher science in the sense that it includes among its own first principles propositions that are evident only to one who possesses that second science--in the way, for instance, that physicists and chemists take for granted various conclusions of the mathematical sciences. Similarly, Christian theology is a subordinate or subalternate science that includes among its first principles certain propositions--namely, the mysteries of the faith--that are evident only to those who have perfect absolute wisdom, namely, God and the blessed in heaven. And just as it is reasonable to credit physicists and chemists with scientific knowledge of their domains even when they do not have an evident grasp of all the mathematical conclusions they make use of, so too theological inquirers can be credited with scientific knowledge about God and creatures even though they do not have an evident grasp of the mysteries of the faith. Thus, Aquinas concludes, Christian theology augments the first principles available to the classical philosophers with certain propositions which, though they can be grasped evidently only by God and the blessed in heaven, must be firmly assented to by anyone who wishes to attain the highest science, and thus the highest degree of absolute wisdom, possible for us in this life. 

To this line of thought Ockham has an unceremonious reply. He is simply unwilling to back away from the strict definition of what it is for someone to have scientific knowledge of a conclusion: 

    As for the claim that there are two kinds of science, one of which proceeds from principles that are known per se by the light of a higher science, I reply that even though this is true of a subordinate science, still, no given individual ever has evident knowledge of the relevant conclusions unless he knows them either through experience or through premises that he has evident cognition of. Hence, it is absurd to claim that I have scientific knowledge with respect to this or that conclusion by reason of the fact that you know principles which I accept on faith because you tell them to me. And, in the same way, it is silly to claim that I have scientific knowledge of the conclusions of theology by reason of the fact that God knows principles which I accept on faith because he reveals them (Ordinatio I, prologue, q. 7, OTh 1, p. 199, lines 10-18).
Once again, though, Aquinas has the resources for an interesting counterargument. Classical philosophical inquirers had aimed for a certitude that perfects the human intellect both in its theoretical function of grasping ultimate metaphysical and moral truths and in its practical function of making good deliberations, judgments, and precepts of action whose purpose is to guide the philosophical wayfarer successfully through day-to-day living. But, says Aquinas, there are two distinct types of certitude, one associated with faith and the other with the natural intellectual virtues of intellectus (evident grasp of first principles), scientia (evident knowledge of conclusions derived from those principles), and sapientia (wisdom that combines intellectus and scientia so defined): 
    Certitude can be thought of in two ways. First, in terms of the cause of certitude and, accordingly, that which has a more certain cause is said to be more certain. And in this sense faith is more certain than the three intellectual virtues mentioned above [intellectus, scientia, and sapientia], since faith is founded on divine truth, whereas those three virtues are founded on human reason. In a second way, certitude is thought of in terms of the subject and, accordingly, that which the human intellect preceives more fully is said to be more certain; and because the things that belong to faith, but not the things that belong to the three virtues in question, lie beyond human understanding, faith is less certain in this sense. Yet since each thing is judged absolutely according to its cause, ..... it follows that faith is more certain absolutely speaking (Summa Theologiae 2-2, ques. 4, art.8).
Thus, even though it is true that the natural intellectual virtues in their perfected states exceed faith in the degree of evidentness with which one who has them grasps their objects, it is equally true, Aquinas asserts, that Christian faith in its perfected state exceeds the natural intellectual virtues in the degree of firmness with which one who has it adheres to divinely revealed truth--even to the point of voluntarily undergoing martyrdom in order to give witness to that truth. 

Here we glimpse unmistakably the wariness about natural reason that characterizes Aquinas no less than Ockham. In other places Aquinas cites approvingly Aristotle's dictum that natural reason is as incapable of comprehending the most intelligible natures as the eye of an owl is of viewing the sun.[19] Even though the mysteries of the faith are not evident to us by the light of natural reason, they are nonetheless more certain for the devout and prayerful believer than are even the simplest self-evident truths. For God himself, who by his grace enables us to recognize certain non-evident propositions as divinely revealed truths and empowers us to adhere to those truths by the gift of faith, is a more reliable source of true cognition than is the relatively dim light of natural reason. In short, our grasp of the first principles of theology by faith is firmer and more certain than any grasp of first principles we might have by the faint light of natural reason, and our consequent grasp of the conclusions validly derived from those principles will share in the certitude we have with respect to the first principles and will thus be more certain, absolutely speaking, than our grasp of the conclusions of any merely human science. If, therefore, like the classical philosophical inquirers, we have as our goal certitude with respect to a full set of ultimate metaphysical and moral truths, then Christian theology, by including the mysteries of the faith among its first principles and by exemplifying the highest available degree of certitude in both its first principles and its conclusions, brings classical philosophical inquiry to perfection and provides us with the surest and most comprehensive philosophical wisdom possible for us in this life. Consequently, it is wholly appropriate to extend to "our theology" the honorific status of a science; it is, after all, a "super-science" that exceeds every human claim to absolute wisdom according to the very same standards--namely, completeness and certitude--appealed to by the classical philosophical inquirers themselves. 

