Disputatio XLV: De Bello inter Necessarium et Contingens in Ratione Finita

On the Conflict Between the Necessary and the Contingent in Finite Reason

Quaeritur

Utrum in ratione finita oriatur verum bellum inter necessarium et contingens, ita ut ipsa mens humana, participans quidem rationem divinam sed limitata in tempore et potentia, neque ordinem necessitatis neque veritatem contingentiae plene conciliare possit; et utrum haec pugna sit defectus cognitionis aut potius signum participationis creaturae in divina sapientia, quae in se unam facit necessitatem et libertatem.

Whether within finite reason there arises a true conflict between the necessary and the contingent—such that the human mind, participating in divine reason yet limited in time and power, can fully reconcile neither the order of necessity nor the truth of contingency—and whether this struggle is a defect of knowledge or rather the sign of the creature’s participation in divine wisdom, in which necessity and freedom are one.

Thesis

Finite reason stands at war within itself. It is drawn upward toward necessity—the demand that all things have sufficient reason—and outward toward contingency: the recognition that the world could have been otherwise. These two poles define reason’s created condition: necessity as the mark of its participation in divine intelligibility, contingency as the sign of its existence within temporal becoming. The conflict between them is not accidental but constitutive; it reveals that reason is a mirror of divine unity seen through the prism of finitude. Only participation in divine reason can reconcile this struggle, for in God necessity and freedom coincide as one act of infinite love.

Locus classicus

Aristoteles, Metaphysica XII.7 (1072b):

Ἔστιν ἄρα τι ὃ οὐ κινούμενον κινεῖ, ἀΐδιον καὶ οὐσία καὶ ἐνέργεια.
"There is therefore something which moves without being moved, being eternal, substance, and actuality." 

Necessity here grounds all motion and explanation, yet Aristotle leaves contingency as the realm of the changeable.

Thomas Aquinas, Summa Theologiae I, q.14, a.13:

Deus cognoscit contingentia ut contingentia, et tamen infallibiliter.
"God knows contingents as contingents, yet infallibly."

Aquinas thus binds the necessity of divine knowledge with the contingency of creaturely events.

G. W. Leibniz, Monadologie §31:

Le présent est gros de l’avenir; le futur peut être lu dans le passé.
"The present is pregnant with the future; the future may be read in the past." 

Leibniz unites necessity and contingency by grounding both in divine reason’s selection among possibles.

Immanuel Kant, Kritik der reinen Vernunft (A536/B564):

Die Antinomie der Freiheit und der Naturnotwendigkeit ist der Schlüssel zur ganzen Dialektik der reinen Vernunft.
"The antinomy of freedom and natural necessity is the key to the entire dialectic of pure reason." 

Finite reason must affirm both necessity and freedom, though it cannot conceptually reconcile them.

Paulus Apostolus, Epistola ad Romanos 11:33:

Ὦ βάθος πλούτου καὶ σοφίας καὶ γνώσεως Θεοῦ· ὡς ἀνεξερεύνητα τὰ κρίματα αὐτοῦ καὶ ἀνεξιχνίαστοι αἱ ὁδοὶ αὐτοῦ.
"O the depth of the riches both of the wisdom and knowledge of God! How unsearchable are His judgments and His ways past finding out!" 

Here Scripture gathers the philosophical tension into doxology: the irreconcilable in reason is peace in God.

Explicatio

The Principle of Sufficient Reason demands that nothing exist without ground. Yet our lived and empirical world continually presents us with events that appear ungrounded—acts of freedom, emergence, chance, and history. The human intellect thus finds itself divided: it cannot deny contingency without denying experience, nor affirm it without weakening reason’s own axiom.

This division is not an epistemic defect but a metaphysical condition. The creaturely intellect, as ratio finita, participates in eternal reason while operating within time. Its demand for necessity mirrors the divine order of wisdom; its experience of contingency mirrors the divine act of freedom. Their conflict is the creature’s mode of imaging the divine simplicity.

