The Brain Resides in the Soul (Not the Other Way Around)

A great deal of philosophical heat, though rather less light, has been generated in recent decades by the ambition to reduce mind to some more basic reality describable by physics. The physicalist is emboldened by the evident entanglement of brain states with mental states, which seems to require that a Cartesian mind, in kind and subsistence distinct from bodily “extension,” must be at most a mere constitutional monarch, reigning perhaps, but not governing. The physicalists also have had to deal with dissenters within the ranks, however, notably “the new mysterians,”[1] who abjure appeals to spooky entities such as “spirit” or “intellect,” but nonetheless argue against the reducibility of mind and mental life to the mobile quantities described by the natural sciences.

Those three camps—dualism, physicalism, and “mysterianism”—seemed to me to exhaust the contemporary field, until I read the chapter on “consciousness” in David B. Hart’s 2012 The Experience of God, and later the essay “The Spiritual Was More Substantial Than the Material for the Ancients.” Hart proposed to turn this debate on its head: rather than seeing mind as emerging from the body, why not see “spirit as being more substantial, more actual, more ‘supereminently’ real than matter, and in fact as being the pervasive reality in which matter too has to participate in order to be anything at all”?[2] The physicalist tricks himself into thinking that bodies are something solid and undeniable, and the mind something insubstantial and doubtful, but only by failing to observe the latter’s quiet, illuminating presence in and through every act of knowing the sensible world.

Around the same time, I was delving into early modern philosophy, and came to Bishop Berkeley (1685-1753), the Anglo-Irish philosopher and eventual Anglican bishop of Cloyne. Berkeley exists today in the philosophical pantheon principally as the butt of jokes about his alleged “subjective idealism” (an expression he never used). I discovered, however, that he had defended a position analogous to Hart’s in his own fight with reductionists (Hobbes), “mysterians” (Spinoza), and dualists (Descartes).

This is particularly clear in his last work, Siris (1744), his little read and less understood paean to the medicinal virtues of “tar water.” Despite its beginnings in folk medicine and alchemical speculation, this “rude essay,” Berkeley notes near the end, “doth, by insensible transitions, draw the reader into remote inquiries and speculations,” in the form of metaphysical and theological speculation of the most recondite, Neoplatonic kind.[3]

In these later sections of Siris, Berkeley, citing Proclus, proposes that:

There are two sorts of philosophers. The one placed body first in the order of beings, and made the faculty of thinking depend thereupon, supposing that the principles of all things are corporeal: that body most really or principally exists, and all other things in a secondary sense, and by virtue of that. Others, making all corporeal things to be dependent upon soul or mind, think this to exist in the first place and primary sense, and the being of bodies to be altogether derived from, and presuppose that of mind.[4]

This distinction almost certainly looks back to the Eleatic Stranger’s description, in Plato’s Sophist, of the “battle like that of the gods and the giants,” between “the Sons of the Earth” and the “friends of the Forms.”[5] The former “define substance and body as identical (ταὐτὸν σῶμα καὶ οὐσίαν ὁριζόμενοι) and if anyone says that anything else, which has no body, exists, they despise him utterly, and will not listen to any other theory than their own.”[6]

In the early modern period, after a long dormancy during the late-ancient and medieval reigns of first Plato and then Aristotle, the Sons of Earth awoke and went to war, not least in the figures of Thomas Hobbes and Benedict Spinoza, who each developed a metaphysics centered on a bodily and impersonal God who is immanent to, and in some sense identical with, the cosmos. The challenge posed by Hobbes and Spinoza, among others, reinvigorated the “Friends of the Forms,” not least Berkeley, whose entire philosophy might be thought of as a defense of the doctrine of creation, first in the novel idioms of the Enlightenment, and later in the language of a long tradition of Christian Platonism.

