Model Theory in Theology: From Descartes to Luther

This short talk given on August 12, 2026, at the 15th International Luther Congress in Aarhus, Denmark, introduces model theory to historians. Like all my papers, it arises from work done at the Department of Philosophical Theology, ILT Christ School of Theology. 

Two Problems We Have Not Escaped

I want to begin some distance from model theory, with two problems associated above all with Descartes. The first is the problem of the external world. How do I know what the world is like apart from my representations of it? The second is the problem of other minds. How do I know what another person thinks, means, intends, believes, or experiences when I never occupy that person’s consciousness?

Descartes formulated these problems with unusual clarity. Four centuries later, we have not made them disappear. We have mostly learned how to live intelligently with them. We do not solve either problem by somehow getting outside ourselves. Rather, we encounter something over against us, something that resists us, and we try to render it intelligible. The world does not always behave as our theories predict. Other persons say and do things our accounts of them do not anticipate. Our interpretations can fail because something confronts us that is not simply at our disposal.

We cannot solve either problem by looking down at reality from nowhere, as though we could step outside ourselves and check our account against the thing itself. But we are remarkably good at a more modest maneuver: looking left and right, comparing one account with another and both with what resists them. That is the maneuver this essay is about.

Historians Live with the Problem of Other Minds

Historians confront the second Cartesian problem every day. At a Luther Congress we ask what Luther meant, what Melanchthon believed, what a late-medieval logician was doing with suppositio, or what theological possibilities were available to an author in 1517. But we cannot climb into Luther’s mind. We have texts, vocabulary, grammatical practices, controversies, other authors, institutional settings, manuscripts, and subsequent writings.

What historians actually do is reconstruct. We construct an account under which this evidence becomes intelligible together. Different historians may agree about the words on the page and nevertheless disagree about the best account of what those words are doing. The text and its historical setting constrain us: they possess what, borrowing loosely from Charles Peirce’s language of Secondness, I shall call an over-and-againstness or “bump-up-againstness.” They do not allow us responsibly to make them say whatever we wish.

This means that the mens auctoris need not function as an independently accessible semantic court of appeal. Authorial intention remains a legitimate historical hypothesis, but what we can reconstruct is the intentionality of a textual act from publicly available historical evidence. Our reconstruction may be excellent without becoming incorrigible.

The Special Sciences Face the External-World Version

The special sciences confront an analogous problem from the other Cartesian direction. The physicist does not have uninterpreted physical reality sitting on one side of the laboratory and a theory on the other. The biologist does not inspect life in itself. Scientists encounter phenomena, measurements, regularities, anomalies, and recalcitrant observations, and they construct theoretical structures that make these intelligible.

The historian’s problem and the scientist’s problem are not identical. A manuscript, another mind, and a physical process are not the same kind of object. But structurally the inquiries share something important: neither historian nor scientist possesses a God’s-eye standpoint. Both construct accounts of something that confronts them and is capable of proving those accounts inadequate. Theories are answerable to what they seek to understand without our having to suppose that finite knowers can compare their theories with an entirely uninterpreted world.

Theology Has Both Problems at Once

Theology inherits both problems. Theologians are historians. We ask what Paul meant, what Augustine meant, what Luther meant, what Nicaea meant, and what inherited doctrinal language was doing in its original settings. But theologians also make assertions about reality: God raised Jesus from the dead; God justifies the ungodly; Christ is present in the Supper.

Theology therefore interprets witnesses to other minds while also speaking about a world in which God is soteriologically ingredient. It asks both what inherited theological assertions meant and what account of God, world, Christ, sinner, promise, sacrament, and salvation renders the subject matter intelligible. The two Cartesian problems meet inside theological inquiry.

This is why theology cannot simply borrow its method from the historian or the scientist alone. It needs a single account of inquiry general enough to cover both tasks at once—one that tells us what we are doing when we build a model of a mind we cannot enter and a model of a God we cannot view from above. That is the account model theory can supply, and it is why I turn to it now.

A Small Luther and Trutvetter Example

Let me give one small example from another paper I presented here. Luther entered the University of Erfurt in 1501, the year Jodocus Trutvetter’s Summule totius logice appeared. We possess Trutvetter’s texts and Luther’s texts. The historical question is not merely whether Luther remembered particular sentences from Trutvetter. It is what semantic and inferential possibilities belonged to the intellectual world within which Luther’s later disputation became intelligible.

Consider a Trinitarian inference discussed by Trutvetter:

This divine essence is the Father.
This divine essence is the Son.
∴ The Son is the Father.

If I assign the copula est strict numerical identity throughout, the inference is valid. If this divine essence is numerically identical with the Father and numerically identical with the Son, then Father and Son are numerically identical with one another. There is no problem with the logic, but the theology is disastrous.

So what must est, essentia, Father, and Son be doing semantically for Trutvetter’s discussion to become intelligible? And when Luther later reasons with inherited scholastic logical vocabulary, what larger structure of interpretation makes both Trutvetter and Luther intelligible?

Here I need to point out that I am using the word interpretation in a way different from its hermeneutical use familiar to many of us. In formal semantics an interpretation assigns semantic values to the non-logical vocabulary of a language—in the simplest cases, the things to which its terms apply. Two readers may agree completely on the visible words and disagree about the meanings being assigned to them.

In historical work we are not pretending that Trutvetter’s or Luther’s prose is itself a formal language. We construct structured interpretations of the texts, and where useful we can regiment selected claims formally. One historian may model the relevant predication one way, another differently. We can then ask which model makes more of Trutvetter’s text, Luther’s text, and the historical relation between them intelligible. We can even ask whether a larger space of intelligibility can accommodate both without erasing their differences.

Theological Language Presents the Same Problem

The same issue appears when we turn from the historical reconstruction of theologians to the theological tradition and the Word of God that confront us. People of good will can agree on the language of theology while interpreting its terms very differently.

Lutherans may say, “We are justified by grace through faith.” But what is the semantic work of justification? What is grace? What sort of relation between God and the sinner is being asserted? Or Christians may agree that “Christ is present in the Eucharist” while operating with very different understandings of Christ, presence, body, sign, promise, and sacrament.

Theological disagreement therefore frequently occurs because the same sentences are satisfied under different models. A model may preserve familiar vocabulary while changing the larger structure in which the vocabulary functions. The question then becomes whether one model preserves more of the theological subject matter, whether another changes the subject, and whether several admissible models remain possible.

Model Theory Makes the Structure Explicit

Only now do I want to introduce model theory in its technical sense—and I will keep the symbols to the minimum that actually does work for us.

A theory, syntactically understood, is simply a set of sentences. Call it T:

T={φ1​,φ2​,φ3​,…}

Read this as: T is just the set of claims the theory makes.

