The Medieval Mind of CS Lewis

One’s normal reaction to a new book about C.S. Lewis is probably the same as a new book on John Calvin or the Five Points of Calvinism: “Not another one.”  Jason Baxter’s book, however, has new material. Beginning with Michael Ward’s book on the planets and Narnia, theologians have realized that Lewis’s understanding of the heavenly spheres was more than just metaphorical.  He had the exact same outlook as the medieval writers.  We thank Jason Baxter for that insight.

Baxter sees Lewis as “Becoming Boethius.”  Like the early medieval figure, Lewis bridged the gap between the Christian medieval world, especially prior to Aquinas, and our own time. But if Lewis is going to be Boethius, and if we are going to see what such a mind looks like, we have to see how the medieval mind viewed the planets. The planets provided man with a “harmony of the spheres.”  The world and the planets were arranged in a musical interval.  Here Baxter does an extended analysis of scenes in Lewis’s The Discarded Image.[1] It looks like this:


Primum Mobile, which causes the stellatum to move. The stellatum then move Saturn.

Saturn, for Dante at least, is the heaven of contemplatives. More commonly, though, he is Father Time.

Jupiter is the king.

Mars is iron-like.

Sol, or Sun.



In the Christian era, these heavens were associated with angels.  However, Lewis points out that the danger to monotheism “clearly came not from a cult of angels but from the cult of the Saints. Men when they prayed were not usually thinking of hierarchies and intelligences.”[2]

This extended detour serves to illustrate a point Baxter makes later. With the current talk about a disenchanted universe, one might be surprised to hear the disenchantment in the heavens.  No longer could the heavens be seen as a harmonic prove of Platonic solids.  That probably does not bother us like it would earlier ages.

Breathing Narnian Air

This was a fun chapter. Why do people resonate with Lewis’s works so much?  They do because Lewis enables them to experience what “an idea felt like.”  You feel the idea of Goodness. You can probably think back to a book where you had this experience.  For me it would have been Spenser’s Faerie Queene or the scene with Mr. Valiant-for-Truth in Pilgrim’s Progress.  In other words, you can “breathe the atmosphere of a story.”

There is a deeper philosophical issue at play as well.  For it we again turn to Boethius.  Humans normally know something via ratio, or discursive judgment. Every now and then, though, when hit with a powerful idea, we know via intellectus, or through actual intelligence.  This is more intuitive.  This is what Lewis meant in his famous essay about “looking along a beam of light.” When you look alongside a beam of light in a dark shed, your eyes are directed towards the opening and then you see much, much more.


I recommend this work to more advanced students of Lewis.  Baxter also deals with Till We Have Faces and mysticism, both good and bad, so Lewis argues, in Letters to Malcom.

[1] C. S. Lewis, The Discarded Image, (New York: Cambridge University Press, 1964), 102ff.

[2] Lewis, Ibid, 120.

Muller notes on Divine Will, part 2; Aristotle and Aquinas


Aristotle and Aquinas

Main idea: Aristotle never set aside the principle of bivalence but instead presumed a distinction between “definitely true” and “indefinitely true” propositions (88).  A human being can have opposing potencies, and even when one is actualized, the contrary potency doesn’t disappear but remains as a potency.

The Medieval Reception

It isn’t simply “either we are free or God knows everything.”  Rather, as Augustine pointed out, there is an “order of causes in which the highest efficiency is attributed to the will of God” (Civ. Dei 5.9).


Let’s take the statement, what will be tomorrow is necessary.  The medievals understood this statement to be mean: “Whatever is, when it is, cannot be in the same moment other than what it is” (Muller 107). To anticipate later discussions, while the future may not be “up for grabs” from God’s point of view, it is nevertheless contingent.

There is also a distinction between necessity and certainty.  Necessity is lodged in the thing known and certainty in the knower.


Aquinas held that not all effects have necessary causes.  Aquinas maintained free choice by saying rational beings have the potency to more than one effect.  We have a simultaneity of potencies (SCG III.72).

Aquinas and Divine Power.

Muller then discusses the standard distinction of absolute vs. ordained power. This undergirds how God is said to relate to the world, and the world order itself is contingent result of God’s free willing (Muller 121).