In response, Ockham begins by conceding that "the Saints all call [theology] a science by extending the term 'science' to the certain cognition ..... of [propositions] that are of themselves fit to be the objects of science and wisdom [in the strict sense]."[20] Yet he resolutely insists that the strict Aristotelian standard of evidentness must govern any proper application of the terms 'intellectus', 'scientia', and 'sapientia'. And by this standard, Ockham charges, Aquinas is inconsistent in denying that Christian inquirers have intellectus with respect to the principles of theology, which they firmly adhere to without evidentness, while at the same time affirming that they have scientia--which by Ockham's lights can only mean evident knowledge--with respect to the conclusions of theology: 

    It does not detract from the dignity of our theology that its conclusions are not known with evidentness--just as it does not detract from the dignity of our cognition of the principles of theology that they are not known with evidentness. And so just as there is no derogation involved in the fact that the principles are not known evidently, so too with the conclusions. And when it is claimed that [our theology] exceeds other [sciences] both in the dignity of its subject matter and in certitude, I reply that this argument proves equally well that the principles [of our theology] are known with evidentness; for those principles exceed the others both in certitude (since they are not subject to human reason) and in the dignity of their subject matter just as well as the conclusions do. Therefore, I claim that 'certitude' is being taken either for adherence or for evidentness. In the first sense, they do exceed [the conclusions of the other sciences], but not in the second sense (Ordinatio I, prologue, q. 7, OTh 1, p. 199, line 19 - p. 200, line 8 ).

III.  Substantive or merely verbal disagreement? 

At this juncture it might appear that the dispute between Ockham and Aquinas is merely verbal. And to some extent this is surely true. After all, both agree that neither our grasp of the first principles of theology nor our logically subsequent cognition of the conclusions of theology strictly satisfies the definitions of 'intellectus' and 'scientia' laid down by Aristotle because  those definitions include the stipulation that the objects of these cognitive virtues are evident by the light of natural reason. Further, they agree that theology has, in Ockham's words, "the role of standing in judgment on the other arts because of a greater truth in the things that are cognized and because of a firmer adherence [to them]."[21] For even though the mysteries of the faith are, like the sun, too bright for us to take in directly, they nonetheless illuminate all other things much more brightly than do the deliverances of natural reason. Again, Ockham and Aquinas agree that theological sophistication is not necessary for salvation, and that all devout believers, even the theologically unsophisticated, have divinely infused "gifts of the Holy Spirit," habits by which they are able--through supernatural instinct, as it were, rather than through reasoned cognition--(i) to distinguish genuinely revealed doctrines from counterfeits, (ii) to view created things in the supernatural light of faith, and (iii) to know more intimately the Divine Persons to whom they are joined in the friendship of supernatural charity.[22] Finally, Ockham and Aquinas agree that the systematic study of theology engenders in theological inquirers various intellectual acts and habits that distinguish them from those theologically unsophisticated believers who are ill-equipped to engage in the properly theological activity of articulating and defending Christian doctrine. Yet, although Aquinas confers the honorific title 'science' on this set of intellectual acts and habits, Ockham steadfastly demurs: 

    From the distinction between the acts [proper to faith and those proper to theology] it cannot be proved that theology is a science. For every [properly theological] act that a believer has can be had by a non-believer who is trained in theology. After all, such a non-believer could defend and confirm the faith, persuade believers and non-believers, and reply to the arguments of heretics and non-believers in just the way that any believer could. And yet it is obvious that such a non-believer would not have scientia properly speaking. Therefore, from such acts it cannot be proved that theology is a science properly speaking (Ordinatio I, prologue, q. 7, OTh 1, p. 190, lines 16-22).
One could, of course, accept the entire antecedent of this argument and still reject the consequent, noting that it is hardly implausible to restrict the terms 'scientia' and 'sapientia' to those who actually assent to the first principles from which the conclusions of theology are derived. But, once again, this terminological point does nothing to dispel the impression that on the issues we have been discussing there is no substantive disagreement between Aquinas and Ockham.[23] 