An interpretation assigns semantic values to the non-logical terms of a language. A model is a structure under such an interpretation in which the relevant sentence or theory is true. When a structure M makes a sentence φ true under the interpretation supplied by M, we say that M satisfies φ, and we write:

$$M\models \phi$$

Read ⊨ simply as “satisfies” or, less technically, “makes true.”

A model of a theory satisfies every sentence in it. The collection of all such models is what logicians call Mod(T):

$$Mod(T)=\{M\mid M\models T\}$$

Read this as: Mod(T) is the class of models that make all of T’s sentences true.

And now we can state formally something historians and theologians encounter constantly. One theory can admit more than one model:

M1​⊨T

and

M2​⊨T,

while

~(M1​ = M2​).

The final expression says only that the two models are not numerically identical. More importantly for our purposes, they may differ substantially in the structures under which the same sentences are true. Both can satisfy the theory without representing its subject matter in the same way.

Satisfaction alone therefore does not tell us which model should be preferred. Some candidate models can be excluded because they violate constraints constitutive of the subject matter. An interpretation of a text that cannot accommodate its actual wording may cease to be an interpretation of that text. A theological model that preserves the word resurrectiononly by abandoning the identity of the one said to have been raised may have changed the subject rather than merely offered a less attractive account.

Among the models that remain admissible, we compare. We ask about consistency, coherence, explanatory scope, fecundity, parsimony, applicability, historical adequacy, capacity to accommodate recalcitrant evidence, and sometimes elegance or beauty. These virtues are not mechanically commensurable. There is no algorithm that adds them together and announces the correct model.

This is where I find Kant’s reflektierende Urteilskraft—reflecting judgment—useful. We compare, discriminate, and judge without pretending that an antecedently possessed universal rule mechanically determines the result. I call the structured field within which such comparative judgments occur teleo-space.

The position is fallibilist. Further texts, evidence, experiences, arguments, or distinctions may force us to reorder the models. But fallibility does not imply that every model has equal epistemic standing. We can give reasons why one is better than another.

Nor do we need a God’s-eye standpoint from which model and uninterpreted reality can be placed side by side. We cannot look down from nowhere. But we are remarkably good at looking left and right. We can compare models. We can see that one explains something another leaves obscure, preserves a distinction another destroys, or accommodates an obstinate text or experience another must suppress.

Model theory therefore does not solve Descartes’ problems by giving finite creatures access to reality without mediation. It does something more useful. It clarifies the structure of responsible inquiry when such access is unavailable.

The historian constructs models of other minds from texts that resist interpretation. The scientist constructs models of a world that resists theory. The theologian does both: we interpret witnesses, and we make claims about a reality in which God is soteriologically ingredient.

Our models are fallible. More than one may satisfy the assertions with which we begin. Some can nevertheless be excluded; others can be comparatively ordered. We can offer what I would call a reasoned account: a publicly criticizable, corrigible judgment about how the subject matter may be independently of our present act of modeling it.

We cannot look down from nowhere. But we can look left and right. And perhaps model theory can help theology become clearer about what it is doing when it does.

Reality Does More than Resist; It Corrects

This essay continues an ongoing series in philosophical theology from the Department of Philosophical Theology at Christ School of Theology. The series asks a few basic but demanding questions: What makes reality intelligible? How does theological language work? What philosophical assumptions support Christian belief? Behind it stands a simple conviction: theology exists because these questions exist, and its first task is to make Christian doctrine intelligible without reducing, replacing, or explaining away the reality to which that doctrine points.

The previous essay argued that reality has the first word. Inquiry does not begin because an isolated subject decides to direct its attention toward an otherwise indifferent world. It begins because something has already presented itself, interrupted our expectations, resisted our descriptions, or called our understanding into question. Before we formulate a hypothesis, devise an experiment, or construct a theory, something has already occasioned the inquiry.

That claim reverses an order of explanation deeply embedded in modern thought, which imagines us first as active knowers who subsequently turn toward reality as an object of intellectual activity. The actual experience of inquiry suggests otherwise. Reality does not enter the process only after we have begun asking questions; the questions arise because reality has already refused to remain unnoticed.

From resistance to correction

Resistance alone, however, does not explain inquiry. A locked door resists the body. A steep hill resists the traveler. A malfunctioning machine resists its operator's intentions. Such resistance may frustrate us, delay us, or force a change of behavior, but it does not yet constitute correction.

Intellectual inquiry requires something more: reality must be capable not merely of impeding our purposes but of showing that an account of it is inadequate. A scientist whose prediction fails does not conclude that nature has simply been uncooperative; she asks whether the theory, the measurement, or the experimental design was mistaken. A historian who discovers a document inconsistent with a familiar narrative does not treat it as an obstacle to a preferred interpretation; he asks whether the narrative must be revised. A philosopher who finds a contradiction within an argument does not treat it as an unfortunate collision of equally acceptable possibilities; she recognizes that something has gone wrong. In each case, reality does more than resist. It corrects.

To be corrected is not merely to be pushed in a different direction. It is to discover that one ought to think differently because one's previous account has failed to do justice to its object. This "ought" is already present in every serious inquiry. We do not prefer a revised theory merely because it is newer; we judge it more adequate. We do not abandon a historical interpretation because another has become fashionable; we abandon it because the evidence no longer supports it. We do not reject an argument because it is rhetorically inconvenient; we reject it because its conclusion does not follow or its premises cannot be sustained.

Inquiry is therefore normative from the beginning, for it distinguishes better from worse descriptions, more and less adequate explanations, responsible from irresponsible judgments. Without such distinctions there may still be curiosity, experimentation, or invention, but there is no disciplined search for understanding.

The limits of construction

This is where many contemporary accounts of knowledge become unstable. They rightly emphasize that human knowing is historically situated, linguistically mediated, socially conditioned, and conceptually structured. No one encounters reality from nowhere; every observation occurs within practices of interpretation, and every judgment employs concepts inherited from particular traditions. Yet none of this explains how those practices, concepts, and traditions can themselves be corrected. A community may share an interpretation and still be mistaken. An inherited narrative may organize experience powerfully while concealing what actually occurred. A conceptual scheme may be internally coherent while systematically misdescribing its object. Even a theory of knowledge that insists all knowledge is socially constituted must distinguish a more adequate account of that constitution from a less adequate one.

The language of construction, then, cannot be the final word. Human beings undoubtedly construct theories, models, narratives, and conceptual frameworks. The planetary model, the economic model, the historical narrative, and the theological system all result from acts of selection, abstraction, and representation; no model reproduces its object without mediation. Construction is therefore not the enemy of realism—it is one of the conditions under which finite beings become capable of understanding anything at all. The relevant question is not whether our models are constructed, but whether they remain answerable to what they seek to understand.