Since this created order is contingent, “God has created contingent agents that act or cause effects contingently” (123).  As a result, we have the potency to do otherwise.  We should also point out the language of “determined” in the medievals.  They weren’t thinking about the determinism vs. libertarianism debate.  Determined simply meant the “terminus whether a quo or ad quem of a causal sequence has been identified” (130).

Therefore, per a future contingent, it is “undetermined” not in the sense that God is not aware of it, but that it doesn’t have a determinate cause.  God knows future contingents as “hypothetically necessary, as the effects of contingent causes” (131).

Paul Helm: Eternal God

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Helm, Paul.  Eternal God: A Study of God Without Time.  New York: Oxford University Press, Second Edition 2010.

Paul Helm is painstakingly thorough in examining the challenges to God’s being outside of time.  Almost too thorough. In any case, this book will likely be remembered as one of the classics in analytic theology.

Flow of the book: If God is outside of time, then a number of challenges and (perceived) difficulties arise.  The traditional view is the Boethian view: all of past, present, and future is present to God. This view is correct in maintaining that God is outside of time. It is open, however, to a number of devastating defeaters.  Helm’s goal is to reformulate the Boethian view in light of these defeaters.

The most challenging section of the book deals with indexicals: I am here at this place at this hour. The problem is that many of these indexicals can’t apply to God’s being timeless.  God can affirm the following proposition?

(1) I know that it is raining today.

The critic says he can’t because this would place God in a time-bound relation.  It’s not clear, though, why God can’t timelessly affirm this proposition. The only force indexicals would have is that God can’t affirm the following proposition:

(2) I know what it is to be married.

This deals more with omniscience than eternality.  In any case, it doesn’t seem like anything is lost.

Can God know future events?  Presumably, he can. This has been a given in almost every form of theistic belief.  Some philosophers like Swinburne say God can’t know the future if he has also given libertarian freedom to his creatures.  The future actions haven’t yet happened; therefore, God can’t know them. Helm offers something along the lines of a rebuttal:

(3) There is no logical connection between the view that the future does not already exist and the view that the future is indeterminate (121).

I think there is an easier rebuttal, though.  Christianity and Judaism (and I presume Islam) believe that some humans can prophesy (with varying degrees of accuracy) about the future.  If they can know the future actions of free creatures, then it stands to reason that God could, too.

Possibilities of Fatalism

Not all fatalisms are the same.  One can mean:

(4) Everything that happens was bound to happen.

It can mean something weaker:

(5) Everything that happens does so because of a logical necessity.

Timelessness and Human Responsibility

(6) God timelessly decreed that B occur at t₂ and this cannot be isolated from his timeless decree of A at t

(7) God timelessly decrees a complete causal matrix of events and actions (170).

Whenever we speak of God’s being and actions, we must realize that God’s being is logically prior to what he does.

Kripkean Terms

Rigid designator: a proper name which has x property in every possible world.

Accidental designator: property in some world.

Using these terms Helm suggests that “God” expresses the individual essence of God (208). A general essence isn’t a particular essence. God has a set of properties unique to himself. These are “God-making” properties.  This is important because “Being the creator of the world’ is not a part of his nature whereas ‘being infinitely good is’” (209).

Eternal Generation of the Son:  “There is no state of the Father that is not a begetting of the Son, and no state of the Son which is not a being begotten by the Father and necessarily there is no time when the Father had not begotten the Son” (285).

Corollary: If God is in time, then it does make sense to speak of a time when the Son was not.  When did the Father beget the Son? Even asking that question illustrates the problem. You can’t say in eternity past, for that is the thing the temporalist denies.

Notes on Muller’s PRRD vol 4

Roscellin: confirmed anti-realist.  This view led him to declare that every existent thing is a unique individual: so-called universals are “mere words.” (Muller 26).  

The problem with Boethuis’s definition of person:   The definition ultimately poses all manner of problems for the doctrines of Trinity and Christ when the concept of individual substance is taken to indicate a unique entity essentially distinct from other similar entities” (27).  