Nevertheless, if we situate the dispute over the cognitive status of theology within the broader context that renders it fully intelligible, we will indeed discover a substantive disagreement. We must begin by fleshing out more explicitly Aquinas's claim that Christian theology perfects classical metaphysics and ethics according to standards of intellectual perfection that the best classical philosophers themselves subscribe to. Once we see clearly the far-reaching implications of this claim, we will be in a better position to understand just why Ockham rejects it. 

What Aquinas is suggesting is that those classical philosophical inquirers who are morally and intellectually well-disposed could be led, by standards they themselves have adopted, toward recognizing Christian theology as a plausible candidate for the absolute wisdom they are seeking. This is not to say, however, that such recognition would come immediately or easily; rather, if it came at all, it would likely emerge in three stages, each of which presents a daunting challenge to the Christian apologist. 

In the first stage the Christian apologist would try to convince the best classical philosophers that certain first principles of Christian theology--namely, the preambles of the faith--are either conclusions that they themselves have already arrived at by their own standards of successful philosophical inquiry or conclusions that they would have arrived at had they done better by those very same standards. This is precisely the apologetic task that Aquinas undertakes in the first three books of the Summa Contra Gentiles and that Anselm and Scotus undertake in their own natural theologies. 

Now suppose that the Christian apologist accomplishes this first task and in so doing removes one set of intellectual obstacles that might prevent classical philosophical inquirers from seeing Christian theology as a serious candidate for absolute wisdom. At this point the classical philosophers will likely express the worry that even if one part of Christian doctrine can be established by their own standards, there are other elements--including doctrines about the Trinity, the Incarnation, the Atonement, the Sacraments, and so on--that not only cannot be so established but also have every appearance of directly contravening those standards. At this second stage, then, the Christian apologist, who concedes that the mysteries of the faith cannot be proved by the light of natural reason, has the task of showing that neither can they be shown to be false or impossible by the light of natural reason. This is precisely the task that Aquinas undertakes in book four of the Summa Contra Gentiles, and the result of which Scotus (as summarized by Ockham) characterizes as follows:[24] 

    With respect to any [truth] of [Christian] theology it can be known scientifically that nothing impossible follows from it, since either (i) there will be a flaw in the form [of the relevant argument], in which case the argument can be refuted, or else (ii) there will be a flaw in the matter [of the argument], in which case [the relevant premise] can be rejected (Ordinatio I, prologue, q. 7, OTh 1, p. 186, lines 8-13).
Assume, once again, that the Christian apologist has accomplished this task and in so doing has removed a second set of intellectual obstacles that might prevent the classical philosophers from acknowledging Christian theology as the culmination of their own search for absolute wisdom. Obviously, not just any claim to absolute wisdom will have survived this far and been shown to be consonant with the classical standards of successful intellectual inquiry as measured by the light of natural reason. Indeed, one can plausibly imagine that well-disposed classical inquirers, especially those who have a just sense of the limitations of human reason, might by this point have adopted a cautious openness toward Christian revelation that was not present at the beginning of their dialogue with the Christian apologist. Recall Aristotle's comparison of the light of reason to the eye of an owl, and consider the words that Plato puts into the mouth of Simmias during an interlude in the debate over immortality in the Phaedo
    I think, Socrates, as perhaps you do yourself, that it is either impossible or very difficult to acquire clear knowledge about these matters in this life. And yet he is a weakling who does not test in every way what is said about them and persevere until he is worn out by studying them on every side. For he must do one of two things; either he must learn or discover the truth about these matters, or if that is impossible, he must take whatever human doctrine is best and hardest to disprove and, embarking upon it as upon a raft, sail upon it through life in the midst of dangers, unless he can sail upon some stronger vessel, some divine revelation, and make his voyage more safely and securely" (Phaedo, 85c-d, translated by Howard North Fowler).
The third stage of the Christian apologist's task consists in pointing out that because some elements of Christian theology have been proved by the light of natural reason (first stage) and all of them have been shown not to be contrary to reason (second stage), the classical philosophical inquirers can now see by their own standards that those who assent to Christian revelation are, from within the framework of faith, entitled to think of Christian theology, which articulates that revelation systematically, as the perfection of classical philosophical inquiry. After all, given the admission that natural reason cannot take us all the way to our preferred destination of certitude with respect to a full set of ultimate metaphysical and moral truths, the classical philosophical inquirers would be foolish by their own standards if they curtly dismissed any claim to divine revelation that passes the first two tests and promises certitude with respect to matters that all sides admit to be crucial for living the sort of life worthy of a human being. 

