I've previously sketched an account of fundamental theology as an answer to modernism and nihilism, I want to point out how this fundamental theology responds to presuppositionalism, one of the rival Christian philosophies that emerges from the challenges of modernity. Based on the beliefs entailed in the fundamental theology that Jesus is God, I conclude that presuppositionalism does not work as a Christian epistemology.
I. Fundamental Theology as a Discipline
Recall that fundamental theology as I have outlined it is (1) a response to modernity (and its inevitable nihilism) based on (2) a coherent account of the fundamental Christian belief that Jesus is God. The approach is based on an acknowledgement of the limits of formal systems based on the work of Gödel, Tarski, Quine, and Kuhn, as well as similar conclusions in physical science demonstrated by the theory of general relativity and the uncertainty principle of quantum mechanics. It serves as a response to the Enlightenment skepticism of reason exemplified by David Hume and Immanuel Kant, and it can, properly speaking, be called a postmodern approach to fundamental theology as John Deely defines it. It cannot be characterized as postmodernism, the denial of meaning itself, but rather as a critical (metaphysical) realist method of inquiry intended to provide abductive explanations of our experiences centered around the kerygma that Jesus is God. To put it another way, it is a way of doing theology as science, not in the classical Aristotelian sense, but in analogy to how contemporary scientific inquiry is practiced. But what is being explained is a set of dogmatic facts -- moments, events, and statements given normative status by the Christian churches over time that articulate the central revelatory event of the Incarnation.
There are, to be sure, those Christians who want to deny that the questions of the Enlightenment have any legitimacy at all. That is not the call of fundamental theology but fundamentalism, the return to the time where no one cast explicit doubts on the certainty of reason. The problem is that this time never really existed. The questions raised by the Enlightenment had already started to arise even within scholastic Catholicism. As Jose Pereira points out in his article "John of St. Thomas and Suárez," "For Suárez the basic principles of Thomism are, at best, open to debate and are unnecessary to found a metaphysics, a fact that makes the system, when not fallacious, superfluous. The rationale of Suárez’s critique of classical Thomism is that it tends to reify concepts." And as John Deely points out in Augustine and Poinsot, questions about the metaphysical nature of signs had already been asked by Augustine and had been given an extended analysis by the same John (Poinsot) of St. Thomas who is discussed in Pereira's article. Accordingly, this idea that we need to return to some epistemologically unsophisticated Eden where people gave no thought to the source of their knowledge is chimerical. What we need to understand is not the ability of older theologians to address these questions, which they certainly had resources to do when they were inclined to do so, but why they cared so little about them.
The lesson that we should take from that indifference is not that questions of epistemology raised by the Enlightenment are idle or unimportant; they are not. What we instead must consider is why they took on such a disproportionate level of importance in the Enlightenment, and that relates back to the issues I raised in my blog article Calvinism: A Dead End Theory. In that article, I noted that Ockham's nominalism, which was enormously influential for modernity and the Enlightenment, reduced explanations to super-voluntarism, the exclusive use of the inscrutable divine will as a metaphysical explanation. This inevitably results in a zero-sum game between the divine and human wills that ultimately does not allow for an adequate account of God as Creator. The best evidence that this is the case is that an analogous denial of natures by al-Ghazali led to the same outcome in Ash'arism, even though it took place in the context of a completely different monotheistic religion.
The flip side of super-voluntarism is that epistemology, now severed from its grounding in nature, becomes hopelessly unstable. If knowledge of natures are simply creations of the mind imposed on the world based on observation of singulars, then the entire structure of our knowledge ends up being a house of cards. Once a nominalist starts to question how he knows, having committed the explanation of reality to the inscrutable divine will, it is only a matter of time before he reaches the conclusion that he knows nothing at all and that what he calls "knowledge" is, in reality, nothing. That process of degeneration is what we call modern philosophy, and fundamental theology gives an answer to it.
II. The Degeneration of Nominalist Knowledge
Although we clearly disagree on the reasons for the degeneration of knowledge, I can certainly agree with the presuppositionalist on the process of degeneration. In that respect, I can commend this summary by the Orthodox presuppositionalist Jay Dyer of the process. Jay also cites an article by Russ Manion titled "The Contingency of Knowledge and Revelatory Theism" that traces the history, which likewise provides a nice summary of modern philosophy's wrangling with this problem. In short, we do not disagree about what happened, only why it happened.