This later Berkeley, despite his great interest for contemporary debates in the philosophy of mind and the doctrine of creation alike, has been largely ignored even by Berkeley specialists, and remains almost entirely absent from contemporary Christian theology. A typical Anglophone philosopher encounters Berkeley only in his earliest works, notably The Principles of Human Knowledge (1710, hereafter PHK) and the Three Dialogues (1713, hereafter 3D), written in his early- to mid-twenties. Together, these present what Geneviève Brykman calls Berkeley’s “militant immaterialism.”[7] These works are generally read through the unsympathetic eyes of Berkeley’s earliest inheritors and critics, as in Thomas Reid’s suggestion that Berkeley’s system necessarily collapses into solipsism;[8] Kant’s distinction between his own “critical idealism” and Berkeley’s “dogmatic idealism,” which “declares the things in space to be mere imaginings”;[9] or Hegel’s insistence that Berkeley’s philosophy represents an “idealism, in which all external reality disappears.”[10]

Even the small world of sympathetic Berkeley scholarship is for the most part focused myopically on the Bishop’s early works (e.g., The Principles of Human Knowledge and the Three Dialogues of Hylas and Philonous) and particularly on the ways in which they anticipate more recent philosophical developments, whether logical positivism, use-theories of meaning, or anti-realism. And this scholarly culture has strongly marked the small but growing theological literature on Berkeley, which is likewise narrowly focused on the Principles and the Dialogues. There is, however, a scattering of dissenting scholars who swim against the current by seeing in Berkeley’s later works, particularly Alciphron (1734) and Siris (1744), significant and salubrious departures from the earlier ones, both in substance and in style. In these works, Berkeley turns in a humbler spirit to the great philosophers of antiquity, and finds resources in them for marrying his commitment to the priority of the intelligible over the sensible with common-sense notions about the world’s independence of my mind or yours.

Before we consider Siris, however, we first need to understand the metaphysical and ultimately theological concerns which gave rise to Berkeley’s earliest works, and the apparently insoluble problems they generated, questions whose answers Berkeley hit on only in the later sections of his last work. The Berkeley of the Principles was struck by the immediacy of our encounter with the reality of sensibles, which only a philosophic dust-cloud could obscure.[11] The thickest such cloud, for the young Berkeley, was “MATTER,” understood in Locke’s sense, as “an inert, senseless substance, in which extension, figure, motion DO ACTUALLY SUBSIST,”[12] and which is constructed as a great mechanism, in which even the mind—viz., the brain—is enmeshed.[13]

That his paradigm for such substances is Locke’s bodily “real essence,” a constellation of massy, moving, and mind-independent particles, becomes clearer in the next section, where Berkeley rejects Locke’s view that such mind-independent substances might really possess such “primary qualities” as extension and motion, while their interactions with the human senses would give rise to such “secondary qualities” as color, taste, smell, or sound.[14] As he later puts the point in Principles of Human Knowledge, “One great inducement to our pronouncing ourselves ignorant of the nature of things is the current opinion that everything includes within itself the cause of its properties; or that there is in each object an inward essence which is the source whence its discernble qualities flow, and whereon they depend . . . Of late, [appearances] are mostly resolved into mechanical causes, to wit, the figure, motion, weight, and suchlike qualities, of insensible particles.”[15]

And in the second of the Three Dialogues, Hylas describes “the modern way of . . . accounting for our sensations or ideas,” which epitomizes Berkeley’s worry that the mechanical philosophy reduces cognition to a matter of engineering:

It is supposed the soul makes her residence in some part of the brain, from which the nerves take their rise, and are thence extended to all parts of the body; and that outward objects, by the different impressions they make on the organs of sense, communicate certain vibrative motions to the nerves; and these being filled with spirits propagate them to the brain or seat of the soul, which, according to the various impressions or traces thereby made in the brain, is variously affected with ideas.[16] 

The picture here is of a self-subsisting mechanism which exists without (both outside of and indifferent to) the mind, and to which the mind gains periodic and indirect access by way of the senses.