The Christian apologist would presumably go on from this point to produce, as Aquinas does in Summa Contra Gentiles 1, chap. 7, various further indications of the reliability of the specifically Christian claim to divine revelation over other such claims. However, we have already said enough to establish a context that renders intelligible and perhaps even plausible the Thomistic and Scotistic claim that Christian theology is a science that perfects classical philosophical inquiry. 

Yet given this same context, we can now understand more easily why Ockham balks at the suggestion that Christian theology is a science and why he insists on adhering to the strict senses of terms such as 'intellectus', 'scientia', and 'sapientia'. The reason is simple and straightfoward: he is convinced that the first two stages of the Christian apologist's task, as described in the preceding paragraphs, are doomed to failure. But if this is so, then it is utterly pointless to claim that Christian theology is something more than a mere replacement for classical philosophical inquiry. Why, after all, would Christian intellectuals even bother to press such a claim? Whom would they be trying to impress? If little or none of Christian doctrine can be established by natural reason, and if much of what is peculiarly Christian cannot even be shown not to be contrary to the light of natural reason, then no classical philosophical inquirer, no matter how well-disposed, would be so much as tempted to accord any special intellectual merit to the acceptance of Christian revelation. 

I will now expound a bit more on Ockham's attitude toward natural theology and on his contention that the mysteries of the faith cannot be shown to be consonant with natural reason. 

IV.  Natural theology 

As a Catholic thinker of the late thirteenth and early fourteenth centuries, Ockham inherited from Anselm, Aquinas, and Scotus three magnificent, yet quite dissimilar, attempts to establish by the light of natural reason the existence of a being with an array of positive and negative perfections that Christian revelation attributes to the divine nature. 

Anselm had formulated a two-step natural theology, consisting of (1) an ingenious a priori argument that, if successful, immediately yields the existence of an absolutely perfect being, and (2) a systematic deduction and explanation of various attributes such a being must have. 

Aquinas, rejecting Anselm's a priori argument along with the assumption that we begin with a concept of God on a par with our simple natural-kind concepts of material entities, had constructed a three-step natural theology, consisting of (1) an a posteriori argument for the existence of a first efficient cause or unmoved mover, that is, a being that acts but is not itself caused or acted upon; (2) the via remotionis, in which he argues that a first efficient cause lacks various limitations characteristic of entities that we do have simple natural-kind concepts of, with the result that a first efficient cause must be an absolutely perfect being; and (3) the via affirmationis, in which he argues that severasl pure positive perfections, suitably abstracted from the restrictive conditions under which they occur in other entities, are to be attributed literally, though analogically, to this perfect being.[25] 

Scotus's natural theology, in certain respects the most impressive of all, consists of three main stages: (1) a three-pronged proof for (a) the existence of an entity with the relational property of being first in the order of efficient causality, (b) the existence of an entity with the relational property of being first in the order of final causality, and (c) the existence of an entity with the relational property of being first in the order of perfection; (2) an argument showing that exactly one being has all three of these preeminent relational properties; and (3) a series of arguments showing that the possessor of this "triple primacy" is an infinite being with intensively infinite power, knowledge, goodness, and overall perfection.[26] 

Ockham, by contrast, is decidedly less sanguine than his predecessors concerning what natural reason, unaided by divine revelation, can demonstrate about the existence and nature of God. It is demonstrable, he believes, that there is a being such that no being is prior to or more perfect than it, but it is not demonstrable that there is just one such being.[27] Moreover, even though there are 'probable'--that is, not implausible--philosophical arguments for the conclusion that one or another infinite absolute perfection is actually possessed by some being,[28] unaided reason cannot demonstrate that any being has any such perfection. 