The beginning of the Enlightenment can reasonably be traced to Descartes. Given the enormous optimism of humanist endeavors, he must have believed that human knowledge undoubtedly rested on a sure foundation, and he set out to demonstrate this with in the context of nominalist mind-body dualism with his cogito. This set the stage for the nominalist foundational project, the attempt to ground knowledge in indubitable (properly or doxastically basic) first principles, which would be doomed to failure. This is often given the misnomer "classical foundationalism," but that is anachronistic, since the project itself would only arise within a nominalist metaphysics. The idea of a mind separate from the body in the world is impossible if one accepts human nature as what it is, but the nominalist denies this, which creates the need for this project of justifying knowledge from indubitable a priori principles. This process may be ridiculous to the point of absurdity from the view of hindsight, but it clearly was not considered to be so at the time, and there are reasons that this was the case.
The empiricists then start to question how we get from even those "indubitable" principles to knowing anything about the world. The quintessential nominalist skeptic is David Hume, and there is a reason that Dyer more than once refers to a later philosopher saying that Hume represented the death of epistemology, citing especially W.V.O. Quine's conclusion that epistemology has become psychology. Hume's interpretation of the Peripatetic axiom that knowledge only comes through the senses (which in turn goes back to Aristotle) gives that principle a nominalist reinterpretation. Thus, what is experienced by the senses into sense "data" that are interpreted by the mind in nominalist fashion. That is not characteristic of realist metaphysics. For example, the Thomist agent intellect assumes the activity of judgment in human nature, the Scotist idea of intuitive cognition considers the question of apprehension directly, and it is likely that even Aristotle must have had a similar inchoate assumption of active intellection, even if he never developed the point in detail. In other words, a more fair representation of the Peripatetic axiom would be that knowledge comes not from the sensory powers themselves from being a person using his senses. But when the mind is severed from nature in nominalist fashion, Hume's problem becomes acute.
The next turning point is Immanuel Kant, whom Dyer quotes as saying that he had been "awoken from his dogmatic slumbers" by Hume. Kant therefore recognizes the problem that Hume has raised and tries to solve it. He distinguishes the noumenal and phenomenal realms and tries to reproduce knowledge with resort to a priori categories, such as Aristotle's categories, morality, and logic, that interpret the phenomenal, which we cannot know in itself. This essentially defines the course of the modern philosophical project, which ends up offering more failed attempts to answer Hume's question of how the world and our minds are connected in the nominalist metaphysical paradigm. Dyer aptly cites Imre Lakatos, Nelson Goodman ("The New Riddle of Induction"), and Quine, the last of whom ends up observing that everything from Kant and after has really done nothing to go past the questions that Hume had asked. But it is also hardly a coincidence that Goodman and Quine wrote an article titled "Steps toward a Constructive Nominalism." The framework for the entire discussion has been nominalist.
The primary post-Kantian approaches for nominalist philosophy were phenomenology and mathematical idealism, each grasping one horn of the noumenal-phenomenal dilemma. Phenomenology is exemplified by Husserl's attempt to grasp phenomenal experience as such, and this project would turn out to be the closest that nominalism would get back to its ontological roots. In fact, the critical techniques involved in phenomenalist epistemology would end up being useful tools for metaphysical realists to be more epistemically self-conscious. But Husserl's project was itself unsuccessful as an attempt to ground knowledge in a nominalist paradigm, and neither was Heidegger's attempt to ground knowledge in the experience of time. Sartre's existentialism seems to be the inevitable result of phenomenology without metaphysical realism.
On the other hand, mathematical idealism was the attempt to derive nominalist knowledge through a priori formal systems such as logic and mathematics. This interacted with the modern interest in semiotics, the study of signs and meaning in language, begun primarily by Ferdinand de Saussure and Charles Sanders Peirce and fitting harmoniously with the work of Gottlob Frege in logic. The idealist project had started with empiricists such as George Berkeley, but the most ambitious attempt was that of Bertrand Russell, who combined logic, mathematics and semiotics in an effort to discover an ideal logical language, effectively reducing all of philosophy to the nominalist epistemological project. The Vienna School can be considered an overall philosophical project along the same lines. This was paralleled by David Hilbert in the physical and mathematical sciences in what would be known as Hilbert's Program.
Russell's and Hilbert's attempts were ultimately defeated by Kurt Gödel, whose incompleteness theorems disproved the idea of a self-proving formal system. Alfred Tarski explicitly applied this conclusion to the logical definition of truth in his undefinability theorem, which Tarski acknowledged as having already been reached more or less explicitly by Gödel. Likewise, Kuhn's critique of natural scientific theories in The Structure of Scientific Revolutions leaves science similarly unable to provide the epistemic certainty than the nominalist account of knowledge would require. The Tarskian idea that truth can only be defined within a language as a result of linguistic holism has now been generally accepted, but the Kantian question of how that linguistic truth maps to the phenomenal realm (i.e., what is the truthmaker of statements) and the Humean problem of induction remain unanswered. Despite attempts by Quine, Gödel, Donald Davidson, Saul Kripke, J. L. Austin, John Searle, Wilfrid Sellars, Richard Rorty, and others to remedy that deficiency, I am inclined to agree with the assessment of the later Wittgenstein that the nominalist roots of the problem necessarily lead to an irreconcilable skepticism about knowledge. The attempts to recover a "Platonist" account of knowledge, apart from the Christian history of Western philosophy, in order to reverse the damage done by nominalism do not appear to have been successful.