Philosophically, the battle has appeared as determinism versus freedom, logic versus history, metaphysics versus phenomenology. Spinoza’s monistic necessity, Hume’s skeptical contingency, and Kant’s transcendental antinomy each represent one side of reason turning against the other. Theologically, the conflict mirrors the drama of creation: God’s will is necessary in its goodness but free in its expression; the world, therefore, bears both the mark of rational necessity and the gift of contingent grace.

From a model-theoretic perspective, this conflict corresponds to the difference between syntactic necessity—the closure of reason within its own laws—and semantic openness—the reference of those laws to realities beyond themselves. Finite reason, like a theory without a complete model, cannot guarantee within itself the harmony of necessity and freedom. It points beyond itself to divine intellect as the infinite model that alone reconciles law and event, order and surprise, necessity and grace.

Objectiones

Ob. I. If necessity and contingency conflict in reason, reason ceases to be the image of God, for divine wisdom is pure harmony, not opposition.

Ob. II. The war of reason dissolves the certainty of knowledge. Science depends on necessity; freedom introduces indeterminacy and undermines causality.

Ob. III. In God all things are necessary. To admit contingency as real is to multiply being unnecessarily and to posit irrationality in creation.

Ob. IV. If divine simplicity is reflected analogically in reason, conflict cannot belong to its essence but only to sin or ignorance.

Ob. V. Freedom and necessity are mutually exclusive modes; to unite them is to destroy both. Freedom requires absence of constraint; necessity implies total determination.

Responsiones

Ad I. Reason’s conflict is not an imperfection but a sign of participation. The image of divine unity cannot be mirrored as unity within limitation; it must appear as tension. The created intellect is peace refracted through time.

Ad II. Scientific necessity and existential contingency belong to different orders. Within the order of nature, necessity prevails; within the order of personhood and grace, contingency testifies to divine freedom. Their apparent discord arises only when the orders are confused.

Ad III. Contingency is not absence of reason but expression of rational plenitude. God’s necessity includes contingency as the free manifestation of His wisdom. Creation’s freedom is the outward face of divine necessity, not its negation.

Ad IV. Sin and ignorance distort but do not create the conflict. Even in an unfallen world, reason would still know both the fixed wisdom of God and the open mystery of His will. The cross, not sin, is its deepest image: the union of divine necessity and contingent suffering.

Ad V. Freedom and necessity are contraries only within finite categories. In God they coincide: necessity is freedom fully realized, freedom is necessity made gracious. Their distinction arises when divine simplicity is viewed from within time.

Nota

The human intellect is suspended between necessity and freedom as between heaven and earth. It is drawn to explain all things by law yet confronted daily by the contingency of event, love, and decision. This tension is not to be overcome but understood as the very structure of participation. The Logos grounds necessity; the Spirit breathes contingency; together they make finite reason a theater of divine wisdom.

In Christ, this war reaches its peace: the eternal necessity of divine being enters the most contingent of all moments—the suffering of a particular man. There necessity becomes merciful and contingency redemptive. Thus, the bellum inter necessarium et contingens is resolved only in the cruciform logic of the Word made flesh, where infinite reason inhabits finite circumstance.

Determinatio

1. The conflict between necessity and contingency belongs intrinsically to finite reason and is the mark of its dependence on a higher unity.

2. Necessity reflects participation in divine wisdom; contingency reflects participation in divine freedom. Both are analogical to the single act of God.

3. Human reason cannot reconcile the two dialectically but only through participation in divine reason, where wisdom and will are one.

4. The cross is the metaphysical symbol of this reconciliation: the necessary will of love embracing contingent suffering, revealing that the ultimate law of reason is grace.

Transitus ad Disputationem XLVI: De Possibilitate ut Medio inter Necessarium et Contingens

The battle between necessity and contingency cannot end within finite reason, for each side speaks a truth it cannot deny. Necessity grounds intelligibility; contingency preserves freedom. Yet their reconciliation demands a third term, one that holds both without confusion or separation. That term is possibility.

Possibility is the quiet field in which this war becomes intelligible. It is neither necessity itself nor mere contingency, but the horizon within which both arise. For something can be contingent only if it is possible, and it can be necessary only if its possibility is immutable. Possibility thus mediates between the fixity of being and the openness of becoming. It is the form of divine generosity within reason—the locus where wisdom and will meet.