Like many another medieval thinker, Ockham tries his hand at refuting Anselm's a priori argument for the existence of an absolutely perfect being.[29] However, he focuses his attention mainly on Scotus, arguing in effect that each of the three stages of Scotus's natural theology is flawed. In particular, he contends that (i) natural reason cannot prove the existence of a being that has any one of the three types of primacy Scotus argues for, that (ii) even if natural reason could prove the existence of a being with one or another of these types of primacy, it would still be unable to prove that just one being has all three of them, and that (iii) even if natural reason could prove that there is just one being with all three types of primacy, it would still be unable to prove that this being has any intensively infinite perfections.[30] Without spelling out in detail the many objections that Ockham levels at Scotus's arguments, I will note only that these objections are of uneven quality. Some are quite ingenious and worthy of serious consideration, whereas others amount to little more than the unadorned assertion that a given proposition or inference cannot be proved by natural reason or that it would be rejected by a non-believing philosopher. 

However, the most important difference between Ockham and his predecessors is more subtle than any standard philosophical disagreement over a particular premise or inference. In perusing the objections that Aquinas and Scotus raise against Anselm's natural theology or that Scotus raises against Aquinas's natural theology, the reader has the sense that the later thinkers take themselves to be collaborators with their predecessors in the shared project of exhibiting the intellectual merits of Christian doctrine from the perspective of natural reason. Their intent is always either to rectify arguments they see as defective or to suggest alternative ways of proceeding. Moreover, they view their common project both as perfective of the thinkers who engage in it and as useful for carrying on a potentially fruitful conversation with those non-believing yet morally and intellectually well-disposed classical philosophers with whom they feel a special kinship. By contrast, Ockham's discussions of natural theology give the clear impression that he has no interest at all in repairing the arguments he finds defective or in trying to reveal new intellectual horizons to the non-believing philosophers he so often invokes as witnesses against his predecessors. And even though this negative attitude is undoubtedly as much a symptom as a cause of Ockham's misgivings about Scotus's arguments, it often permeates his discussions of natural theology to such an extent as to give them the appearance of being mere technical exercises. 

V.  Conflicts between faith and reason 

Yet even though the disagreements over natural theology are significant, the deepest split between Ockham and his predecessors is reflected in their differing attitudes toward the epistemic tensions generated by certain mysteries of the faith, especially the doctrines of the Trinity and the Incarnation. 

I will focus here on Ockham's discussions of the Trinity. According to this doctrine, a unitary divine nature with undivided intellect and will is shared by three distinct divine persons. A tension first arises in Ockham's thought when, after having argued in favor of what he takes to be Aristotle's contention that there are no real relations and hence that relative terms do not signify entities distinct from absolute entities, he concedes that the doctrine of the Trinity entails or at least strongly suggests that the three divine persons are constituted by real relations of knowing and loving that they bear to one another.[31] 

Given this apparent conflict between faith and reason, Aquinas and Scotus would maintain that the ontological theory (call it T) leading to the strong conclusion that there are and can be no real relations contains a flaw that may at least in principle be detected and rectified by the light of natural reason. In a case like this, revelation guides reason by prompting the reexamination of a philosophical theory that it has exposed as unsound.[32] 

Ockham, however, does not see things this way. To be sure, T contains a flaw, because it yields the false conclusion that there are and can be no real relations. But it is only through revelation that we can so much as detect T's falsity, and so we should not expect the flaw in T to be one that can be corrected by the light of natural reason. Indeed, the presence of this sort of flaw in T does nothing to alter its status as the best account of the signification of relative terms that can be formulated by unaided natural reason. Thus, although we must reject T, the proper course is to accept a restricted version of T (call it T*) that applies to all and only those cases about which revelation has nothing contrary to say--even while we admit that T has no flaw detectable by natural reason and hence that by the light of natural reason there is no warrant for preferring T* to T

To make this a bit clearer, suppose that a non-Christian philosopher invokes T to pose an objection to the doctrine of the Trinity. This philosopher argues that because, according to T, there are and can be no real relations, the doctrine of the Trinity is false. 