III. Postmodern Angst: Postmodernism, Fundamentalism, and Christian Presuppositionalism
The implosion of the nominalist account of knowledge leads to a couple of subsequent attempts to construct a metaphysical system in the ruins. But neither of these seems to be successful as a Christian philosophical system that can consistently proclaim that Jesus is God.
The most significant, at least in terms of historical impact, is Jacques Derrida's postmodernism. As mentioned above, postmodern is not merely referring to the fact that the system originated after the modern critique. Instead, it refers to the fact that the system denies meaning anywhere other than the interpreting subject. In order to solve the problem of knowledge, it simply denies that there is a truth out there to know. What we call knowledge is a statement about ourselves or, perhaps more aptly, an expression of ourselves. While I suppose that one might see Derrida's creative interpretation as something like the image of God as Creator, I do not see any way that it can give us any real and meaningful relationship with the historical person Jesus of Nazareth or to affirm that He is God. Therefore, I do not think it can be considered Christian.
The flip side is to try to assert fundamental beliefs of Christianity as themselves being undeniable, which is known as fundamentalism. This is nothing but a specific form of fideism, in which beliefs accepted by an act of will are posited as axioms upon which an epistemology of certainty can be built. It is nothing more than an attempt to bootstrap one's way around Hume's and Kant's skepticism of knowledge, but it doesn't reply to any of the metaphysical problems of nominalism that created the situation in the first place. It accordingly fails to answer the epistemological critique.
Christian presuppositionalism is a more sophisticated approach for explaining knowledge as such, but it is built on the same broken nominalist foundation from which Hume's and Kant's critiques emerged. It attempts to answer Hume and Kant on their own ground, and there is no place on that ground where a stable platform for proclaiming Jesus is God can be constructed. Specifically, the Calvinist Cornelius Van Til, who may reasonably considered the first such presuppositionalist, adopts the gap between noumena and phenomena taken from nominalism that forms the basis of Hume's and Kant's critiques. But he maintains that this gap can be bridged with the submission to the revealed truth of the Trinity, so that this act of submission of the will supplies a missing foundation for all of knowledge that can never have been coherently explained prior to its reception. Confronted with the inconsistency of having taken for granted knowledge that cannot be explained without this revealed truth, the unregenerate unbeliever can presumably be thereby humbled in such a way to be more likely to submit to this revealed truth. Alternatively, the unbeliever who stubbornly insists on his refusal to submit would demonstrate that his unreasonable position was a result of his pertinacious denial of God, not as a result of reason. Either way, the presuppositionalist would have confronted the unbelieving critic with an irresistible argument for his own inconsistency, the transcendental argument for God (TAG), requiring the unbeliever to face that his position is unreasonable.
Unfortunately, at least in the recent debates with Jay Dyer that I have seen, I do not believe that Dyer's opponents are actually interacting with presuppositionalism as a system, an observation echoed by Catholic blogger Paleocrat who has started an entire series on Catholic presuppositionalism. Dyer's opponent Trent Horn, both in the debate and in his debrief with Jimmy Akin, seems to have confused presuppositionalism with presuppositional argumentation, which is not really the same thing. As far as I can tell, they have interacted with the Trinity used as a presuppositional argument, as opposed to submission to the revealed belief in the Trinity being a doxastic requirement in order to be able to reason at all. They have also been dismissive of Dyer's particular presentation of presuppositionalism, which is an extremely difficult task with time constraints of a debate and which is generally going to require opponents to at least accept some basic philosophical premises for the sake of argument so that the discussion can proceed. That this has been the outcome is unfortunate, because presuppositionalism has enough of a following in the Christian community that it deserves interaction.
Along those lines, the presuppositionalist critique of autonomous reasoning, which would include the inconsistency of natural theology or any other account of truth not expressly submitting to belief in the Trinity, is not exactly obscure. Van Til, Greg Bahnsen, and Gordon Clark should not be unfamiliar names in apologetics. At a sophisticated level of apologetics with an informed audience, Dyer should be allowed to take the background for granted and to show how he is applying it to Orthodox theology without needing to reinvent the wheel. Likewise, when Hume's problem of induction and Kant's critique of pure reason are raised, even that invocation is itself cursory or laden with philosophical jargon, it should receive a response. Otherwise, the inference people may draw is that we don't take those problems seriously, which has implications for debates with atheists, Muslims, Unitarians, and others who question the coherence of the Trinity.