Anselm on Human nature:  Human nature refers to the conjunction of the several properties and predicates that identify the nature, generally considered, as human—and this is prior to the more particular consideration of the single person as human, as participating in human nature. (27)

Anselm on Filioque:  followed standard Augustinian line that the processions::psychological love

  • As for the Greek claim that the concept of double procession resulted in the error of two ultimate principles in the Godhead, Anselm could respond that just as the creation of the world by all three persons does not result in a theory of three ultimate principles, so does the procession of the Spirit from the Father and the Son not result in a theory of two principles: for the three persons create as one God, and the Father and the Son are one God in the procession of the Spirit (Muller)

Difficulty of Defining “Person.”

Alexander of Hales:  good is self-diffusive.   bonum est diffusivum sui.  “Thus, the “distinction” of the persons in the one divine essence is the “difference of relation or of mode of existing” that arises “by reason of origin.’  (Muller 39). Further, “Thus, according to Alexander, distinction in God between essence and person is not a real distinction (secundum rem), but only a distinction of the rational intellect (secundum intelligentiam rationis); nonetheless, the distinction between persons is real even in God

Alexander objects to the claim that the distinction between persons and essence or between relations and the divine substance must either be according to substance or such as subsists between a thing and another thing (secundum rem) or merely according to our intellect (secundum intellectum solum). The first distinction would rule out divine simplicity, the latter would render the Trinity a doctrine fashioned in the human mind. Alexander responds that, in its inward economy, the one and same divine essence, is disposed as Father, who is neither generated nor proceeded from another; as Son, who is generated from another; and as Spirit, who proceeds from both—and that this manner or mode of being is “not merely according to the acceptation of out understanding, but in fact according to the thing itself.” Thus the Godhead must be considered both in terms of “the identity of substance” and in terms of “a disposition according to the consideration of origin or first principle”—in the first instance, there is the essential identify of the divine persons, in the second, there is the disposition or plurality of the Godhead according to “the predicament of relation” (40)

Thomas Aquinas

Latin authors preferred to speak of the Father as principium rather than cause, unlike the Greeks.  An efficient cause, for example, is perceived of as a different substance than its effects (Muller 47)!

Aquinas’s denial of real distinction is a denial of a substantial distinction.   He wants to deny that any distinction that would make the essence one “thing” and the “persons” other “things.”

Attributes do not result in a conceptual opposition.  Relations do.

Early Reformation Doctrine of Trinity

Structure of the Book

Clarifying medieval discussions on filioque:  all Westerns agreed that the Spirit proceeded from Father and Son as from one principia.  Causal language was eventually abandoned, for it implied the Son/Spirit to be of a different substance (effects are not the same substance as causes).  Further, and right before the Reformation, the Trinitarian life ad intra was lining up with the work ad extra (Muller 59).

The Reformation forced thinkers to restate the doctrine of the Trinity anew.  Advances in historical criticism and typology meant that some exegesis needed revisiting.  Muller notes three basic issues: the inheritance of Patristic vocabulary, renewed exegetical battles against the Socinians, and a new philosophical vocabulary (62).  

Subordination:  talk of Christ’s subordination referred to his mediatorial kingdom, when he handed it over to the Father (115).

The Terms of Trinitarian Orthodoxy

Trinitas: equivalent to Trium Unitas: “the subject itself, in its primary definition, denies composition in the Godhead” (169). God is not unitary, but unum; not triplex, but trinum.

Substantia, essentia, ousia: with regard to substance, the individual is primary and the genus secondary in the ontic sense. A genus will always be the predicate of a primary.  We would say “Simon is a man” and not “man is a simon.”

Keckerman:  essence is the whatness or quiddity, substance the existing individual.


Tertullian: a persona is identified by one who has substantia (178).

Socinians: person is identified with primary essence, which would yield three gods.  This allowed them to exclude Son and HS from Godhood.

Turretin: person is an individual intellectual suppositum (III.xxiii.7).  See 2 Cor. 1:11.

Proprietates, relationes, and notiones:

Property:  a distinguishing characteristic of a subsistence not shared with other subsistences (187).

Notio: the way in which the three subsistences are distinct from one another.






The Trinity of Persons in their Unity and Distinction: Theology and Exegesis in the Older Reformed Tradition

Calvin: (see mainly Institutes 1.13.1).

Bullinger: Decades 4.3

Musculus: essence signifies that which is common; substance that which is proper to all persons.  Musculus follows Hilary and Jerome where substance is hypostasis, rather than ousia (Muller 206).