In the divine intellect, all things are possible before they are actual. God wills not arbitrary freedom but the necessary possibility of all that could exist in Him. The world’s contingency, therefore, rests upon the eternal stability of possibility within God’s reason. Finite reason, when it perceives this, finds the first light of reconciliation: the necessity of the possible unites the freedom of the actual.

The next disputation will therefore inquire De Possibilitate ut Medio inter Necessarium et Contingens. It will show that possibility is not a neutral category of modality but a theological reality: the mirror of divine potency and wisdom, and the foundation of all rational hope. For what is possible in God is already real in truth, and what becomes actual in creation is the contingent expression of that necessary possibility.

Disputatio XLIV: De Contingentia Creationis et Libero Arbitrio Divino

On the Contingency of Creation and Divine Freedom

Quaeritur

Utrum libertas divina consistat non in arbitrio indifferenti sed in plenitudine rationis, qua Deus necessario vult se ipsum et contingenter manifestat se in creatione; et utrum haec contingentia creationis intellegi possit modalis ratione, ita ut creatio sit necessario possibilis in Deo, licet non necessario actualis.

Whether divine freedom consists not in arbitrary indifference but in the fullness of reason, by which God necessarily wills Himself and contingently manifests Himself in creation; and whether this contingency of creation may be understood modally, such that creation is necessarily possible in God, though not necessarily actual.

Thesis

Divine freedom is the rational plenitude of the necessary Good. God’s will is not arbitrary but coincides with divine wisdom: Deus vult se necessario, alia a se contingenter. Creation is not an irrational possibility but the intelligible unfolding of divine necessity in contingent form.

In modal terms:

• God’s existence: □G.

• Creation’s possibility: □(G → ◊C).

• Creation’s actuality: ◊C ∧ ¬□C.

Thus, the necessity of possibility in God grounds the possibility of contingency in creation. The Spirit mediates this order, actualizing the possible through love.

Locus Classicus

Thomas Aquinas, Summa Theologiae I, q.19, a.3:

Deus necessario vult se, sed non necessario vult alia a se.
“God necessarily wills Himself, but not necessarily the things other than Himself.”

Leibniz, Essais de Théodicée, §173:

La liberté divine consiste dans le choix du meilleur.
“Divine freedom consists in the choice of the best.”

C. S. Lewis, Mere Christianity (1952):

God created the universe freely, not because He needed it, but because He is love.

Modal Maxim (S5):

□p → ◊p, and ◊□p → □p.

The theological implication: what is necessarily possible in  God is immutably intelligible even if contingently realized.

Explicatio

From the perspective of modal metaphysics, divine freedom can only be conceived as the perfect coincidence of necessity and rationality. The act of creation does not introduce irrational novelty into God but manifests eternally possible forms (rationes aeternae) through the free act of love.

In S5 logic, the following distinctions hold:

1. Divine Necessity (□G): God’s existence and essence are necessary. There is no world in which God does not exist: ¬◊¬G.

2. Necessary Possibility of Creation (□◊C): Because God is necessary, creation is necessarily possible: □(G → ◊C). This expresses the eternal availability of creaturely being within divine reason.

3. Contingent Actuality of Creation (◊C ∧ ¬□C): Creation is possible but not necessary. Its existence is not required by divine nature but freely willed: G → ◊C, not G → □C.

4. Modal Principle (MT): □G → □(∀p (◊p → ◊(G → p))). If God exists necessarily, then every possibility is necessarily possible through Him.

Hence, divine freedom may be defined as the actualization of one among necessarily possible worlds according to the order of divine wisdom and goodness. Creation is contingent not because it lacks sufficient reason, but because its reason is of the mode of love, not necessity.

The freedom of God is not voluntas indifferens—a will suspended among options without reason—but voluntas sapientiae: the necessary self-diffusion of goodness. God could have willed otherwise (◊¬C), but what He does will, He wills wisely (□(G → R(C))).