The difficulty arises when the constructed character of a model is taken to mean that it owes nothing beyond itself. At that point coherence replaces adequacy, usefulness replaces truth, and a model's capacity to organize discourse matters more than its capacity to disclose its object. A model may be coherent and still false. It may be useful and still distort what it represents. It may secure agreement among those who employ it while excluding every consideration that would expose its inadequacy. That a model works for some purpose does not establish that it has understood the reality with which it deals.

This becomes especially clear when models meet anomalies. An anomaly is not simply something unexpected; it is something that ought not to have occurred if the model were adequate. Its significance lies in the tension between what the model permits us to expect and what reality actually presents. Yet even anomalies do not automatically correct us—human beings are remarkably skilled at protecting favored explanations from inconvenient evidence, whether by dismissing exceptions, redefining terms, altering standards of evidence, questioning a critic's motives, or introducing auxiliary explanations whose real function is to prevent the original account from being tested. A model becomes intellectually responsible only when it permits reality to count against it.

That sentence sounds obvious, but much depends on it. Inquiry requires more than the availability of evidence; it requires a willingness to let evidence exercise normative force. Reality must be granted the authority to expose not only that our expectations have failed, but that our descriptions must change.

The third partner

This is why inquiry always includes what might be called a third partner. There is the knowing subject, with a history, language, community, and set of intellectual practices. There is the theory, model, or interpretation through which the subject seeks understanding. And there is the reality the model intends to disclose.

This third partner cannot be absorbed into either of the others. It is not merely a projection of the knowing subject, because it continually resists what the subject would prefer to find. Nor is it identical with the model, since competing models may address the same reality, and every model remains open to correction by what it fails to preserve.

Once this third partner disappears, inquiry changes character. Disagreement becomes a contest between perspectives rather than a shared attempt to understand something that exceeds them both. Theories are assessed by the identities they sustain, the interests they serve, or the effects they produce, and questions of truth are gradually redescribed as questions of power, coherence, usefulness, or social location. These considerations are not illegitimate—intellectual practices do involve power, interpretations do arise from particular social locations, theories do have consequences—but none of them explains why an account of power, location, or consequence should itself be accepted as more adequate than its alternatives. Even the critique of truth must present itself as a truthful critique.

This inescapability suggests that correction belongs more deeply to inquiry than any particular theory of knowledge does. Before we decide whether we are realists, idealists, pragmatists, or constructivists, we have already distinguished claims that illuminate reality from claims that obscure it, and assumed that inquiry can disclose why one judgment should replace another. The phenomenon is familiar enough that we scarcely notice it: a physician changes a diagnosis because the patient's condition does not fit the original account; a mechanic abandons one explanation of an engine failure because the parts do not behave as predicted; a child revises an assumption about another person because that person's actions keep contradicting it. In each case, understanding advances when the object is permitted to instruct the one seeking to understand it.

This instruction need not arrive as a complete answer. Reality seldom interprets itself in finished form; it confronts us through anomalies, contradictions, absences, patterns, and unexpected relations. We must still reason, imagine, compare, and construct. Correction does not eliminate the active work of the knower—it places that work under judgment.

Creativity and humility

Genuine inquiry therefore requires both creativity and humility. Creativity, because reality does not hand us ready-made conceptual schemes; we must devise models capable of rendering its order intelligible. Humility, because no model can claim immunity from the reality it seeks to understand. The deepest intellectual failure occurs when creativity is preserved but humility is lost—when inquiry becomes the art of producing ever more sophisticated constructions without allowing anything outside those constructions to judge them. The result may be ingenious, influential, even institutionally successful. It will not be understanding.

What correction requires of reality

The claim that reality corrects us goes beyond asserting that a world exists independently of human thought. A merely independent reality could remain mute, chaotic, or wholly unintelligible; it might resist our actions without providing any basis for distinguishing a better description from a worse one. Correction requires more than independence. It requires order.

Reality must possess determinate features and relations that our descriptions can preserve or distort. It must be stable enough that inquiry can discover patterns, rich enough that our first descriptions remain incomplete, and intelligible enough that failure can become the occasion for improved understanding. The normativity of inquiry is not imposed on reality from outside; it arises within the encounter between finite understanding and an order that exceeds it. We discover that we ought to revise our judgments because reality has shown them to be inadequate.

None of this makes correction final. Later inquiry may expose weaknesses in what presently appears to be the better account, and reality does not speak unambiguously—evidence must be interpreted, and reasonable people may disagree about what a given anomaly requires. But fallibility does not abolish correction; it makes correction necessary. The possibility of error presupposes a difference between what we believe and what is the case. The possibility of learning presupposes that this difference need not remain permanent. Inquiry inhabits the space between them—the space in which reality can unsettle our judgments and call forth more adequate ones.

Toward the next question

We can now state the advance beyond the previous essay. Reality has the first word because inquiry begins in response to what confronts us. But that first word is not merely the brute announcement of presence—it is also a claim upon our understanding. Reality does not merely say, "I am here." It says, "You have not yet understood me."

That claim gives inquiry its peculiar dignity. Human beings do not merely adjust themselves to their environments; they seek to become answerable to what is real. They recognize, however imperfectly, that an inadequate description ought to be revised, and that understanding bears responsibilities not exhausted by usefulness or success.

The question that now emerges is deeper still. Norms such as truth, adequacy, and explanatory superiority are not objects situated alongside other objects. We do not observe adequacy as we observe a tree, a molecule, or a distant planet. Yet without such norms, no observation becomes evidence and no theory becomes corrigible. What kind of reality can call forth not merely causal reactions but responsible judgments? What must the world be like if it not only resists our constructions but teaches us how those constructions have failed?

Reality has the first word. We must now ask how that word becomes intelligible as correction.

How can God be Present without Ceasing to Be God?

This essay is part of an ongoing series from the Department of Philosophical Theology at Christ School of Theology. The series asks how Christian faith can speak truthfully of God’s presence in the finite, ordinary, and everyday without reducing God to one more feature of the world or removing God into a distance where presence becomes only metaphor. At stake is a basic theological question: how can God be truly present to creatures without ceasing to be the living God who is not contained by what God creates?

One of the unexpected privileges of growing older as a scholar is discovering that a question asked many years earlier was perhaps better than the answer one was then able to give. In 1993, at the American Academy of Religion meetings in St. Paul, I presented a paper on the Lutheran understanding of theosis. The paper arose within the context of the growing interest in the Finnish interpretation of Luther and its insistence that justification involves not merely the imputation of Christ’s righteousness but the real presence of Christ in faith. I recognized at the time that the historical question—whether Luther could speak of deification—could not finally be separated from a philosophical one. What must reality be like if Christ is genuinely present in the believer and the believer thereby participates in the divine life without ceasing to be a creature?