Order and Distinction of the Persons

Keckermann: the mode of God’s existence does not differ from the mode of God’s essence. The persons are distinct not by degree, state, or dignity, but by the order, number, and manner of doing (Trelcatius).

Objection: does essential identity demand personal identiy? The Reformed generally respond that this is true for finite essences (Muller 211).  The orthodox are slowly moving away from the old Cappadocian argument of three men having the essence of manness. The problem is that this moves from “genus (man” to “Genus (God)”, yet God isn’t a genus.

Nor is it a quaternity: the three persons plus the one essence.  Persons and essence are not distinct as a thing (res).

Exegetical Issues and Trajectories

The Reformers assumed a hermeneutic of movement from shadow and promise to fulfillment (214).

The Deity and Person of the Father

Covenant of redemption:

Eternal decree and election of Christ.  God works either by his decree or the execution of it (Perkins). As the Reformed saw that this was Trinitarian, they began to see the covenant of redemption.

The order of the persons ad intra in the opera personalia is mirrored ad extra in the opera appropriata (Muller 268).  These are modes of operation contributing to the ultimately undivided work of the Godhead ad extra. The works of the Son and Spirit terminate on their persons.  By terminate we mean the terminus is paired with a fundamentum. This pair means a relation of acts bringing about relations (268). The fundamentum is the source; the terminus is the conclusion of the action constituting the relation.

Venema: “The Father being the originating–the Son the efficient–and the Holy Spirit the Perfecting cause.”

The Person and Deity of the Son

The problem of subordination:   Col. 1:15 uses protokotos, not protoktistos.  Lordship, not creation (Rijssen).

Generation: a communication of personal existence without any multiplication or division of essence (284).

Aseity of the Son

The issue: Calvin denies explicitly that the Son is from the Father “with respect to his eternal essence” (Muller 325). The Son is generated per Sonship, not divinity.

However, Ursinus: the essence is absolute and communicable.  The person is relative and incommunicable.

Arminius rejected Calvin’s view, insisting that “Christ, as God, has both his sonship and his essence by generation” (329).

Procession of the Holy Spirit

The Reformed try to get around the asymmetry of the Father and Son generating a divine person while the Spirit does not, in the following way:  “in modo, since the way of generation terminates not only in the personalitas of the Son but also in a ‘similitude’, according to which the Son is called the image of the Father, and according to which the Son receives the property of communicating that essence to another person. In contrast, the Spirit does not receive the property of communicating that essence to another person, inasmuch as the way of spiration terminates only in the personalitas of the Spirit and not in a similitude of the Father

Frame: Medieval Philosophy

Frame draws heavily from Leithart’s essay on medieval philosophy.  It is a standard treatment in many ways, starting with Boethius and ending with the nominalists.


Since we are temporal, this means we lose some of our being as time passes.  Not so with God (124).  Boethius takes the chain of being ontology and applies it to time.

His definition of person is problematic:  A person is an individual substance of a rational nature.  As Frame says, “If each person is a substance, then the whole Trinity is one substance and three substances” (125).


Standard summary of his arguments.  Tries to make him a presuppositionalist.  The best we can say is that Anselm presupposes the dogma of the church.   Within that he can use reason and not Scripture.

Towards Scholasticism: Avicenna, Maimonides, Averoes

Heavy influence of neo-Platonism.  Creation is seen as an eternal act of God, not an event in the beginning of time (141).


Standard treatment.  Quite fair to him.  Frame has a fascinating footnote on p.150.  Many traditional theologians say we can know the “who” of God, but not his essence.  Greek theologians denied we could know the essence because in Greek philosophy knowing was a form of dominatingAbsolute knowledge erases differance. One who has the concept of “a thing” has the thing.  Concept is domination.  Knowledge is knowledge only insofar as it “seizes” the thing and has complete certainty.  

It is not surprising, then, that Christian theologians say we can’t know God’s essence.  We certainly cannot bring God under our domination as a thing.  But this raises a problem:  why is Christian discourse obligated to define knowledge this way?

Let’s completely disregard the above def. of knowledge.  Why not rather say with the better moments of the tradition that knowing presupposes–at least in some cases–a loving bond between subject and object?