The creature’s contingency thus arises from the necessity of possibility, the divine act that grounds modal being itself. The Spiritus Intelligentiae mediates between the eternal intelligibility of possibility in God and its temporal realization in the world.

Objectiones

Ob. I. Spinoza holds that if God necessarily exists and acts according to His nature, then everything He does is necessary. The very notion of contingency implies imperfection or external limitation, both impossible in God.

Ob. II. van Inwagen claims that to preserve divine freedom, one must deny any determining reason for God’s act of creation. If God has a reason to create this world rather than another, His act is no longer free but necessitated.

Ob. III. For Kant, the idea of divine freedom as “choice among possible worlds” is anthropomorphic. The notion of modality applies only within phenomena; we cannot ascribe modal distinctions to noumenal divinity.

Ob. IV. Existentialism argues that freedom entails the capacity to act without ground. If divine freedom has a sufficient reason, it ceases to be freedom.

Ob. V. Theological voluntarism argues that God’s will precedes His reason. To say that God wills according to wisdom subordinates will to intellect and thus compromises divine omnipotence.

Responsiones

Ad I. Spinoza confuses necessity of essence with necessity of act. God necessarily exists and knows Himself, but His creative act proceeds freely from wisdom, not from causal compulsion. Necessity in God does not exclude contingency in effects; it grounds it as rationally possible.

Ad II. Freedom does not require absence of reason but rational self-determination. The act of creation is free because it proceeds from perfect knowledge, not from external constraint. To remove reason from freedom is to render it arbitrary and unintelligible.

Ad III. Kant’s epistemic modesty cannot constrain ontology. If divine reality grounds all possibility, then modal categories originate in the divine intellect, not in human cognition. God is the ens modalitatis—the cause of the possible as such.

Ad IV. Existential freedom, detached from reason, is negation, not creativity. True freedom is fecund: it gives being. God’s freedom is plenitude of intelligibility, not indeterminate spontaneity.

Ad V. Divine will and intellect are one act in God. The will is rational and the intellect volitional. To will otherwise than wisdom dictates would be impotence, not omnipotence.

Nota

The modal order of creation is rooted in the divine act itself. The necessity of possibility (□◊C) safeguards both divine aseity and creaturely contingency. God is the ground of all modal truth: possibility, actuality, and necessity are modes of participation in His being.

Creation’s contingency is thus not a failure of reason but its richest expression. It reveals that divine necessity is not sterile self-enclosure but communicative plenitude. In the contingent, the necessary becomes gracious.

Hence, contingency is the modality of divine generosity. The Logos grounds it; the Spirit enacts it; and love interprets it.

Determinatio

1. God necessarily exists: □G.

2. Creation is necessarily possible through God: □(G → ◊C).

3. Creation is contingently actual: ◊C ∧ ¬□C.

4. Divine freedom is the rational actualization of a necessarily possible world:
   □G ∧ ◊C → (□(G → R(C)) ∧ ¬□C).

5. Contingency is not absence of reason but finite manifestation of infinite rationality.

6. The Spirit mediates between modal being and actual creation, so that what is eternally possible becomes temporally real.

7. Therefore, contingency is intelligibility-in-gift, with the world being the rational outpouring of necessary love.

Transitus ad Disputationem XLV: De Bello inter Necessarium et Contingens in Ratione Finita

Having seen that divine freedom is the plenitude of rational necessity and that creation’s contingency arises from the necessity of possibility, we must now consider how this relation appears within the finite intellect.

For the human mind experiences a conflict: it perceives necessity as threat to freedom and contingency as threat to reason. This interior bellum within ratio finita mirrors, in fractured form, the divine harmony of wisdom and will. It is here that metaphysical participation becomes phenomenological struggle.

We therefore proceed to Disputationem XLV: De Bello inter Necessarium et Contingens in Ratione Finita, where it will be asked how finite reason, torn between the poles of necessity and freedom, may find reconciliation through the Logos crucified—the Wisdom in whom all opposites are made one.