More than thirty years later, I have come to think that the question posed there was substantially correct, even though the conceptual resources available to me were not yet sufficient for answering it. The issue was never simply whether Luther used the language of deification, nor even whether the Finnish interpretation had properly reconstructed the relevant texts. The more fundamental difficulty concerned the ontological structure of divine presence. If the believer participates in the divine essence itself, the distinction between Creator and creature appears endangered. If, on the other hand, participation is restricted to divine effects or energies understood as something less than God’s own presence, it becomes difficult to see how the resulting account constitutes genuine deification. The problem is to affirm a divine presence strong enough to transform the believer without construing that presence in such a way that the believer becomes an instance or portion of deity.

Said of and Present in

The distinction that first allowed me to formulate the problem came from Aristotle’s Categories. Aristotle distinguishes between what is “said of” a subject and what is “present in” a subject. When human being is said of Socrates, Socrates is identified as an instance of humanity. The name and definition of the universal apply to the particular: Socrates is a human being, and what it is to be human applies to him. When whiteness is present in Socrates, however, the relation is different. Socrates is not an instance of whiteness in the same sense in which he is an instance of humanity. Whiteness inheres in him as a property or accident inheres in a substance.

This distinction has immediate theological importance. If God were “said of” the believer in the Aristotelian sense, then the believer would fall under divinity as Socrates falls under humanity. The believer would become a specimen of God, a token of the divine type. Whatever theosis means, it cannot mean this without surrendering the distinction between Creator and creature. The believer does not become a finite instance of a universal deity, nor does salvation elevate the creature into membership within the divine species.

The biblical language of indwelling points instead toward the “present in” relation. Paul does not ordinarily say that the believer becomes an instance of divinity. He says that Christ lives in the believer, that the Spirit dwells in us, and that those who are in Christ have become new creations. The governing structure is not classification but presence. God is not said of the believer as humanity is said of Socrates, bur rather God is present in the believer as that which gives the believer a new life. This is why the language of indwelling is theologically more basic than the language of participation whenever participation is construed as a particular’s falling under a universal.

Yet the analogy with Aristotelian inherence produces its own difficulty. An ordinary accident depends upon the substance in which it inheres. Socrates’ particular whiteness is present in Socrates and cannot continue to exist once Socrates no longer exists. The substance is the locus of the accident, but it is also the ontological ground upon which the accident depends. God’s presence in the believer cannot possess this structure. God is genuinely present in the believer, but God does not depend upon the believer for being. Indeed, the dependence runs in precisely the opposite direction: the believer depends upon the divine presence for the believer’s new mode of existence.

The Inversion of Inherence

This is what I have come to call the inherence inversion problem. The theological case preserves the location characteristic of inherence while reversing its ordinary direction of dependence. God’s presence is located in the believer, but it is not grounded in the believer. Moreover, the believer does not possess God in the way Socrates possesses his whiteness. Divine presence cannot become one more property belonging naturally to a human substance, something accumulated, controlled, or held as the believer’s own. The believer is the locus of the presence but not its owner and certainly not its source. 

I remember speaking about this during a short presentation at the International Luther Congress in Minneapolis in August of 1993. I told the room that this was a problem, and that we were dealing with a theological accident which allows the believer to be the believer that he is apart from the accident -- this is necessary, I said, to avoid collapsing the creature into the Creator -- while nonetheless not depending upon the believer for its being. Far from being simply an aspect of the believer, divine presence transcends the being of the believer, I averred, but cautioned that such a way of being seemed impossible on strictly philosophical grounds. 

The 1996 continuation of the argument approached this problem by examining seven models of the unity between Christ and the believer. In "The Ontology of Deification" written for the Mannermaa Festschrift published the next year, I concluded that the traditional language of the Mystical Personal Union, understood through the category of perichoresis, provided the least inadequate account. The union had to be stronger than juxtaposition or moral association but weaker than merger or identity. Christ could not remain merely external to the believer, since the language of indwelling and transformation would then lose its force. Yet neither could Christ and the believer collapse into one substance or one person, since the difference between Christ and the Christian must remain.

The difficulty was that perichoresis named the required relation without explaining its metaphysical structure. To say that two realities mutually indwell one another is to identify the phenomenon in need of explanation, not yet to provide the explanation. The final footnote of the 1996 paper gestured toward the idea of the “theological accident" I had spoken about at the Luther Congress, but the concept remained undeveloped. I knew that the divine presence must somehow be genuinely present in the believer while not depending upon the believer, but I still did not yet possess a philosophical account capable of holding these affirmations together.

The conceptual resources needed for such an account emerged only gradually through work on questions that initially appeared quite different: Luther’s Christology, trope theory, divine agency, Davidson’s anomalous monism, metaphysical grounding, model-theoretic semantics, and, more recently, constitutive divine causality. Over time it became clear that these investigations shared a common structural question. How can one reality be genuinely present within another without either becoming identical with it or remaining merely externally related to it? The question arises in the union of divine and human natures in Christ, in sacramental presence, in the relation between divine and creaturely agency, and in the indwelling of Christ within the believer. These are not identical theological problems, but they exhibit a common metaphysical form.

Location and Grounding

The distinction that now seems decisive is the distinction between location and grounding. In ordinary cases of inherence, these relations coincide. Socrates’ particular whiteness is located in Socrates and grounded in Socrates. It belongs to the concrete whole that Socrates is and perishes with the dissolution of that whole. The substance is therefore both the locus of the property-instance and the ontological ground upon which it depends. The theological problem arises because divine presence seems to preserve the first relation while reversing the second. God is genuinely present in the believer, but God cannot be grounded in the believer.

A conceptual resource for understanding this structure appears in Edmund Husserl’s account of Fundierung in the Third of his Logical Investigations. Husserl distinguishes relatively independent parts from non-independent parts, or moments. A piece can, at least in principle, be separated from the larger whole of which it is presently a part and continue to exist independently. A moment, by contrast, is what it is only within a more comprehensive whole or in conjunction with other moments. Color, for example, cannot occur except as extended, while sensibly presented extension cannot occur without some qualitative determination. Such moments are not externally connected items accidentally placed beside one another. Their identities include relations of essential dependence.

Husserl’s analysis is particularly helpful because foundation need not possess only one form. Some relations of Fundierung are reciprocal: each moment requires the other if it is to be the kind of moment that it is. Others are one-sided: one reality requires another, although the latter does not correspondingly require the former. Foundation may also be immediate or mediated through more comprehensive relations among moments and wholes. Husserl thereby provides a vocabulary for articulating ontological dependence without reducing it either to efficient causation or to logical implication. To say that one reality is founded upon another is to say that the first cannot be what it is apart from the second, not necessarily that the second caused it at some earlier moment.

This distinction allows the structure of divine indwelling to be stated more carefully. God does not depend upon the believer or upon the union between God and the believer in order to be God. The relation of indwelling, however, cannot be this particular relation apart from both God who is present and the believer in whom God is present. The relation is founded upon its relata without thereby making those relata reciprocally dependent in their being. The believer’s renewed life exhibits a still clearer asymmetry: it is founded upon the divine presence, while God’s being and power are not founded upon the believer’s natural capacities. The believer requires the divine presence for the believer’s new life; God does not require the believer in order to be God.