I will try to avoid that and to be explicit in why I reject Christian presuppositionalism (both generally and in its Orthodox application). I deny nominalism as an acceptable premise for Christian philosophy, and I therefore reject both presuppositionalism (including TAG) and the Humean-Kantian critique as non-Christian in their assumptions. I have a number of reasons for the rejection of presuppositionalism and the use of TAG, and I propose my own alternatives for how Christianity answers the Humean-Kantian critique.
IV. Arguments against Presuppositionalism as a Christian Approach
First, the separation of noumena and phenomena as implicitly posited by Descartes, Hume, and Kant is a denial of the Christian account of human nature. We have a primordial awareness, sometimes called intuitive cognition, of the unity constituted by our individuality as persons perceiving reality, which we can no more doubt than that we can doubt our own existence. But we have that apprehension of ourselves and the things around us whether we are reflective on it or not; the ontology of being a thinking person precedes reflecting on being a thinking person. So it is not "I think; therefore, I am" but rather "I am; therefore, I am thinking." The entire epistemological project in nominalism is therefore based on a denial of what human beings are, and it unsurprisingly produces a skepticism that is incompatible with human knowing, since it is based on a misunderstanding of human nature as such.
Second, the use of God as a premise in a formal epistemological system presumes knowledge of God to a level of certainty that denies divine infinity, thus succumbing to idolatry. This was the same error committed by Eunomius when he attempted to use the Father's property of ingeneracy as a basis for knowledge. But divine infinity precludes sufficient conceptual knowledge for the nature of God to be the basis of epistemology. Moreover, because it is based on the Cartesian dualist account separating noumena and phenomena, it exaggerates the rational capability of the mind alone to a point that even Eunomius, who at least recognized the possibility of knowledge about natures from the senses, would not accept.
Third, Christian presuppositionalism does not survive the nominalist internal critique deployed by Gödel and Tarski, because the existence of God is explicitly used as a formal axiom within the system for purposes of coherence. What the incompleteness theorems and the undefinability theorem prevent is the attempt to demonstrate the truth of the system by its own axioms, which is exactly what TAG does in its attempt to display its superiority and consistency. But there is no paradigm-independent way to demonstrate that conclusion in the first place. One can think of TAG as the "magic glasses" theory, so that paradigms are like sets of spectacles that can be tried on until one finds the one that lets one "see the truth." But Gödel proved not only that there are no magic glasses but also that magic glasses are in principle impossible. There is no way within any paradigm to see around the glasses so that one would know that what one is seeing is "true" with reference to the use of the glasses. But once one appeals to external knowledge, such as revealed knowledge of the Trinity, that concedes that one cannot build epistemology from within the epistemic formalism, which is a defeater for TAG. Thus, TAG fails for the same reason that Russell's ideal language project and Hilbert's Program failed.
V. Practical Concerns with Presuppositionalism
Apart from the general concerns about relying on arguments that are false, I consider the use of TAG particularly problematic because it creates the false impression that we can achieve a level of confidence in our own finite knowledge that is impossible. The problem with Descartes, Hume, and Kant is that their nominalist metaphysics erodes their confidence even in their own experiences, so that they are searching for a level of certainty in knowledge that is "incorrigible" or "indubitable" around which all other knowledge must be justified in order to count as knowledge. The resulting quest for magic glasses is quixotic; one is likely to end up like Quixote in dubbing a shaving basin "the Golden Helmet of Mabrino."
Not that a foundational argument based on the authority of the Church is any better. Specifically, especially in the so-called "manualist" tradition, there was an attempt to reinterpret the Peripatetic axiom (that knowledge only comes through the senses) and Magisterial authority in Scholasticism into a kind of Cartesian epistemic certainty as an answer to nominalism. That would be nothing other than the nominalist project in Catholic language, which would rightly be called "classical foundationalism," which really means reinterpreting classical philosophy in Cartesian foundationalist terms. This false certainty is nothing but the obverse of the naive assertion of Scriptural authority, sola Scriptura, to perform the same function in Protestant apologetics.
Of course, I certainly believe that there ought to be a normative Magisterial authority in the Church, in the same way I believe that states ought to have a government and laws with normative authority. But that is hardly the same thing as source of necessary epistemic certainty, an epistemic authority, which concept leads only to flailing attempts to answer hopeless questions like "how do you know for sure what is Christian dogma, if you are not infallible?" We ought not to expect to have more certain epistemology about religious matters than we do about anything else, and Hume's and Kant's expectations for epistemic certainty are unreasonable to the point of impossibility. It doesn't work for them because it doesn't work for anyone in any field of endeavor.
