Disputation XXX: De Veritate Interna et Externa Theologiae

On Internal and External Truth in Theology

Utrum veritas theologiae sit tantum interna in suo sermone, an etiam externa in relatione ad ipsum Deum, ita ut sermo theologicus non solum sit fidelis in se, sed etiam verus de eo quod est.

It is asked whether the truth of theology is only internal to its own discourse, or also external in its relation to God himself, so that theological language is not only faithful in itself but also true of what is.

__________

Thesis

Theology possesses a twofold truth: internal and external. Veritas interna is the felicity of discourse authorized by the Holy Spirit within the community of faith; it is the truth of theology intra systema fidei. Veritas externa is the adequation of this discourse to divine reality: the truth of theology de Deo ipso.

The former concerns the integrity of theological grammar; the latter, the participation of that grammar in the infinite Word. The two are not opposed but ordered: the Spirit authorizes language internally so that it may participate externally in the Logos.

Formally expressed:

$$\text{<i>Auth</i>}<i>(</i>{\mathrm{<i>L</i>}}_{\mathrm{<i>t</i>}}<i>)</i><i>\Rightarrow </i>\mathrm{<i>\exists </i>}\mathrm{<i>I</i>}<i>:</i>{\mathrm{<i>L</i>}}_{\mathrm{<i>t</i>}}<i>\hookrightarrow </i>{\mathrm{<i>L</i>}}_{\mathrm{<i>\infty </i>}}$$

This states that theological truth obtains only if the Spirit establishes an interpretive inclusion of the finite theological language $L_t$ into the infinite divine discourse $L_{\mathrm{\infty }}$. This symbol (↪) indicates participatory inclusion, not the formal subset relation. It is the Spirit’s act by which finite discourse is gathered into infinite meaning.

Locus Classicus

“I am the way, and the truth, and the life.” — John 14:6

In this declaration, Christ identifies truth not as correspondence or coherence, but as personal participation in the divine Logos. Augustine reads this as meaning that “veritas non est aliquid extra Deum, sed ipse Deus veritas est” (De TrinitateVIII.4). Aquinas echoes: “Veritas est adaequatio intellectus et rei; in Deo autem idem est intellectus et res” (ST I.16.5). Therefore, for theology, truth cannot be merely formal, but it must be participatory. The finite intellect is true only insofar as it shares in the divine act of knowing.

Explicatio

In the history of thought, the distinction between truth within a system and truth about a system first appears formally in model theory. A sentence φ is true in a structure M if it is satisfied by the interpretation within that model. However, the claim that M is a true description of reality belongs to a meta-level statement.

Analogously, theology’s internal truth corresponds to felicity within its Spirit-constituted framework. While the Church’s speech is true in fide, when it coheres with the rule of faith and manifests the Spirit’s authorization, its external truth pertains to whether this discourse participates in divine reality, whether it corresponds to what God is.

Modern theology, following Kant and linguistic turns, has often reduced truth to the internal. For example, Barth restricted it to divine self-revelation, Lindbeck to communal grammar, and postmodern theology to local language-games. Yet each of these, by refusing externality, confines truth to the system and renders theology self-referential.

Against this, classical realism affirmed that the Word of God not only structures faith internally but also grounds reality externally. The Word that words is the same Word through whom the world worlds. Hence theology’s truth is not self-enclosed but world-constituting; it participates in the divine Logos that both gathers thought and gives being.

While the Spirit grants felicity—right utterance, coherence, confession—the Son grants truth—ontological adequation. The Incarnation unites both: the Word made flesh is veritas interna (Spirit-born confession) and veritas externa (divine reality) made one.

Thus, just as in logic the meta-system grounds the internal system’s truth, so in theology the infinite Word grounds the discourse of the finite. The Spirit mediates this inclusion, making the finite participate in the infinite, so that theology may speak truly both in and of God.

Obiectiones

Obj. I. Empiricism claims that all truth must be verifiable by observation. Theological claims are unverifiable and thus have no external truth. There is only the internal coherence of theological discourse for believers using it. 