As we have seen, Aquinas and Scotus will maintain in response that T can be correctly impugned and rejected by the light of natural reason alone. For, they will argue, natural reason is a gift from God, who cannot be the direct source of error and hence could not create us with cognitive faculties that systematically mislead us regardless of how carefully or skillfully we use them and regardless of the conditions under which we carry out our inquiries. It follows that T is not so highly warranted by the light of natural reason as to rule out its competitors as unacceptable by that same light. Christian thinkers are thus charged with the task carrying out a careful critique of T by the light of natural reason and constructing an alternative to it. In general, they will try to show (1) that doctrine of the Trinity, whether or not it generates exceptions to otherwise general truths, cannot be shown to be unacceptable by the light of natural reason, and thus that (2) an adequate ontological account of relations will have within itself the conceptual resources to accommodate this doctrine, as well as any exceptions it might engender, without inconsistency or incoherence. To be sure, there is no guarantee that any particular attempt to carry out this task will be successful, but there is a guarantee that success is at least in principle possible. 

Ockham, by contrast, seems fully prepared to hold that T, despite entailing conclusions contrary to the faith, is indeed warranted to such a degree that it renders its ontological competitors unacceptable by the light of natural reason. His response to the non-believing philosopher goes like this: "I affirm by faith that T is mistaken, even though you and I share no common ground upon which I can argue my case against T in a way that has some purchase on you. But because T is the only rationally acceptable account of relations, I do not propose to jettison it entirely. Instead, I will substitute T* for T, so that we can agree at least on all those cases that divine revelation does not speak to. You might find this response deficient and even a bit annoying, because I have not tried to refute your objection directly. But in this instance such a refutation is impossible." 

In short, Ockham seems clearly to countenance the possibility of conflicts between faith and reason that are in principle irresoluble. As he sees it, certain mysteries of the faith are not just beyond natural reason, but contrary to natural reason. And, once again, it is easy to understand why someone who holds this view would not be inclined to value very highly--or, a fortiori, engage in--the sort of apologetic outreach to philosophically sophisticated non-Christians that Aquinas and Scotus take as an integral part of the task of Christian intellectuals. 

VI.  Conclusion: Ockham's irenic separatism  

Ockham is not a radical intellectual separatist who disdains natural reason or regards with suspicion any Christian thinker who wishes to study the works of non-Christian philosophers with the same intensity as the books of Sacred Scripture. In fact, anyone familiar with Ockham's thought knows that he has immense respect for Aristotle and that his theology is marked by (what he believes to be) Aristotelian positions on a wide range of issues in ontology and philosophical semantics.[33] 

Yet, as we have seen, Ockham rejects the notion that intellectual inquiry as practiced by the classical non-Christian philosophers, even Aristotle himself, is a useful propaedeutic to the Christian faith. Natural reason is sufficiently powerful and trustworthy when it operates within its proper sphere, but it is too weak to provide much illumination in the arena of natural theology and it is downright unreliable when used to pass judgment on the first principles of revealed theology. To be sure, philosophical inquiry unaided by divine revelation can help foster logical skills and intellectual habits that are required for the articulation of true wisdom within Christian theology; it can even provide Christian thinkers with new and useful conceptual resources. But it cannot on its own make any noteworthy progess toward providing us with the substance of absolute wisdom. 

Therefore Ockham's is an irenic separatism that rejects the prototypically Catholic intellectual project of unifying classical philosophy and the Christian faith in such a way as to exhibit the latter as the perfection of the former, and yet that stops short of disdaining the light of natural reason in the manner of radical intellectual separatism. Perhaps this explains why, on the matters we have been discussing here, Ockham will always be viewed as something of an outsider both by the radical separatist, who is bent on isolating faith and reason completely from one another, and by the mainstream Catholic thinker, who seeks a genuine synthesis of faith and reason. 


1. The most salient piece of evidence for this claim is found in the table of contents and introduction of Norman Kretzmann, Anthony Kenny and Jan Pinborg, eds., The Cambridge History of Later Medieval Philosophy (New York: Cambridge University Press, 1982). 

2. All volume, page, and line references to Ockham's writings are from the nine-volume critical edition of his theological works: Guillelmi de Ockham, Opera Theologica (hereafter: OTh) (St. Bonaventure, NY: Franciscan University Press, 1967-1980). 

3. Summa Contra Gentiles 1, chaps. 1 and 9. 

4. See, e.g., Summa Theologiae 1-2, ques. 85 on the effects of sin, both original sin and personal sin. 

5. For an excellent discussion of the relevant theological and philosophical issues, see John Courtney Murray, The Problem of God (New Haven, CT: Yale University Press, 1964), chap. 2. 