In general, the quixotic quest for epistemic certainty, either presuppositionalist or foundationalist, leads to a situation I call "glass cannon apologetics." Presuppositionalists who place all hope for theological knowledge in TAG or similar arguments must be fully invested in this argument in a way that goes beyond normal engagement. When the battle becomes a clash of presuppositional systems, it is an all-out war where one must destroy or be destroyed, which requires one to perfectly protect one's own position from being shattered while devastating the opponent. In normal philosophical discussion, theories are like swords; one might slash, stab, club, or parry with it, and it can absorb and inflict a lot of punishment. It's also relatively easy to drop a sword when it breaks to pick up another one, and one isn't generally too concerned to leave it on the battlefield in the event that one needs to retreat. But when your weapon is a glass cannon, you can't abandon it, and you have to protect it at all costs.
Apart from the incentive toward bad behavior in argumentation that this creates, TAG itself casts one's opponents as being incapable of reasoning, and that makes it extraordinarily difficult, bordering on impossible, to display charity for one's opponent. The presuppositionalist would have basically started the debate in the position that his opponent is less than human in some sense; the opponent has not only made a mistake, but he can't even think straight. In encountering various bad arguments over time, once I have reached the point that I don't think someone can even think straight, I conclude that's the moment at which there is no more discussion to be had. In that respect, the presuppositionalist is starting in a position where dialogue should normally be ending.
In short, I believe that presuppositionalism, apart from being a bad argument from a Christian perspective, is toxic for dialogue. It's therefore best that Christians have ready answers to it so that we can nip it in the bud rather than allowing it to proliferate, from whence proceeds my concern that Trent Horn's response was inadequate. And of course, Christians ought not to make the arguments in the first place. The skepticism of Hume and Kant is not the right starting point for evangelization. With that in mind, I turn to some specific theological problems with presuppositionalism.
VI. The Noetic Effects of Sin
Reformed theologians who use the "magic glasses" approach of TAG account for the existence of multiple paradigms by the so-called noetic effects of sin. This localizes the denial of God at the heart of wrong paradigms as the effect of sin, contrasting autonomous reasoning due to the willful denial of God as contrasted with theonomous reasoning. Before the fall, the human noetic faculties were functioning perfectly, since Adam was in a healthy relationship with God, but breaking that relationship caused the noetic faculties to deceive us. This essentially reads the Humean-Kantian view of epistemic certainty into Scripture and then uses sin in the Reformed view as an explanation for the condition. But again, that aspiration to a noetic faculty of epistemic certainty is itself a kind of Pelagianism. That Pelagianism in turn fits with the prelapsarian Pelagianism entailed in the covenant of works, characteristic of Calvinist soteriology. As I explained in my article, Nicene Christian theology is incompatible with Calvinism, so fundamental Christian theology does not allow orthodox Christians to accept this belief.
It is certainly true that sin has noetic effects, but those effects are not impairment of the faculty of knowledge itself. Rather, the inherent finitude of human knowledge intersects with the temptation to sin in the form of concupiscence to create the misuse of knowledge. It is not that we do not know things but that we use what we know unwisely. Indeed, one of those temptations is to think that we need to know more than we do, as if the finitude of our knowledge is itself evil, which falls in the general line of thinking that material being is itself evil and causes us to covet God's own omniscience. Realizing the limits of human knowledge should not cause skepticism of human knowledge but rather acceptance of human knowledge for what it is, a limited yet good and fruitful capacity of human nature that finds its proper use in seeking for God.
The Biblical account of this situation is clear. Ecclesiastes 1 says at verses 14 and 18 that "I have seen all the works that are done under the sun; and, behold, all is vanity and vexation of spirit…. For in much wisdom is much grief: and he that increaseth knowledge increaseth sorrow." Manifestly, this is not intended to suggest that the created faculties that produce wisdom and knowledge are evil or vain. Rather, they are being used in vain. This is the condition of sin, in which all of our good faculties are misused in self-interest and the pursuit of passions. Just as our desires are fragmented into pointless vanity, so the truths that we may genuinely know serve no good purpose.
In Western theology, this was articulated by St. Augustine as the difference between scientia and sapientia, referring to true wisdom. This true wisdom lets us apprehend God and our ultimate purpose of communion with him, letting us use our knowledge wisely and humbly, not vainly. Such wisdom serves the love of God and neighbor. This is contrasted with the natural man, bereft of grace, who misuses his gifts. Scripture speaks of such men as follows: "The fool says in his heart, 'There is no God' [Ps. 14:1]." "The natural person does not accept the things of the Spirit of God, for they are folly to him, and he is not able to understand them because they are spiritually discerned [1 Cor. 2:14]." "For although they knew God, they did not honor him as God or give thanks to him, but they became futile in their thinking, and their foolish hearts were darkened [Rom. 1:21]." It is not that they lack knowledge, but they lack the love that makes knowledge meaningful. "And if I have prophetic powers, and understand all mysteries and all knowledge, and if I have all faith, so as to remove mountains, but have not love, I am nothing [1 Cor. 13:2]."