If Locke was the usual foil against whom Berkeley tested his own philosophy, it is also true that Berkeley saw him as merely the most presentable figure in a mob of impiety and confusion. “Locke holds some dangerous opinions,” he wrote in his Philosophical Commentaries (the notebooks in which he tried out the ideas that made their way into PHK), “such as the infinity and eternity of Space and the possibility of Matter's thinking.”[17] Why is the doctrine of space’s infinity so dangerous? Berkeley’s answer comes a few pages later: “Hobbs & Spinosa make God extended. Locke also seems to do the same.”[18] What Matthew Stewart says of Leibniz applies equally to Berkeley: “When he looked at Descartes and Locke, he saw Spinoza.”[19]

Spinoza made this identification of God with extension itself, Berkeley seems to think, because he regarded extension as something essentially mind-independent: “I say that extension is not conceived in and through itself, contrary to what Spinoza said.”[20] And this proposed identity, Berkeley insists, explains why “Spinosa (vid. Præf. Opera Posthum.) will have God to be ‘omnium rerum causa immanens [the immanent cause of all things],’ and to countenance this produces that of St. Paul, ‘in Him we live,’ &c. Now this of St. Paul may be explained by my doctrine as well as Spinosa's, or Locke's, or Hobbs's, or Raphson's, &c.”[21] On his view, by contrast, the “world without thought is nec quid, nec quantum, nec quale [neither a thing, nor a quantity, nor a quality],” no clearer than Aristotle’s obscure definition of “prime matter,” with which the new, post-scholastic philosophies were thought to have a decisive break.[22]

Berkeley’s most straightforward argument against the possibility of a mind-independent cause of our perceptual beliefs is sometimes (following Kenneth Winkler) called his “Master Argument”: “You allow the things immediately perceived by sense to exist nowhere without the mind; but there is nothing perceived by sense which is not perceived immediately: therefore there is nothing sensible that exists without the mind.”[23] Put schematically:

1. We perceive ordinary objects (houses, mountains, etc.).
2. We perceive only ideas. (Note that Hylas grants this premise.) Therefore,
3. Ordinary objects are ideas.[24]

For Berkeley, any putative material substrate, understood as the qualitative inversion of the ordinary, sensible world, would be incapable of grounding perceptible qualities: “But how can that which is sensible be like that which is insensible? Can a real thing, in itself invisible, be like a colour; or a real thing, which is not audible, be like a sound? In a word, can anything be like a sensation or idea, but another sensation or idea?”[25] Better by far, he insists, to cut the cord between sensible objects and their putative material archetypes: “Is it not a sufficient evidence to me of the existence of this glove, that I see it, and feel it, and wear it? Or, if this will not do, how is it possible I should be assured of the reality of this thing, which I actually see in this place, by supposing that some unknown thing, which I never did or can see, exists after an unknown manner, in an unknown place, or in no place at all?”[26] It is Locke and not he who denies that a cherry is red, squishy, and sweet.[27]

The principal difficulty facing Berkeley’s “militant immaterialism,” however, is its lack of clarity about the status of unperceived sensibles, now often identified, after Ronald Knox’s immortal limericks, with the fate of the “tree in the quad”:

There was a young man who said God
Must think it exceedingly odd.
If he finds that this tree,
Continues to be
When there’s no one about in the Quad.

REPLY:

Dear Sir: Your astonishment’s odd
I am always about in the Quad
And that’s why the tree
Will continue to be
Since observed by, Yours faithfully, God. 

As in Knox’s “REPLY,” Berkeley’s usual way of framing some sensible reality’s independence of your mind or mine is in terms of its “archetype’s” subsistence in the mind of God. So, in the Principles of Human Knowledge, Berkeley writes: “whoever shall reflect, and take care to understand what he says, will . . . acknowledge that all sensible qualities are alike sensations and alike real; that where the extension is, there is the colour, too, to wit, in his mind, and that their archetypes can exist only in some other mind.”[28]

He makes a similar point in the Three Dialogues:

To me it is evident for the reasons you allow of, that sensible things cannot exist otherwise than in a mind or spirit. Whence I conclude, not that they have no real existence, but that, seeing they depend not on my thought, and have all existence distinct from being perceived by me, there must be some other Mind wherein they exist. As sure, therefore, as the sensible world really exists, so sure is there an infinite omnipresent Spirit who contains and supports it.[29]