The Logic of Transcendental Logic

Immanuel Kant employs transcendental logic to show that the synthesis involved in judging that the conceptual "presentation" (Vorstellung) P applying to the conceptual "presentation" (Vorstellung) S also applies to intuitional presentations (Vorstellungen). In other words, the syntheses involved in the act of judgment in general ultimately make possible the world of our experience, a world in which we know objects. 

According to Kant, while general logic abstracts from the particular content of concepts related, concentrating instead on the formal features involved in relating the concepts, transcendental logic deals with the most general features of our experience of objects in space and time.  Unlike general logic, transcendental logic is not about the capacity for thinking as such, but concerns itself with our thinking in relation to our experience of objects as such.  Accordingly, transcendental logic deals with rules of synthesis in so far as this synthesis applies to intuitions as well as to concepts.  It is left to Kant's transcendental deduction to show that the necessary condition for the possibility of experience as such is that there exists a transcendental unity of apperception, an "I think" that is presupposed in all activity of knowing objects.  

Kant famously offers a transcendental deduction in the first edition of the Critique -- the "A deduction" -- which he completely rewrites in the second edition six years later -- the "B deduction." There is a pronounced difference in emphasis between the two deductions with the first being predominantly a "subjective deduction" while the second attempts an "objective deduction."  

The precise contour of the transcendental arguments are a matter of considerable debate, but one might broadly paint the  "B deduction" as follows: 

• Our experience is one of a succession of awarenesses, that is, a succession of contents of consciousness.

• The condition for a succession of awarenesses, however, is an awareness of the succession itself, that is, the successive contents of consciousness must be combined and held together in a unity of consciousness. Such a unity is a necessary condition for an experience of succession. 

• For this synthesis to be presented (represented), I must think it. 

• But this analytic unity of the self thinking its objects presupposes a synthetic unity of the manifold.  In other words, presupposed is a transcendental unity of apperception, a unity of the "I think" that is neither the empirical "self" of psychology, nor a metaphysical thinking substance a la Descartes. (The "I" could never know itself if it were not possible to unify the manifold through synthesis.)

• The transcendental unity of apperception is an objective, not a subjective, unity.  The conditions for this unity are the conditions by which we have consciousness of objects in general. 

• An object is that under the concept of which the manifold is united.  The necessary conditions for uniting the manifold is a unity of consciousness, a unity that bestows objective affinity to transcendental apperception.  

• Since there is an objective unity in the transcendental unity of apperception, the synthesis must proceed according to the categories and the rules required for experience as such.  

My aim in this brief blog post is not, however, to discuss the differences between the deductions, nor to talk about the differing views on the structure of the deductions within the voluminous secondary literature seeking to understand them. Rather I want to highlight the general modal features of transcendental arguments. I am not the first to do this, of course, but sometimes people reading Kant miss the forest for the trees. Sometimes people simply forget to mention that Kant is engaged in a modal argument of a particular kind.  Let us look at the logical structure of Kant's transcendental argument. 

Kant is interested in the necessary conditions for the possibility of experience as such.  Clearly, the argument is difficult to state if we do not include its modal features.  So what is the argument structure, when these are included? 

• Premise I:  There is the possibility of experience as such.  Using Polish notation of L for the necessity operation and M for the possibility operator, we might say 'Me', experience is possible.  

• Premise II:  It is necessary that, if experience is possible, then there exist conditions C for that experience.   We might express this as 'L, if Me, then o'.  (I am using 'o' for 'conditions'.) 

• Conclusion: Lo. 

Kant is claiming that from the mere possibility of experience we can conclude to some necessary features making possible that experience.  He is not arguing that as a matter of contingent fact some conditions (or other) obtain -- that is, empirical conditions -- that would account for that experience.  He is saying that in each and every possible world, the same conditions C must obtain, if there is a possible world where experience E is had.   

Those familiar with modal logic will understand that Kant is presupposing Lewis' S5 in order to conclude to the necessity of C.  Let us review basic modal systems briefly. 

• We might have a system that might allow us to move from necessity to possibility.  Using Polish notation, we have the distinguishing axiom 'CLpMp', if p is necessary, then p is possible.  (Read the 'C' as the conditional 'if, then', e.g., 'if Lp, then Mp'.) That is, if p obtains in all possible worlds, p obtains in some possible world.  (It is hard to conceive how something appearing in all possible world is not possible, for it is in every world that is, by definition, possible.)