The intimate connection between charity and knowledge is itself a result of creaturely finitude. We are not monads existing independent of others. Rather, every one of us necessarily depends on other human beings to be able to be able to achieve a significant degree of knowledge about the world. That dependence is a reflection of our finitude that is not itself evil, and it promotes trust and community. The capacity to make mistakes due to finitude should, if rightly understood, cause us to reach out to those around us so that we can form more human connections and reach more truth. But knowledge sought for its own sake, a result of the brokenness of the fallen world, instead further promotes division. This idol of knowledge for its own sake is symbolized by the Tower of Babel, which caused the scattering of peoples not because it collected too much knowledge but rather because the knowledge was not in service of the ultimate truth, which is God.
VII. Orthodox Critiques of "Natural Theology"
Turning now to the Orthodox version of presuppositionalism, one favored critique among Orthodox presuppositionalists comes from Fr. Justin Popovic in "The Theory of Knowledge in Saint Isaac the Syrian," which can be found in his work Orthodox Faith and Life in Christ. Part of the problem with bringing this work into the contemporary context is that the Europe in which Fr. Popovic was operating was overwhelmed by nominalist philosophy. This is a telling quote about natural knowledge from Fr. Popovic's essay:
Natural laws do not exist for faith. St. Isaac emphasizes this very strongly: "All things are possible to him that believeth" (Mark 9: 23), for with God nothing is impossible. Natural knowledge constrains its disciples from "drawing near to that which is alien to nature;' to that which is above nature.'"
This natural knowledge to which St. Isaac refers appears in modern philosophy under three headings: realism based on the senses, epistemological criticism, and monism. These three approaches all limit the power, reality, force, worth, criteria, and extent of knowledge to within the bounds of visible nature - to the extent that these coincide with the limits of the human senses as organs of knowledge. To step beyond the limits of nature and to enter into the realm of the supernatural is considered to be against nature, as something irrational and impossible, forbidden to the followers of the three philosophical paths in question. Directly or indirectly, man is limited to his senses and dare not pass beyond them.
Nevertheless, this natural knowledge, according to St. Isaac, is not at fault. It is not to be rejected. It is just that faith is higher than it is. This knowledge is only to be condemned in so far as, by the different means it uses, it turns against faith. But when this knowledge "is joined with faith, becoming one with her, clothing itself in her burning thoughts," when it "acquires wings of passionlessness;" then, using other means than natural ones, it rises up from the earth "into the realm of its Creator;" into the supernatural. This knowledge is then fulfilled by faith and receives the power to "rise to the heights;" to perceive him who is beyond all perception and to "see the brightness that is incomprehensible to the mind and knowledge of created beings." Knowledge is the level from which a man rises up to the heights of faith. When he reaches these heights, he has no more need of it, for it is written: "We know in part, but when that which is perfect is come, then that which is in part shall be done away." (1 Cor. 13: 9-10) Faith reveals to us now the truth of perfection, as if it were before our eyes. It is by faith that we learn that which is beyond our grasp - by faith and not by enquiry and the power of knowledge.
"Realism based on the senses" is the naive realism that I've described earlier, "epistemological criticism" is the Kantian approach, and "monism" refers to Berkeley's denial of the reality of anything outside of minds, so that there is only one substance (ideas). In each case, there are postmodern versions of all of these ideas that aren't susceptible to the criticism, but Fr. Popovic has in mind the the naive versions steeped in the nominalism of the time.
The process is described by St. Isaac as follows:
To explain yet more clearly the mystery of knowledge, St. Isaac presents further definitions of both knowledge and faith. "The knowledge that is concerned with the visible and sensual is called natural; the knowledge that is concerned with the spiritual and incorporeal is called spiritual, for it receives its perception through the spirit, and not through the senses. The knowledge that comes by divine power, however, is known as supernatural. It is unknowable and is higher than knowledge." "The soul does not receive this contemplation from the matter that is outside it," as is the case with the first two kinds of knowledge, "but it comes unexpectedly by itself as an immaterial contained within itself, according to the words of Christ: "The kingdom of God is within you." (Luke 17: There is no point awaiting its appearance in outward form, for it does not come "with observation." (Luke 17: 20)).