Husserl therefore clarifies the structure of dependence involved, but his account does not by itself settle the question of ontological source. His principal concern is with the relations among parts, moments, and wholes, rather than with the ultimate ground in virtue of which a particular reality obtains. During the past three decades, contemporary analytic metaphysics has developed a more explicit account of grounding as a primitive relation of ontological dependence. Associated especially with the work of Kit Fine, Gideon Rosen, Jonathan Schaffer, and others, grounding seeks to answer a question distinct from those of causation or logical implication. One thing may obtain because of, in virtue of, or on the basis of another without standing to it either as a causal effect or as a logical consequence. Grounding thus articulates relations of explanatory priority within reality itself. It asks not merely what caused something to occur or what propositions entail it, but what features of reality make it the case that it exists or obtains at all.

Husserl supplies the architecture of dependence; contemporary grounding theory helps identify its direction and ultimate source. Once grounding is distinguished from both causation and location, there is no obvious reason why every property-instance must be located in the same substance in which it is ontologically grounded. The possibility immediately arises that a property-instance might be located in one substance while remaining grounded in another. It is precisely this possibility that proves decisive for the theological problem before us.

Accordingly, I now call a property-instance whose location and grounding belong to different substances an ectopic trope. The adjective ectopic is borrowed from medicine, where it identifies something situated outside its ordinary or expected location. Only the structural feature is intended here. An ectopic trope is present in one substance while grounded in another. Its locus and its ontological home do not coincide.

At this point a brief explanation of trope theory is necessary. Over the past half century, a number of philosophers have proposed that the basic constituents of reality are not abstract universals but particularized properties, or tropes. Rather than speaking of redness as a universal instantiated in many objects, trope theory speaks of this particular redness of this rose and that particular redness of that fire truck—numerically distinct property-instances that resemble one another without being identical. Individual substances are then understood as structured bundles of such particularized properties. Whether or not one accepts trope theory as a complete ontology is not important for the present argument. What matters is that it provides a natural way of speaking about particular instances of properties or presences without treating them either as abstract universals or as independent substances. The divine presence in the believer is not God’s essence abstractly considered, nor is it another substance alongside the believer. It is, rather, a particular presence of God in this believer at this time. Trope theory supplies an ontological vocabulary for describing such particularized presences.

The particular presence of God in the believer can thus be understood as genuinely located in the believer, so that the language of indwelling need not be reduced to metaphor or to the extrinsic attribution of a new status, while the presence remains ontologically grounded in God. It exists and acts in virtue of God’s being and giving, not in virtue of the believer’s natural capacities. The believer is accordingly the site of a divine presence whose source remains beyond the believer. God’s presence conditions and transforms the believer without becoming dependent upon the believer or reducible to one of the believer’s naturally possessed properties.

This account gives philosophical content to the claim that divine-human union is stronger than mingling but weaker than merger. It is stronger than mingling because the divine presence is not merely adjacent to the believer or externally related to the believer. It is genuinely present within the believer and constitutive of the believer’s new life. It is weaker than merger because the location of the presence does not become its ground. God and the believer remain ontologically distinct even within their union. The finite does not become infinite, nor is the infinite diminished through its presence in the finite. Rather, to borrow Luther’s own language, the infinite is truly in, under, around, and beyond the finite. Finitum capax infiniti: the finite is capable of bearing the infinite precisely because the infinite can be genuinely present within it without ceasing to be infinite.

The formula that emerged from the earlier work can now be stated more precisely: God became a human being while remaining God so that a human being might become God while remaining human. The “while remaining” clauses are not pious qualifications attached after the fact; they identify the ontological structure that any adequate account must preserve. The believer remains human because the believer remains a distinct creaturely substance. God remains God because the divine presence continues to be grounded in God even when genuinely located within the believer.

Christ Lives in Me

Galatians 2:20 provides the paradigmatic expression of this structure: “It is no longer I who live, but Christ who lives in me; and the life I now live in the flesh I live by faith in the Son of God.” The verse neither eliminates the human subject nor leaves that subject unchanged. Paul continues to speak of the life that “I now live in the flesh,” but this continuing human life has received a new ground: “Christ lives in me.” The believer remains the subject who lives, believes, acts, suffers, and hopes; yet the believer no longer understands this life as grounded autonomously in the self.

The non ego, sed Christus is therefore not the destruction of the human “I” but the displacement of its claim to self-grounding. Christ is present in the believer in such a way that the believer’s life becomes genuinely new, while the believer continues to live as a finite human being. The divine presence is not possessed as an achievement or a stable spiritual acquisition. It is received and lived by faith. The believer is constituted by what the believer did not make and cannot own.

Whether the language of the ectopic trope will finally prove adequate remains an open question. Philosophical concepts do not master the realities to which theological language refers, and the success of a model must never be confused with the truth of the reality modeled. Yet theology cannot responsibly affirm that God is genuinely present in the believer while refusing every question about what such presence might mean. The first task of philosophical theology is not to replace confession with metaphysics, but to ask what must be true of reality if the confession itself is true.

The question that first appeared in 1993 was therefore not merely a question about the interpretation of Luther or the historical legitimacy of speaking about theosis. It was a question about the ontology of divine presence. How can the infinite be genuinely present in the finite without absorbing it? How can the finite be transformed by the infinite without becoming infinite? The distinction between location and grounding may offer the beginning of an answer. The believer becomes the home of what the believer does not own, the locus of a presence whose source infinitely exceeds its location. Perhaps this is what it means to say that Christ lives in us while we continue to live our lives in the flesh by faith in the Son of God.

Reality Has the First Word

This essay is part of an ongoing series in philosophical theology from the Department of Philosophical Theology at Christ School of Theology. The series asks some basic but demanding questions: What makes reality intelligible? How does theological language work? What philosophical assumptions support Christian belief? Behind the series is a simple conviction: theology exists because these questions exist. Its first task is to make Christian doctrine intelligible without reducing, replacing, or explaining away the reality to which that doctrine points. 

In the previous essay I suggested that theology did not first become unintelligible because belief in God declined or because secularization advanced. Those developments undoubtedly mattered, but they seem to me to presuppose something still more fundamental. Before theology became difficult, the vocation of seeking the intelligibility of reality had itself begun quietly to disappear. Once reality no longer appeared as something worthy of understanding for its own sake, theology inevitably came to be viewed as one optional conversation among many rather than as a disciplined inquiry into reality under the conditions of God's self-disclosure. 

That diagnosis, however, raises another question. Why should reality ever have seemed worthy of understanding in the first place? What is there about reality that calls human beings into inquiry? 