In the third Dialogue, Philonous insists to Hylas that on his account perceptual beliefs are still just as accountable to an external, truth-making “archetype” as they are on the materialist view: “So may you suppose an external archetype on my principles; external, I mean, to your own mind; though indeed it must be supposed to exist in that mind which comprehends all things; but then this serves all the ends of identity, as well as if it existed out of a mind.”[30]

In a letter to Berkeley in September 1729, Samuel Johnson (not the English conversationalist, but the former Yale tutor and founding President of King’s College, aka Columbia University), summarized Berkeley’s account of divine ideas by stressing that the objectivity of the sensible order is guaranteed, for Berkeley, by its correspondence to the order of divine ideas:

I understand you, that there is a two-fold existence of things or ideas, one in the divine mind, and the other in created minds; the one archetypal, and the other ectypal; that, therefore, the real original and permanent existence of things is archetypal, being ideas in mente Divinâ, and that our ideas are copies of them, and so far forth real things as they are correspondent to their archetypes and exhibited to us, or begotten in us by the will of the Almighty, in such measure and degrees and by such stated laws and rules as He is pleased to observe.[31]

He concludes from this “that, therefore, there is no unperceived substance intervening between the divine ideas and ours as a medium, occasion or instrument by which He begets our ideas in us, but that which was thought to be the material existence of things is in truth only ideal in the divine mind. Do I understand you right?”[32]

Berkeley’s initial reply (November 1729) included no response to Johnson’s question about divine ideas, but when pressed about the matter in a second letter (March 1730), he confirmed Johnson’s intuition that he was in favor of collapsing the distinction between the truth condition of our knowledge that p, and the mode by which God knows that p: “I have no objection against calling the ideas in the mind of God archetypes of yours. But I object against those archetypes by philosophers supposed to be real things, and to have an absolute rational existence distinct from their being perceived by any mind whatsoever.”[33]

Berkeley’s two-place theory of sensibles, as divided between the immediate perception of them by a finite perceiver, and the abstract idea of them which grounds them in the divine intellect, with no intermediate state in rerum natura, was clearly a response, at some level, to his worry about the skeptical implications of allowing a mind-independent “material world.” Berkeley’s increasing reliance on the divine ideas is one index, however, of the extent to which he moved on from the youthful worries about skepticism that motivated his early immaterialism, in the interests of developing a more robust metaphysical conception of reality. As Christian Wenz observes, Berkeley’s “fear of the charge of skepticism forced him to conceal his Christian neo-Platonism until his interest in the whole problem of skepticism had waned. And then he wrote the Siris.”[34]

Indeed, when we turn from the “militant immaterialism” of the Principles to the “ontological immaterialism” of Siris (1744),[35] which John Milbank has rightly called “the ‘romance’ of Berkeley’s metaphysics of light,”[36] we find a scene which is subtly but importantly different from the Principles (1710): here, rather than a solid reality which only philosophic dust clouds can obscure, the sensible world is best understood as a shadow cast by spiritual realities. Martial Gueroult captured the difference nicely: in Siris,

The sensible is nothing but the appearance; we believe it to be real because of the strong impression it exercises on us, while the only true reality is the intellectual Idea, the source of stability and unity . . . Certainly, [in Siris] the New Principle remains in certain respects. It is always the case that nothing can be which isn’t in and by a mind. But everything is transformed, since the reality of the external thing no longer resides in the passivity of its perception, but in the spiritual activity which establishes the unity of the thing. In place of "to be is to be perceived" is substituted the principle of Parmenides: "To understand and to be are the same."[37]

The young Berkeley had brashly written, of his new “Principle” (esse est percipi), “This I think wholly new. I am sure 'tis new to me.”[38] In his first published works, he adopted a deliberately “short-sighted” perspective,[39] myopically and relentlessly focused on the meaninglessness of talk about unperceived and unperceiving material substances; “we have first raised a dust, and then complained we cannot see.”[40]