First, this process definitely rules out presuppositionalism of any stripe. TAG operates by epistemological criticism, the conditions required for knowledge, which cannot produce knowledge of God according to Fr. Popovic. To the extent it destroys confidence in knowledge entirely, it denies Fr. Popovic's observation that natural knowledge "is not to be rejected." Fr. Popovic knows the Humean-Kantian critique intimately, but unlike Van Til and Bahnsen, he does not concede the validity of that critique. Rather, he correctly places that critique within natural knowledge as one of the means it uses to turn against faith. By contrast, Dyer demurs that the use of Kant and Hume is "just asking questions," but that obscures the motivation for asking the questions in the first place, which is epistemological criticism. Asking those questions is motivated by doubt in reason itself, and that is inconsistent with the idea that reason is created by God.
In doing so, Dyer has confused knowing about God with knowing God; "natural theology" allows us only to do the former but not the latter. It is not an attempt to bypass grace or to pretend that we can have God's friendship, to walk with God in the cool of the evening as Adam did by the sheer power of our reason. Nor is it an attempt to affirm an impersonal God that somehow develops into a personal God. Natural theology tells us both that God must be personal and that God must reveal Himself to us in order to be known. As Fr. Popovic maintains, that natural (or spiritual) knowledge of God ought not to be an obstacle for faith; it testifies about God Who is known to be unknown. Natural theology, correctly understood, would cause us to wait on revelation if we have not received it and to trust in revelation if we have, not to descend into rebellious autonomy against the Christian life. It is absolutely true that natural theology can be used in a way that violates the purpose of reason, but that is a misuse of reason, not its absence.
In short, Fr. Popovic's critique, while it might well have been apt against contemporary views at the time, does not rule out classical apologetics or theology, although it might well rule out classical foundationalist approaches, whether Catholic or Protestant. In any case, it certainly doesn't support the presuppositionalist approach.
VIII. The "God in General" Canard
One of the most frequent criticisms of natural theology leveled by presuppositionalists is that natural theology proves a "God in general," an impersonal monad that not only fails to be identical with the triune God of Scripture but is another god entirely: the god of the philosophers. The reason that is untrue is that natural theology never reduces God to a concept. Rather, the reverse is true; the presuppositionalist is the one who has reduced God to a concept by demoting Him to a formal axiom of a system as a basis of justified true belief. In other words, the philosophers have reached erroneous conclusions about God. In natural theology, by contrast, God is a real entity not reducible to a concept. Any sound natural theology concludes that God is an infinitely thick metaphysical reality that cannot even possibly be conceptualized, although true things can certainly be said about God.
A related concern, but one that ought to be taken more seriously, is the concern of apologetics against monotheistic religions, primarily Judaism and Islam but also including Christian oneness sects. For example, Qai at Orthodox Shahada has raised concerns that if one confesses monotheism based on natural theology, then one might have put oneself on the defensive against a Muslim arguing the doctrine of tawhid (oneness) as against the Trinity. Dyer has likewise elsewhere suggested that the Trinity is "tacked on" to God-in-general. The response to that concern is exactly the same argument from transcendence raised above: that we know what we don't know about God.
In the context of this argument, it's a misunderstanding of divine simplicity in the context of natural theology. Since all we know about God is through creation and since natural theology reveals God as Creator, we don't have a basis to know God's internal operations except by analogy. With respect to those external activities, everyone who affirms monotheism would necessarily see the same things in creation. The question is only whether what is knowable about creation properly rules out the possibility of the Trinity or instead whether the claim that God is a Trinity is unknowable based on natural knowledge. What we can conclude from the type of unity in God to the extent it is knowable from natural revelation is that God's mode of being generally and His mode of being one (simple) is a fundamentally different mode of existence from created things. In terms of the Catholic understanding, that is agreed by both Thomists and Scotists, the latter of whom affirm univocity of predication about God but who still affirm God's perfections in an infinite mode. Moreover, the concept of divine simplicity is identical in East and West, although there are differences on the implications of that doctrine for metaphysics generally in terms of exactly how creation relates to God, including whether God's activities are with respect to creation are entitative (energies, logoi) or relational. At any rate, if we understanding what we mean by the divine simplicity, then we would know that it cannot be used to formally rule out the Trinity, because it would require us to posit knowledge about the inner life of God that we can't possibly have based on the nature of divine simplicity. (It is also possible that one could argue that the Trinitarian nature of God is knowable from natural theology and analogy. To date, I have not found those arguments compelling, although I am intrigued by Joshua Sijuwade's argument from love defined as willing the good for another.)
As one example of a failed concept, the Islamic doctrine of tawhid is too small. It is modeled on earthly sovereignty and makes God an exceptionally powerful being among beings, as opposed to the transcendent Creator of all that is. That is a false conception of God, so they have not correctly reasoned as a matter of natural theology. It is not a question of the Trinity being "tacked on" to a common concept of God but rather that the Muslim's concept of God simply is not the one held by Christians or correctly reasoning natural theologians at all. And again, we have to contrast knowing God with believing things about God. When we say that Muslims worship the same God, we do not mean that they have true beliefs about God. Rather, we mean only that they have attached a defective concept of God to the actual God who has taken certain acts in history. For example, they correctly attribute that God in question is the one God who created everything.