• We could add to this first system another axiom this one from actuality to possibility: 'CpMp', if p obtains then p is possible.  That is to say, if p obtains in the actual world, then p obtains in a possible world.  (This seems plausible since the actual world is a possible world.)

• We can add to this second system another plausible theorem: 'CMMpMp'. We have now arrived at Lewis' system S4 holding that if something is possibly possible, then it is possible.  In other words, if p is possible in a possible world, then p is itself in a possible world.  (This seems plausible since all there are are possible worlds, and it would be strange were something possible in a possible world to somehow not simply be possible.) 

• Finally, we get to S5, sometimes assumed to be the "standard" system of model logic.  This system is generated from 'CLpMp', 'CpMp', CMMpMp' and the distinguishing assumptions of S5, 'CMLpLp', that is, if it is possible that something is necessary, then it is necessary.  Simply put, if there is possible world where some necessity holds, then, since for something to be necessary it obtains in all possible worlds, that which is necessary in that possible world is now ingredient in every possible world. (It is hard to see what being necessary in a possible world might be, if that necessity does not extend over all possible worlds.)  

Those familiar with ontological arguments for the existence of God should immediately recognize the importance of S5. Assume it is possible that God exists. Now reflect on the nature of God. Is God the kind of being that could exist contingently like a rat or an apple, or is God the king of being who, were God to exist, would exist necessarily?  If one's intuitions are of the latter, then God either exists in all possible worlds or in no possible worlds. But how do we know?  We know by checking whether or not God's existence involves a self-contradiction.  If God's existence is self-contradictory, then God does not exist in a single possible world. However, if God's existence is not self-contradictory and God's existence is not contingent, then the very possibility of God existing entails that God exists in all possible worlds including the actual world!  

So how do we apply S5 here?  Let us look at the argument again, and see if we can arrive at the conclusion. 

• Premise I: Me

• Premise II: LCMeo   (This says that necessarily, if possibly e then o.)

• S5 Assumption: CMLpLp

• But (2) is logically equivalent in all modal systems to 'CLMeLo'

•  From(3), 'C~Lp~MLp'. 

• (5) is equivalent to 'CM~pLM~p'. 

• Substituting 'e' for '~p' uniformly, we get, 'CMeLMe'. 

• Thus from (1), we derive 'LMe'. 

• Now by (4) through modus ponens we get 'Lo', and thus 'o' constituted necessary conditions for the possibility of 'e'.  QED. 

It is not immediately apparent what is wrong with this proof. Kant is engaged in critical or immanent metaphysics in the Critique. He is not talking about his believing or knowing primarily, but those states of affairs making true his believing and necessary for his knowing. The transcendental unity of apperception constitutes a necessary condition for any possible experience, that is to say, if there is a world in which there is experience 'e', then there can be no worlds in which transcendental unity fails to obtain.  The very possibility of 'e' entails the necessity of 'o'.  

Now the question of the claim: Is Kant really trying to say that 'o' obtains in all worlds, or simply that there is no world having 'e' that does not have 'o'? Are we saying that worlds in which 'e' does not obtain have 'o'?  In other words, are we asserting a necessity of consequence or a necessity of the thing consequent.  

In the medieval tradition God's foreknowledge was figured as a necessity of consequence, not a necessity of the thing consequent.  If God foreknows that S rejects God, does God's foreknowledge itself logically entail S cannot reject God? The solution was to discriminate the scope of the modal operator.  In worlds in which God foreknows S rejects God, S cannot not reject God.  However, in worlds where God does not have this foreknowledge, then S is presumably not logically determined to reject or not reject.  Are we saying that the transcendental argument is more like a necessity of consequence: In worlds were 'e' occurs, it cannot be that 'o' fails to obtain.  But how about those worlds in which 'e' does not transpire?  Must 'o' be ingredient in them as well?  And if 'o' is not ingredient, then how must we adjust the transcendental argument?  Clearly, these questions motivate a deeper investigation.