In time, however, he came to see that this kind of myopic criticism was dangerous too—in an essay for the Guardian in 1718, Berkeley compares free-thinkers to flies complaining about the imperfections in one stone in St. Paul’s Cathedral,[41] and in Alciphron (1734), the dialogue’s free-thinking antagonists are given Cicero’s derisive label, “minute philosophers,” because (in Alciphron’s optimistic assessment) of their “considering things minutely, and not swallowing them in the gross,”[42] but perhaps also, as Euphranor complains, because they “reduce all the knowledge, ideas, and theories that men have to sense; shrink and downgrade human nature to the narrow low standard of animal life; and assign to us only a small pittance of time instead of immortality.”[43]

Alciphron marks a particularly important turning point for Berkeley’s philosophic style. While the author’s position is usually identified with that of the pious Euphranor and Crito, Brykman points out that the character most like the young Berkeley, at least in terms of intellectual style, is surely the free-thinker Alciphron himself—after all, it is he who emphasizes that we must think with the wise but speak with the vulgar.[44] Brykman reads the work as a subtle critique of the strategies employed in his early works, notably his derision for authority and tradition, and his theoretical revisions of ordinary language.[45] By the conclusion of Siris, this diffidence about his earlier brash style has turned to outright condemnation, as he writes,

The eye by long use comes to see even in the darkest cavern: and there is no subject so obscure, but we may discern some glimpse of truth by long poring on it . . . He that would make a real progress in knowledge, must dedicate his age as well as youth, the later growth as well as the first fruits, at the altar of truth.[46]

Unsurprisingly, throughout this last work, Berkeley freely attributes his most cherished ideas to the Platonists. “The Pythagoreans and Platonists,” he writes,

Had a notion of the true system of the world: they distinguished the primary qualities in bodies from the secondary, making the former be physical causes, and they understood physical causes in a right sense: They saw that a mind infinite in power, unextended, invisible, immortal, governed, connected and contained all things: they saw there was no such thing as real absolute space: that mind, soul, or spirit, truly and really exists: that bodies exist only in a secondary and dependent sense: that the soul therefore is the place of forms.[47]

Berkeley goes so far as to interpret both Plato and Aristotle as early precursors of his own thought, arguing that neither of them admitted “an absolute actual existence of sensible or corporeal things.”[48]

In particular, Berkeley repeatedly braids his immaterialism together with Plato’s Allegory of the Cave, which forms a leitmotiv running through the second half of Siris: “It cannot be denied, that with respect to this universe of things, we in this mortal state are like men educated in Plato’s cave, looking on shadows with our backs turned to the light.”[49] This is because “sense and experience acquaint us, with the course and analogy of appearances or natural effects”—these are the appearances, the shadows on the cave wall. By contrast,

Thought, reason, intellect, introduce us into the knowledge of their causes. Sensible appearances, though of a flowing, unstable, and uncertain nature, [cf. PHK 89, where sensibles are “fleeting, inert, dependent”] yet having first occupied the mind, they do by an early prevention, render the after task of thought more difficult . . . Although it be certain, that the principles of science are neither objects of sense nor imagination; and that intellect and reason are alone the sure guides to truth.[50]

What are these true principles of science? They are what the “physicist” discovers if he “ascends from the sensible into the intellectual world, and beholds things in a new light and a new order[;] he will then change his system and perceive, that what he took for substances and causes are but fleeting shadows; that the mind contains all, and acts all, and is to all created beings the source of unity and identity, harmony and order, existence and stability.”[51] Likewise, “When we enter the province of the philosophia prima, we discover another order of beings, mind and its acts, permanent being, not dependent on corporeal things, nor resulting, not connected, nor contained; but containing, connecting, enlivening the whole frame; and imparting those motions, forms, qualities, and that order and symmetry to all those transient phenomena.”[52]