The modern discussion of knowledge often begins with the knowing subject. We ask about perception, language, conceptual schemes, historical traditions, social practices, and the many conditions under which human knowing takes place. These are indispensable questions. No responsible philosophy can simply ignore the role played by our concepts, our histories, or our linguistic practices in shaping what we know. Yet it is possible to begin in the wrong place even while asking legitimate questions. One begins in the wrong place whenever inquiry is understood primarily as something initiated by ourselves. 

We naturally speak this way. We ask questions. We formulate hypotheses. We devise experiments. We construct theories. The grammar of our language almost invites us to imagine that inquiry originates with us and that reality enters the picture only later as the object toward which our investigations happen to be directed. Increasingly, however, I have come to suspect that this order of explanation reverses the actual structure of inquiry. We do not first decide to investigate reality. Rather, reality first presents itself as something that requires investigation. Before there are questions, there is already something that occasions them. Before there is inquiry, there is already something that has become worthy of inquiry. 

This is perhaps easiest to see when our understanding fails. Reflection seldom begins where everything proceeds according to expectation. It begins when expectations are disappointed. The scientist encounters observations that no longer fit an established theory. The historian discovers documents that refuse to support a familiar narrative. The philosopher finds that an argument once thought compelling now generates contradictions that cannot easily be dismissed. Even in ordinary life we begin to think most seriously when events no longer fit the descriptions by which we had previously organized our world. 

In each case the movement of inquiry is remarkably similar. It is not our curiosity alone that initiates reflection. Rather, something resists us. Reality refuses simply to become what our present descriptions declare it to be. The inadequacy of those descriptions is experienced not merely as an intellectual inconvenience but as an invitation—indeed, almost as an obligation—to understand more deeply. We revise our theories because reality proves richer than the conceptual frameworks by which we first attempted to comprehend it. 

For this reason I have begun to wonder whether inquiry is fundamentally more receptive than creative. This is not to deny the indispensable role of imagination, originality, or theoretical construction. Every genuine advance in human understanding requires them. Yet imagination itself is called forth by something that precedes it. Even our most creative moments remain responses to a reality that has already begun addressing us before we have spoken a single word about it. The scientist does not invent the world she investigates. The historian does not create the past he interprets. The philosopher does not manufacture the logical relations he discovers. In every case inquiry begins because reality has, in one way or another, already presented itself as demanding thought. 

This perhaps explains why earlier generations spoke so naturally of contemplation. The word has become unfamiliar within many contemporary universities, where research is more commonly justified by innovation, productivity, measurable outcomes, or practical usefulness. There is nothing intrinsically objectionable about these concerns. Every civilization rightly values knowledge that heals disease, strengthens institutions, alleviates suffering, or expands technological possibility. The difficulty arises only when usefulness becomes the sole measure of intellectual life. Once that occurs, contemplation inevitably comes to appear idle, because reality itself is no longer regarded as possessing an intrinsic claim upon our understanding. 

Yet the great intellectual traditions of the West were animated by a different conviction. They assumed that reality was not merely available for manipulation but worthy of contemplation. The world was understood to possess an order that invited discovery rather than invention. To devote one's life to understanding that order was therefore not an escape from practical life but one of the highest expressions of it. The university itself was born from that conviction.

If this analysis is correct, then the present crisis of theology is only one manifestation of a much larger cultural development. Theology has become difficult, not simply because belief has weakened, but because we have gradually forgotten the more basic structure of inquiry itself. We have come to imagine that understanding begins with ourselves, when in fact understanding begins by allowing ourselves to be instructed by what is other than ourselves. 

Theology does not overturn this pattern. It radicalizes it. It claims that the deepest reality confronting human inquiry is neither an abstract principle nor an impersonal order but the living God, who addresses the world before the world ever succeeds in speaking truthfully about God. The theologian, no less than the scientist or philosopher, does not possess the first word. Theology begins, as every genuine inquiry begins, by learning to hear a word that has already been spoken.

Why Did We Stop Believing Reality Is Worth Understanding?

This essay is part of an ongoing series in philosophical theology from the Department of Philosophical Theology at Christ School of Theology. 

The series asks some basic but demanding questions: What makes reality intelligible? How does theological language work? What philosophical assumptions support Christian belief?

Behind the series is a simple conviction: theology exists because these questions exist. Its first task is to make Christian doctrine intelligible without reducing, replacing, or explaining away the reality to which that doctrine points.

In the previous essay, I wrote about an afternoon at the Fichte House in Jena. It was not really an essay about history. I was trying, instead, to recover something of the intellectual atmosphere that once made a place like Jena possible.

Fichte, Hegel, Schelling, Schiller, Novalis, and many others disagreed deeply about reality, reason, freedom, and God. But beneath those disagreements was a shared assumption so basic that they rarely felt the need to defend it: reality was worth understanding, and devoting one’s life to that pursuit was among the highest of human callings.

Walking through Jena today, much appears unchanged. It is still a university town. Students still fill the streets and cafés. The institutions remain. Research continues, and knowledge advances at astonishing speed.

And yet it is difficult not to wonder whether something more fundamental has quietly disappeared.

The question is not whether universities still exist. The question is whether they still understand the vocation for which they came into being.

This is not mainly a question about falling enrollment, administrative bureaucracy, or today’s political controversies, important as those issues may be. The deeper question concerns our cultural imagination.

At some point in late modernity, we stopped assuming that reality was worth understanding for its own sake. The pursuit of knowledge increasingly had to justify itself through economic value, technological progress, practical usefulness, or personal fulfillment. Understanding alone no longer seemed like enough of a reason to give one’s life to something.

How did that happen?

There is no single event that explains the change, and it would be too simple to tell a story of uninterrupted decline. The modern world has brought extraordinary advances in science, medicine, technology, and political freedom. It has also taught us important truths about history, culture, language, and the conditions that shape human knowledge.

Still, something has changed in the way educated people imagine the purpose of intellectual life. I suspect that at least three major substitutions have reshaped that imagination.

I. Truth Gave Way to Authenticity

The classical philosophical question was not first, “Who am I?” but “What is true?”

That does not mean earlier thinkers ignored questions of identity, vocation, or selfhood. Augustine and Kierkegaard, among many others, took such questions with utmost seriousness. But they usually placed them within a deeper commitment to reality itself.

Human beings came to understand themselves by learning to inhabit a world they had not made. The self discovered its vocation by participating truthfully in reality, not by turning itself into the measure of reality.

Modern culture has not exactly rejected truth. It has quietly changed the order of priorities.

Authenticity now often occupies the place truth once held. The deepest obligation is no longer understood as conformity to reality, but faithfulness to oneself. An idea may therefore seem persuasive less because it corresponds to its object than because it resonates with personal experience or affirms a particular identity.