6. Summa Theologiae 2-2, ques. 2, art. 4. See also Summa Contra Gentiles 1, chap. 2. 

7. G.K. Chesterton, Orthodoxy (San Francisco, CA: Ignatius Press, 1908, 1995), chapter 3. Chesterton is uncannily prescient in his delineation of the conceptual rhythm of post-modern skeptical movements, especially pragmatism and Nietzscheanism. 

8. Surprisingly, even though almost every anthology designed for use in introductory college courses in philosophy either contains or alludes to Aquinas's arguments for God's existence, hardly any of them (I know of only one) sets the context for those arguments by reprinting Summa Contra Gentiles 1, chap. 4 or Summa Theologiae 2-2, ques. 2, art. 4. 

9. A closely reasoned argument for this claim can be found in W. Thomas Williams, The Moral Philosophy of John Duns Scotus (University of Notre Dame Ph.D. Dissertation, 1994), esp. chap. 5. 

10. I will concentrate here mainly on Aquinas's argument for the claim that Christian theology is a science, since his discussion is somewhat richer and more easily available than Scotus's. However, Scotus holds basically the same position and Ockham's arguments are directed against him as well as against Aquinas. I wish to acknowledge here a debt of gratitude to my colleague John Jenkins, CSC, whose recent book Knowledge and Faith in Thomas Aquinas (Cambridge: Cambridge Univ Press, 1997) has helped me appreciate the centrality of the medieval discussion of whether Christian theology is a science and has shaped my reflections on that question. 

11. This is the thrust of the first seven articles of the Summa Theologiae, which should be read in conjunction with the first nine chapters of the Summa Contra Gentiles. In similar fashion, Ockham takes up these questions at the very beginning of his commentary on Peter Lombard's Sentences; see Ordinatio 1, prologue, esp. ques. 7 (OTh 1, pp. 183-206). 

12. In the prologue to the Summa Theologiae Aquinas explains: "We have taken into consideration the fact that newcomers to this study are commonly hampered by the writings of different authors--(i) partly because of the proliferation of superfluous questions, articles, and arguments, (ii) partly because the things they need to know are taught not according to the order of learning, but instead as is required by the exposition of given texts or as opportunities arise for disputing given questions, and (iii) partly because frequent repetition has generated both antipathy and confusion in the minds of the listeners. In an effort to avoid these and other such problems, we will try, with trust in God's help, to set forth what pertains to sacred doctrine as briefly and clearly as the subject matter allows." 

13. See Ordinatio I, prologue, q. 1, OTh 1, p. 7, lines 11-15. 

14. This claim stands in need of a minor qualification, since according to Ockham there are some mysteries of the faith that we could--though only miraculously--have evident cognition of in this life without having attained the beatific vision. See Ordinatio I, prologue, q. 1, art. 5 (OTh 1, p. 49, line 10 - p. 51, line 24), and Quodlibeta Septem V, ques. 4 (OTh 9, pp. 491-495). However, this qualification does not figure in what follows. 

15. See Summa Theologiae 2-2, ques. 2, art. 1 and De Veritate, ques.14, art. 1. 

16. See, for instance, Quodlibeta Septem III, ques. 7-8, (OTh 9, pp. 228-237) and Quodlibeta Septem IV, ques. 6, (OTh 9, pp. 322-327). 

17. For an especially penetrating account of inquiry according to the Aristotelian model, see Alisdair MacIntyre, First Principles, Final Ends and Contemporary Philosophical Issues (Milwaukee, WI: Marquette University Press, 1990), sections III-IV. Notice that there is a systematic ambiguity between (i) science (or better: wisdom) conceived of as an abstract propositional structure that is capable of being grasped by an intellect and (ii) science conceived of as an ordered set of psychological acts or habits that are present in an intellect. Below I will not always take the time to translate claims made in one of these modes into the other mode. However, this should engender no confusion, since the relevant translations are easy enough to make. 

18. What follows is a reconstruction of remarks Aquinas makes in Summa Theologiae 1, ques. 1, arts. 2, 5, and 6. 

19. See, for example, Summa Theologiae 1, ques. 1, art. 5, ad 1. 

20. Ordinatio I, prologue, q. 7 (OTh 1, p. 200, lines 12-15). 

21. Ordinatio I, prologue, q. 7 (OTh 1, p. 200, lines 10-11). Aquinas makes precisely the same point in Summa Theologiae 1, ques. 1, art. 6, ad 2. 