What mind does he have in mind? Earlier in Siris, he makes clear that the paradigmatic knower in view here is God: “There is a mind that governs and actuates this mundane system, as the proper real agent and cause. And that the inferior instrumental cause is pure aether, fire, or the substance of light which is applied and determined by an infinite mind in the macrocosm or universe, with unlimited power, and according to stated rules.”[53] Berkeley later cites Parmenides’s cryptic maxim, “To understand and to be are . . . the same thing,”[54] which is perhaps why he can also write, “God alone exists. This was the doctrine of Heraclitus, Plato, and other ancients.”[55] Unrestricted being, for Berkeley as much as for Aquinas or Bonaventure, is pure intellect, so that if existence is to be predicated of God, it can be spoken of creatures only improperly, by way of an “analogy of attribution.”[56] To be anything at all—even to be a quark flickering into existence for a few microns in the depths of space—is to participate in this subsistent act of intelligibility the LORD is. At the work’s very end, Berkeley finally rises from divine unity to a strikingly “Dionysian” Trinitarian specification of this framework:

In the administration of all things there is authority to establish, law to direct, and justice to execute. There is first the source of all perfection, or fons deitatis, secondly the supreme Reason, order or logos, and lastly the Spirit which quickens and inspires. We are sprung from the father, irradiated or enlightened by the son, and moved by the spirit.[57]

Even as he maintains sensible beings’ dependence on the divine intellect, the Berkeley of Siris adopts a far more relaxed attitude about their relation to finite perceivers than he had in earlier works. Indeed, it might be better to say that he had come to see that his former sharp dualism between the two domains of “spirits” and their “ideas” in fact define two poles of a spectrum, or rather of the “chain” that “runs . . . throughout the whole system of beings,”[58] from the pure potentiality of “matter” to the “actus purus” that God is. Especially significant in this light is the following:

Body is opposite to spirit or mind. We have a notion of spirit from thought and action. We have a notion of body from resistance. So far as there is real power, there is spirit. So far forth as there is resistance, there is inability or want of power. That is, there is a negation of spirit. We are embodied, that is, we are clogged by weight, and hindered by resistance. But in respect of a perfect spirit, there is nothing hard or impenetrable: there is no resistance to the Deity: Nor hath he any body: nor is the supreme being united to the world, as the soul of an animal is to its body, which necessarily implieth defect, both as an instrument, and as a constant weight and impediment.[59]

Body is opposed to spirit, on this view, in being its “negation”—unlike in Principles, we no longer have two kinds of being, one depending on the other, but rather a single kind of being. Spirit is arrayed in a graded hierarchy according to its restriction or limitation by “body.”

Insofar as something is active, then, it is spirit. But only God is “actus purus”; only God is truly infinite, free from all limitations and identical with all perfections. Insofar as we are finite, we are imperfectly actual, and so subject to resistance—resistance to where we can go and to what we can know, in the first instance. To encounter resistance is to encounter the world from a distinct vantage, from a finite place in space-time. But equally, to encounter resistance is to be available and even vulnerable to the world from this distinct vantage. Finitude, availability, passivity: this, at least for the Berkeley of Siris, is just what it means to be a body. This is another helpful illustration of why it is nonsense, for Berkeley, to say that bodies might exist independently of spirits or minds—“body” is a privative category, a way of marking the limitation of spirit. Spirit is how we name a creature’s activity; body is how we name its finitude. Talk of a mind-independent body makes exactly as much sense, on this view, as talk of the Cheshire cat’s smile continuing to hang in the air after its body has vanished.