Obj. II. From the cultural-linguistic standpoint, theology’s meaning arises only within the communal grammar of faith. Thus, to speak of “external truth” misunderstands language as representational rather than formative. Theology is true insofar as it performs its grammar.

Obj. III. Post-modernity assumes that every discourse is self-referential such that “outside” a language game there is nothing. Hence “external truth” is a non-starter. All truth is internal to interpretation.

Obj. IV. Barthians held that God’s revelation is self-grounded and free, and that appeal to participation or adequation cannot verify it. Truth exists only in the event of revelation, it is not tied to ontology.

Obj. V. Contemporary analytic thinking holds that model-theoretic analogies fail for theology. There is no definable model of God; hence talk of inclusion Lt​↪L∞​ is metaphorical and lacks formal content.

Responsiones

Ad I. Verificationism mistakes the order of reality for the order of appearance. Theology is not an empirical but a participatory science: it knows by union, not by observation. External truth in theology is not sensory correspondence but ontological inclusion in the act of God.

Ad II. The Church’s grammar is indeed formative, yet its form is the Spirit’s work, not a human construct. The Spirit’s authorship makes the grammar porous to transcendence; hence, its truth cannot be merely communal but is grounded in the divine speech that precedes the Church.

Ad III. Postmodern closure presupposes the very transcendence it denies. The internal system’s finitude points beyond itself to the infinite that constitutes it, just as, by the Löwenheim–Skolem principle, any consistent system admits higher interpretations. The finite theological discourse testifies by its very limitation to the necessity of the divine meta-language.

Ad IV. Revelation is not opposed to participation but presupposes it. God’s free act of self-disclosure is the mode in which creatures participate in divine truth. To say revelation alone grounds truth is already to affirm that truth has external reality in Deo ipso.

Ad V. While theology cannot construct a formal model of God, the analogy holds analogically: God is the modelus sui sermonis, the reality to which divine discourse is perfectly adequate. Finite theology participates in that adequation by the Spirit. Thus, the inclusion ${\mathrm{<br>}}_{}$ is not formal but real: it signifies the Spirit’s act of joining human speech to the eternal Word.

DETERMINATIO

From the foregoing it is determined that:

1. Veritas interna is the pneumatological authorization of theological discourse, its faithfulness, coherence, and integrity within the Spirit’s grammar.

2. Veritas externa is the Christological participation of that discourse in the divine Logos, the ontological adequation by which the Word that words also constitutes what is.

3. The two are ordered: the Spirit perfects language internally so that it may correspond externally to the Word.

4. Finite discourse, like a logical system, cannot ground its own truth; it requires inclusion in the infinite speech of God.

5. Therefore, theological truth is neither merely communal nor purely propositional but participatory, It is rather the inclusion of finite utterance in infinite meaning.

Hence we conclude: Veritas interna sine externa est infidelis; veritas externa sine interna est muta. Only when the Spirit authorizes and the Logos fulfills does theology speak the truth.

Postscriptum Modernum

Gödel’s incompleteness theorems and the Löwenheim–Skolem results together illuminate the formal necessity of theological participation.
Gödel showed that any sufficiently rich, consistent formal system contains truths that cannot be proven within it; there are statements true in the system but not demonstrable by it. The Löwenheim–Skolem theorems, conversely, reveal that no formal language uniquely determines its own model, foeeven first-order theories with infinite models admit both smaller and larger interpretations.

Taken together, these findings expose a deep structural fact: no finite system can secure its own truth. Consistency does not entail completeness and satisfaction within does not entail adequation without. Hence, every coherent finite language gestures beyond itself toward a meta-language or an infinite frame in which its truth is grounded.

Theology mirrors this logic. The finite L_t of human discourse may be internally consistent—Spiritually felicitous—but its truth as about God depends upon participation in the infinite L_∞ of the divine Logos. The incompleteness of reason is not its defect but its vocation: it is the mark of the finite’s openness to the Infinite.

Thus, what logic demonstrates negatively—that no system can prove itself complete—theology confesses positively: Finite speech becomes true only when the Word that words gathers it into the world that worlds. In this gathering, internal felicity becomes external truth; the Spirit’s authorization becomes the Logos’s fulfillment.