This development should not simply be dismissed. It arose for understandable reasons. Modernity rightly became suspicious of authorities that demanded conformity while suppressing individuality. Its recovery of the dignity of the person was a genuine achievement.

But every gain can bring losses with it.

When authenticity gradually replaces truth as the highest intellectual norm, reality begins to recede from the center of inquiry. The self becomes the horizon within which reality is interpreted, rather than reality becoming the horizon within which the self learns to understand itself.

II. Discovery Gave Way to Construction

A second shift followed closely behind the first. Reality came to be described less as something we discover and more as something we construct.

Modern philosophy has done us a great service by reminding us that knowledge is never gained from nowhere. We know through language, concepts, traditions, histories, and particular forms of life. No serious thinker can simply ignore these insights.

The question is whether we have begun to confuse the conditions through which we know reality with the conditions through which reality exists.

That confusion is now common.

It is one thing to say that conceptual frameworks mediate our knowledge of the world. It is another to speak as though those frameworks create the world itself. Reality becomes identified with discourse, narrative, social construction, or linguistic practice. Gradually, the distinction between discovering reality and organizing our descriptions of it begins to disappear.

Ordinary experience, however, keeps resisting this conclusion.

The world disappoints us. Scientific theories must be revised. Carefully built explanations collapse. Reality repeatedly refuses to conform to our descriptions of it.

Language and concepts clearly shape human knowledge. But the world continues to show that it is not simply a product of either one.

III. Contemplation Gave Way to Management

The third substitution may be the easiest to see because it now shapes the university itself.

Knowledge is increasingly expected to justify itself in practical terms. Education is measured by employability. Research is measured by outcomes. Intellectual life is described through the language of efficiency, productivity, innovation, and management.

None of these concerns is illegitimate. A healthy society needs practical knowledge, technical skill, and responsible institutions.

The problem begins when usefulness becomes the only measure that matters.

A civilization that values knowledge only for what it can produce will eventually lose the ability to explain why understanding itself has intrinsic worth.

The great universities of Europe were not founded simply to produce technical expertise. They emerged from the belief that reality itself was worthy of contemplation. Theology, philosophy, mathematics, history, philology, and, later, the natural sciences all shared in that vocation.

Their immediate usefulness was often uncertain. Their dignity rested on something deeper: reality deserved to be understood.

That may be the most important question facing us now.

We often say that theology has become difficult because belief in God has declined or because secularization has advanced. There is truth in both claims. But I increasingly wonder whether they reach the deepest level of the problem.

Before theology became unintelligible, something even more basic had already become unintelligible: the idea that reality itself deserves our understanding.

Once that conviction weakens, theology inevitably begins to look like one optional discourse among many. It no longer appears as a disciplined attempt to understand reality in light of God’s self-disclosure.

The eclipse of theology, then, did not begin when people stopped believing in God.

It began earlier, when we quietly stopped believing that reality was worth understanding.

An Afternoon in the Fichte House in Jena: The Eclipse of Intelligibility

This essay forms part of an ongoing series in philosophical theology produced through the Department of Philosophical Theology at Christ School of Theology. The series explores the conditions of intelligibility, reality, theological language, and the philosophical foundations of Christian belief. It proceeds from the conviction that theology exists because these questions exist and that theology's first responsibility is to render Christian doctrine intelligible without diminishing, translating away, or replacing the reality to which it refers.

Late in May I spent an afternoon in Jena.

Like many university towns, Jena is full of students. Cafés advertise student prices. Young people fill the sidewalks. The university is everywhere. It is a pleasant place, situated in the beautiful countryside of Thuringia, not far from Weimar, where Goethe, Schiller, Herder, and so many others once reflected upon what it meant to become fully human.

But I had not come primarily for Goethe.

I wanted to visit the Fichte House.

Finding it required leaving the main streets and wandering down a quieter side lane until I came upon a modest building that could easily have been overlooked. A man downstairs collected the small admission fee. He seemed genuinely pleased to be there, though I doubted he knew very much about Johann Gottlieb Fichte, the Schlegel brothers, Griesbach, Schelling, or the remarkable constellation of minds that once gathered in that house. None of that mattered. The house itself remained.

I spent nearly three hours there.

During that entire time I saw only one other visitor, a young woman who appeared to have wandered in almost by accident. She slowly walked through the rooms, glanced briefly at the displays, read a few placards, and left perhaps ten minutes later. Toward the end of my visit I heard voices upstairs and discovered what sounded like one of the curators talking with his children about a soccer match. Their conversation was cheerful, ordinary, and entirely disconnected from the world I had entered.

The contrast stayed with me.

Inside those rooms one encountered an intellectual world almost impossible for us to recover imaginatively. Fichte was there. One could almost hear him asking his students, "Gentlemen, think the wall." Then came the second instruction: "Now think about the one thinking the wall."

The point was never the wall. It was the astonishing discovery that what we ordinarily take to be simply "the world" might itself become a philosophical question. If the non-I is known only through the activity of the I, then freedom, knowledge, responsibility, and even history must all be rethought. The Wissenschaftslehre was not an abstract exercise in conceptual ingenuity. It was an attempt to uncover the conditions under which finite rational existence is possible.

The excitement of those years is difficult to exaggerate. Jena at the turn of the nineteenth century was not merely a university town. It was one of those rare places where philosophy, literature, theology, politics, and ordinary life converged around a common conviction: that human beings ought to understand the conditions of their own existence. Fichte, Schelling, Hegel, Friedrich and August Wilhelm Schlegel, Caroline Schlegel, Dorothea Veit, Novalis, Schleiermacher, and Goethe all participated, each in different ways, in the remarkable belief that coming to understand reality was inseparable from becoming more fully human.

Their disagreements were immense. Their shared vocation was greater still.

One sees this perhaps most clearly in Fichte's little book The Vocation of Man. The title itself now sounds strangely foreign. It assumes that human life possesses a vocation and that this vocation is bound up with understanding. One does not simply accumulate information. One comes to know the conditions under which one lives, and in so doing one becomes free. Knowledge was not merely descriptive. It was transformative. One could not understand reality deeply and then simply continue living as before.

Whether Fichte's philosophy ultimately succeeds is beside the point. What matters is that the question itself made sense. It made sense to devote one's life to understanding the deepest conditions of existence because such understanding was believed to disclose what it meant to become genuinely human.

When I finally left the house and stepped back onto the streets of contemporary Jena, I found myself struck less by what I saw than by what I no longer saw. The students hurried past carrying backpacks and laptops. The cafés were busy. The university library was filled with young people working diligently before glowing computer screens. Curious, I wandered into the philosophy section. The shelves remained lined with the great works of German Idealism. Fichte was there. Schelling was there. Hegel was there. They stood patiently where they had always stood, waiting for readers.