No longer shackled by the bright-line division between perceivers and perceived, Berkeley’s late neo-Platonism accommodated a realist outlook about unperceived sensibles much more easily than his earlier thought. As Gabriel Moked has argued trenchantly, the Berkeley of the Siris has even come to endorse a “corpuscularian” philosophy of his own, which is happily realist about the existence of microscopic particles.[60] So, Berkeley writes of “the extreme minuteness, mobility, and momentum of [mercury’s] parts,”[61] and even supposes, with Newton, that light has a corpuscular structure.[62]

These particles are not, of course, imperceptible in the sense of being unknowable, nor do even they exist unperceived. However, their existence as sensibles is no longer carefully hedged about with the counter-factual disclaimers and speculations about temporal discontinuity that the young Berkeley’s inner Bertrand Russell was constantly whispering in his ear. Rather, the physical world—even its microscopic constituents—subsists in being known and willed by the LORD, and it lies within the domain of the intelligible which is the “space of reasons.”[63] As Moked puts it, “In the view of the author of Siris, both the primary and secondary qualities are real (because equally perceived by an infinite Observer, and equally perceivable by all finite observers) and mind-dependent.”[64]

The late Berkeley’s most striking deviation from his early immaterialism is his rehabilitation of the concept of “matter” itself. Having read more widely and sympathetically, he seems to have outgrown his youthful conflation of the Lockean corpuscular real essence with Platonist-Aristotelian “prima materia.” Now, he recognizes, “Neither Plato nor Aristotle by matter, hylē, understood corporeal substance, whatever the moderns understand by that word. To them certainly it signified no positive actual being,”[65] but rather “only a pura potentia, a mere possibility.”[66] “That matter is actually nothing, but potentially all things,” he notes, “is the doctrine of Aristotle, Theophrastus, and all the ancient Peripatetics.”[67]

Where Principles-Berkeley is drawn to a bright-line Cartesian distinction between spirits and sensibles, Siris-Berkeley has shifted to something like a Leibnizian perspective, in which spirit-as-actuality is arrayed in varying degrees of intensity across the great chain of being, rising from the pure potency of matter to the pure actuality of the LORD.[68] This would surely have delighted Leibniz, who, upon reading Berkeley’s Principles late in life, scrawled, “The true substances are Monads, or Perceivers. But the author ought to have gone on further, namely to infinite Monads, constituting all things, and to their pre-established harmony.”[69]

For Berkeley, the single filament threaded through each link in the Great Chain of Being is light: “The Platonic philosophers,” Berkeley observes, citing Plotinus and “Marsilius Ficinus” in particular, “do wonderfully refine upon light, and soar very high: from coal to flame; from flame to light; from this visible light to the occult light of the celestial or mundane soul, which they supposed to pervade and agitate the substance of the universe by its vigorous and expansive motion.”[70] Berkeley, sounding much more like Robert Grosseteste or Bonaventure than the author of The Principles of Human Knowledge, claims that this occult light “comprehends, in a mixed state, the seeds, the natural causes and forms of all sublunary things.”[71] Also like Bonaventure, Berkeley maintains that the most eminent and universal secondary “cause” is “pure aether, fire, or the substance of light which is applied and determined by an infinite mind in the macrocosm or universe, with unlimited power, and according to stated rules.”[72] Berkeley observes “that there are many passages in holy scripture, that would make one think, the supreme being was in a peculiar manner present and manifest in the element of fire,”[73] and even wonders if the Psalmist might have been in earnest when wrote that God “maketh flaming fire his ministers.”[74]

A physics of light easily shifts, in Berkeley’s hands, into a metaphysics of light, as when he muses,

At the transfiguration, the apostles saw our Saviour’s face shining as the sun, and his raiment white as light, also a lucid cloud or body of light, out of which the voice came; which visible light and splendor was, not many centuries ago, maintained by the Greek church, to have been divine, and uncreated, and the very glory of God: as may be seen in the history wrote by the emperor John Cantacuzene.[75]

Berkeley here stands comfortably within “the Augustinian-Franciscan tradition” of “the metaphysics of light,” which Christian Moevs describes as “descended from the Neo-Platonic tendency, absorbed by the Christian patristic tradition, to identify God with light in a strict sense, and to think of created things as the reflection or radiation of that light.”[76] I submit that this applies at least as well to the metaphysics of Siris as to Plotinus or Bonaventure: as he discourses on light, Berkeley moves us from the thought of shadowy sensibles, drifting in the borderlands of being, to the pure lucidity of the LORD, “in whom there is no shadow of turning” (James 1:17).