The same would be true of anti-Trinitarian Judaism, which is comparatively rare because Trinitarian doctrine does not philosophically contradict divine oneness. (The rejection of Christianity is typically due to rejection of the historical fact of Jesus as Messiah as opposed to the philosophical rejection of the Trinity or the Incarnation as incompatible with divinity.) The God revealed in the Old Testament is correctly identified with the one God Who created all things, so there is certainly a common foundation. But to the extent that there is a defective interpretation of the revealed concept that "God is one," much like the defective Islamic concept of tawhid, it is a wrong philosophical description of God. It says something false about the God they have correctly identified. The Trinity cannot be "tacked on" to that defective concept; the defective concept must be corrected, either by correct interpretation of Scripture or by showing that the characteristics of God apparent from nature cannot exclude the Trinity.
In short, the reason that the "god of the philosophers" is problematic is not that the concept is known through natural theology (methodology) but that it is mistaken. The "god of the philosophers" does not mean that the concept results from philosophy but rather that the (erroneous) concept is held by certain philosophers.
IX. The Failure of the Critique against Catholicism
This critique from the East ought to be well-taken to the extent that Catholic thinkers can fall captive to naive philosophy, even when they believe themselves to be ancient. John Deely's Four Ages of Understanding is an essential work for articulating the process by which philosophy developed over time, especially the metaphysics of signs that is essential to conscious epistemology in Thomism. One might consider it the definitive counter-narrative to the assertion that Catholicism is "realism based on the senses," as per the anachronistic reading of the Peripatetic axiom. As I previously noted, this was not an issue of philosophy lacking the capacity to think consciously about epistemology. Rather, much of that conceptual apparatus was taken for granted. Nevertheless, in the West, there was thought given to these questions, particularly in the study of logic, before the issues associated with Ockhamism and modernism overwhelmed that discussion. The Cappadocians engaged in a similar project of conscious epistemology in the East in the context of replying to Eunomius, and although the focus in the East was primarily on the need for Christian practice, that should not be taken to imply that this was unique to the West. Rather, both East and West affirmed the same fundamental idea that natural knowledge could lead to knowledge about God but only grace, in the context of Christian life, could provide knowledge of God.
The confusion between those two reflects confusion in the question of ens intentionale, intentional being. In their consideration of the metaphysics of signs, Catholic authors over the centuries developed this understanding of the relationship between knower and known in a conscious way, with the most explicit expositors being St. Augustine, St. Thomas Aquinas, John Poinsot, and Bl. Duns Scotus (in the application to his own metaphysical system). Although it may be fair to say that this study was somewhat neglected because of other more pressing considerations, especially as modernism took hold, it is wrong to say that Catholicism did not have epistemological solutions. What is common to all of these solutions, at least to the extent that they are successful, is that they follow Stephen Chamberlain's observation that "epistemological critique is intended to supplement rather than ground ontology in the explication of human knowledge."
By "successful," I mean that the critique is not based on denying the real relation between the knower and the known that underlies knowledge. That is the linchpin of Catholic philosophy on this point. In my opinion, Jacques Maritain and John Deely are the two best expositors of conscious epistemology in the Thomist tradition, in terms of giving an explicit response to the modernist epistemological critique after Kant while also answering the phenomenological turn of Husserl and others. Maritain and Deely are only following St. Thomas's account of intentional being, in terms of giving a rigorous exposition of the sign relation and its metaphysical basis. In Deely's case, this also incorporated much more recent work on logic and language in the analytical tradition, especially Peirce's account of signs.
In terms of responding to Kantian philosophy and so-called "transcendental Thomism," I commend Out of a Kantian Chrysalis?, which collects and analyzes Maritain's critique of the transcendental Thomist Fr. Joseph Marechal. Much of what Maritain says would apply to transcendental approaches generally, including Christian presuppositionalism. In my opinion, Maritain also gets the better of Gilson and his epistemological disciple Frederick "Fritz" Wilhelmsen in terms of answering the transcendental critique without swinging the pendulum to the opposite side of reducing knowledge to sensory impressions, which is precariously close to turning the Peripatetic axiom into the modernist "sense data." I therefore agree with Chamberlain that Maritain's position strikes the correct balance in responding to the Kantian critique, and importantly, that difference on epistemology does not entail a fundamental conflict on what being actually is in the Thomist metaphysics. Both Maritain and Gilson end up in the Neo-Scholastic Thomist line of philosophy, not the modernist schools. They agree with the essence/existence distinction; they only disagree about how existence is known.