22. The three functions mentioned here are assigned, respectively, to the gifts of intellectus, scientia, and sapientia, which are similar to the homonymous intellectual virtues in their functions but dissimilar in their mode of operation. Aquinas characterizes this dissimilarity as a difference between judging by way of inclination and judging by way of cognition. (See Summa Theologiae 1, ques. 1, art. 6 and Summa Theologiae 2-2, ques. 45, art. 2.) Consider the following analogy: One who has acquired the virtue of temperance will judge by way of inclination--that is, instinctively or by second nature--that a certain concrete situation calls for restraint and will act accordingly even without having thought deeply about moral theory; by contrast, a moral theorist who lacks temperance might make the very same judgment by way of cognition even though lacking the capacity to act promptly on that judgment. The same, says St. Thomas, holds for Christian wisdom. All devout Christians possess the gift of wisdom, which enables them to judge things correctly by way of inclination and to act promptly on those judgments; this is the wisdom that accompanies the supernatural love of God and is especially well-developed in those who lead saintly lives. On the other hand, those versed in theology or sacred doctrine acquire through study the ability to make wise judgments about divine things by way of cognition. As with temperance, it is better, all other things being equal, to have wisdom in both ways than to have it in just one; but given that one has it in only one way, it is better to be wise by way of inclination than merely by way of cognition. 

23. Aquinas would undoubtedly question Ockham's assertion that every theological act had by a believer could be had by a non-believer trained in theology. For, he would claim, certain theological acts can be had only by one who combines intellectual brilliance, the infused gifts of the Holy Spirit, and a deep sanctity nurtured by prayer and the sacraments. However, this issue is too complicated to pursue here. 

24. Compare Aquinas, Summa Contra Gentiles 1, chap. 7. 

25. This triadic structure is clearly evident in Summa Contra Gentiles I, chaps. 10-102. 

26. See Opus Oxoniense I, dist. 3, ques. 1-2. An English translation is available in Duns Scotus, Philosophical Writings: A Selection, trans. by Alan Wolter (Indianapolis, IN: Hackett Publishing Co., 1987). 

27. See Quodlibeta Septem I, ques. 1, (OTh 9, pp. 1-11), where Ockham argues for the existence of a being that is unsurpassed in perfection. The Quodlibeta Septem is found in English translation in William of Ockham, Quodlibetal Questions, Volume 1: Quodlibets 1-4, trans. by Alfred J. Freddoso and Francis E. Kelley (New Haven, CT: Yale University Press, 1991), and Quodlibetal Questions, Volume 2: Quodlibets 5-7, trans. by Alfred J. Freddoso (New Haven, CT: Yale University Press, 1991). 

28. See, for instance, Quodlibeta Septem VII, ques. 18 (OTh 9, pp. 774-779), where Ockham lays out and defends an interesting argument for God's omnipotence. 

29. See Quodlibeta Septem VII, ques. 15 (OTh 9, esp. pp. 759-761). 

30. The following questions of the Quodlibeta Septem contain Ockham's most mature thought on these issues: Quodlibeta Septem I, ques. 1 (OTh 9, pp. 1-11).; II, ques. 1 (OTh 9, pp. 107-111); III, ques. 1 (OTh 9, pp. 199-208); IV, ques. 1-2 (OTh 9, pp. 293-309); and VII, ques. 11-18 (OTh 9, pp. 738-779). 

31. "This fourth opinion, [namely, that the divine persons are constituted by absolute properties and not by real relations] could seem plausible to someone. Nonetheless, since the citations from the Saints seem expressly to posit relations in the divine nature--not just in the sense that certain relative concepts are truly predicated of the divine persons, as when we say that Socrates is similar and that Socrates is a father or a son, but rather in the sense that in the divine nature there exists a real paternity and a real filiation and that these are two simple entities neither of which is the other--I affirm in agreement with them that the divine persons are constituted and distinguished by relations of origin" (Ordinatio I, dist. 26, ques. 1 (OTh 4, p. 156, line 23 - p. 157, line 7). 

32. I am assuming that in the present context there is no question about what the relevant theological doctrine entails. But this need not always be the case according to Aquinas and Scotus. For they believe that reason can legitimately constrain the interpretation of the sources of revelation, so that apparent conflicts between philosophical or scientific theories and articles of the faith may in some instances call for careful analysis of doctrinal statements as well as of arguments yielded by the light of natural reason. 

33. He is not so taken with Plato and neo-Platonism, but that is a tale for another time.