Very few appeared interested. Most students were working on spreadsheets, preparing presentations, solving technical problems, or completing assignments in fields Fichte himself could scarcely have imagined. There is, of course, nothing wrong with such work. Every age has its necessary tasks. Yet I could not suppress a question. To come to Jena merely in order to prepare for employment would have been almost unimaginable to those who once made this city famous. They believed that education existed because there was something more fundamental than employment. There was a destiny to human reason. There was a vocation to become intellectually free by coming to understand the conditions under which one thought, acted, and lived.

What struck me most was not that contemporary students no longer shared Fichte's convictions. Cultures change, and questions change with them. What struck me was something subtler. The loss itself no longer appeared to be experienced as a loss. The Fichte House had become a historical curiosity rather than a window into a fundamentally different way of inhabiting the world. The life pursued within those walls had become quaint, almost unintelligible, not because people had carefully considered it and rejected it, but because they could scarcely imagine why anyone would organize an entire life around such questions in the first place.

That realization has remained with me ever since. In recent reflections I have suggested that our culture has largely lost the sense that understanding reality constitutes a genuine human vocation. Standing in the Fichte House, however, I realized something even more unsettling. We have also largely lost the ability to wonder why that vocation has disappeared. The disappearance itself no longer seems puzzling. It has become simply the way things are.

Perhaps that is one of the defining characteristics of late modernity. It is not merely that the vocation of intelligibility has faded. It is that the fading of that vocation no longer appears to require explanation. The students who walked past the Fichte House that afternoon were not making a philosophical mistake. They were living within an intellectual horizon in which the questions that once animated that house had largely ceased to be live possibilities. Their indifference was therefore not something to criticize. It was itself something to understand.

And that, I increasingly suspect, is the philosophical task before us. Before we ask whether Fichte was right or wrong, perhaps we must first ask how it became possible for the world that produced The Vocation of Man to become so thoroughly unintelligible that even its disappearance scarcely invites our curiosity. That question now interests me more than ever.

Why Has It Become Unintelligible to Ask the Question as to Why the Vocation of Intelligibility has Itself Become Unintelligible?

This essay forms part of an ongoing series in philosophical theology produced through the Department of Philosophical Theology at Christ School of Theology. The series explores the conditions of intelligibility, reality, theological language, and the philosophical foundations of Christian belief. It proceeds from the conviction that theology exists because these questions exist and that theology's first responsibility is to render Christian doctrine intelligible without diminishing, translating away, or replacing the reality to which it refers.

In the previous reflection I suggested that Christian theology's contemporary difficulties may not be primarily theological. They may instead reflect something far more comprehensive: a culture in which the very vocation of seeking to understand reality has itself become difficult to recognize as a genuinely human calling. If that suggestion is even approximately correct, however, another question immediately presents itself. How has it become possible for this loss to occur almost unnoticed? Or, stated more precisely, why has it become unintelligible even to ask why the vocation of intelligibility has itself become unintelligible?

The question is easily misunderstood. I am not asking why fewer students major in philosophy, why theology occupies a smaller place within the modern university, or why technology has displaced contemplation as a dominant cultural value. These are important historical developments, and they deserve careful explanation. Yet every historical explanation already presupposes something that I increasingly find remarkable.

Whenever we explain an historical development, we assume that history itself is intelligible. Whenever we offer a genealogy of an idea or an institution, we assume that the genealogy genuinely illuminates what occurred. Whenever we distinguish a better explanation from a worse one, we assume that reality is sufficiently ordered that our explanations can become more or less adequate to it.

The point is not subtle, but it is surprisingly easy to overlook.

Every attempt to explain the eclipse of intelligibility already exercises the very vocation whose eclipse it seeks to explain.

That observation has gradually convinced me that the deepest question before us cannot simply be historical. A genealogy of the disappearance of intelligibility, however illuminating, cannot finally explain the conditions that make genealogy itself possible. Every historical account already presupposes that the past may be truthfully understood. Every explanation already assumes that inquiry itself is capable of yielding genuine understanding. History therefore cannot finally explain the possibility of historical explanation. It can only exercise it.

This has led me to suspect that the phenomenon requiring philosophical attention is not first secularization, modernity, technology, or even theology. It is inquiry itself.

Human beings are remarkable creatures. We do not simply react to our environments. We seek to understand them. We construct interpretations. We formulate hypotheses. We revise judgments that prove inadequate. We compare explanations. We abandon some models while refining others. The scientist does this. The historian does this. The physician, the mechanic, the judge, and the child gradually learning how the world works all participate in the same remarkably familiar activity.

The familiarity of inquiry may explain why we so seldom pause to ask what kind of phenomenon it actually is.

The point is not that inquiry succeeds perfectly. Quite the contrary. We discover its character precisely because our interpretations continually encounter resistance. Reality refuses to accommodate every construction equally well. Some explanations illuminate what confronts us; others gradually reveal their inadequacy. We discover, often reluctantly, that not every way of thinking about the world proves equally capable of making sense of what the world presents to us.

For many years I have found myself returning to Alfred North Whitehead's observation that philosophy, no less than science, advances through the construction of models whose adequacy is continually tested by experience. We imagine possibilities, but reality does not leave every possibility standing. Something constrains our constructions. Some models continue to illuminate the phenomena before us, while others eventually collapse beneath the weight of what they cannot explain. The important point, at least for the present reflection, is not what that constraining "something" ultimately is. The philosophical question comes earlier.

What kind of activity is it that continually seeks more adequate understanding?

This question has become increasingly important to me because I suspect that much contemporary philosophy begins too late. We debate realism and anti-realism, naturalism and theism, idealism and materialism, long before we have adequately reflected upon the phenomenon all of these positions seek to explain. We argue over competing ontologies before asking what sort of activity inquiry itself must be if any ontology is ever to become rationally preferable to another.

Perhaps this is one reason the larger question has become so difficult even to formulate. We have become extraordinarily accomplished at conducting inquiries while rarely inquiring into inquiry itself. We have become skilled at offering explanations while seldom asking what kind of world makes explanation possible. We have become adept at constructing theories while largely neglecting the more fundamental question of what it means for one theory genuinely to illuminate reality more adequately than another.

I increasingly suspect that this neglect is not accidental. It may instead reveal something distinctive about the intellectual horizon within which we now live. We continue to exercise the vocation of intelligibility every day, yet we seldom pause to wonder what kind of phenomenon that vocation actually is. Like breathing, inquiry has become so familiar that it has largely disappeared from view.

Whether this observation proves philosophically fruitful remains to be seen. At present it functions less as a conclusion than as an invitation. Before asking whether reality is ultimately material or spiritual, finite or infinite, personal or impersonal, perhaps we should first ask a simpler question. What are we doing when we genuinely seek to understand anything at all?

The more I reflect upon that question, the more I suspect that it may be one of the most neglected philosophical questions of our time.