Analytic Metaphysics as a Copernican Devolution in Philosophy.

By Robert Hanna

Christian Wolff (1679–1754)



Analytic Metaphysics as a Copernican Devolution in Philosophy

The central theme of [Writing the Book of the World] is: realism about structure. The world has a distinguished structure, a privileged description. For a representation to be fully successful, truth is not enough; the representation must also use the right concepts, so that its conceptual structure matches reality’s structure. There is an objectively correct way to “write the book of the world.” … I connect structure to fundamentality. The joint-carving notions are the fundamental notions; a fact is fundamental when it is stated in joint-carving terms. A central task of metaphysics has always been to discern the ultimate or fundamental reality underlying the appearances. I think of this task as the investigation of reality’s structure. (Sider, 2011: p. vii)

It’s an ironic fact that philosophers who fail to take the history of philosophy sufficiently seriously, are doomed to repeat its errors.

As a striking case-in-point, let’s consider recent and contemporary Analytic metaphysics, which, for all its logico-technical brilliance and its philosophical rigor, essentially amounts to what I’ll call a Copernican Devolution in philosophy (Hanna, 2017a), a retrograde philosophical epicycle within post-classical Analytic philosophy that brings us back, full-circle, to naive, pre-Kantian, pre-critical conceptions of mind, knowledge, the world, and philosophy itself, that are essentially Cartesian, Spinozan, and especially Leibnizian-Wolffian (see, e.g., Hettche and Dyck, 2019), in their specific character and basic implications.

The leading figures of Analytic metaphysics include Saul Kripke, David Lewis, Kit Fine, Theodore Sider, David Chalmers, and Timothy Williamson; and some of its canonical texts are Kripke’s Naming and Necessity (1980), Lewis’s On the Plurality of Worlds (1986), Fine’s essays “Essence and Modality” and “Senses of Essence” (1994, 1995), and his Modality and Tense: Philosophical Papers (2005), Sider’s Writing the Book of the World (2011), Chalmers’s Constructing the World (2012), and Williamson’s Modal Logic as Metaphysics (2013).

Characteristic of this recent and contemporary philosophical backsliding are dogmatic commitments to noumenal realism in ontology, and to conceptualism about the nature of mental representation; to a heavy reliance on modal logic as somehow providing direct insight into the ultimate structure of noumenal reality; and to a dogmatic scientific naturalism, including scientism, that’s (usually) combined with scientific essentialism.

Analytic metaphysics’s Copernican Devolution is, in fact, a disastrously regressive turn in philosophy.

More specifically, recent and contemporary Analytic metaphysicians really and truly need to learn Kant’s late eighteenth-century lessons (i) about the inherent limits of human cognition and knowledge, (ii) about the unsoundness of all possible ontological arguments from logical or analytic necessity to actual or real existence, (iii) about the essential cognitive-semantic difference between (iiia) mere logical, analytic (aka, “weak metaphysical”) possibility and (iiib) real, synthetic (aka, “strong metaphysical”) possibility, and (iv) about the essential ontological difference between noumena and phenomena.

For without these insights, they have been, are, and forever will be inevitably led into the very same “obscurity and contradictions” that beset classical metaphysics prior to Kant (CPR Avii).

But as they say, it’s an ill wind that blows nobody any good: that is, few misfortunes are so bad that they don’t have some unintended good side effects for somebody or another.

Hence, seeing Analytic metaphysics’s Copernican Devolution for what it really is, i.e., a philosophically disastrous regression, makes it really possible for us to provide a well-focused re-characterization of Kant’s metaphysics in a contemporary context, looking toward the near future.

Or otherwise put, seeing Analytic metaphysics for what it really is, makes it really possible to provide a broadly and radically Kantian metaphysics that constitutes not only a Second Copernican Revolution in philosophy, but also a philosophy of the future (Hanna, 2021a: ch. XVIII, esp. section XVIII.6).

In this light, Kant’s, or at least a broadly and radically Kantian, critical metaphysics is decisively what I’ll call a “real” (or, alternatively, “human-faced”) metaphysics, and correspondingly it can be illuminatingly presented in terms that specially emphasize what I call Kant’s “proto-critical” period in the late 1760s and early 1770s and also his “post-critical” period in the late 1780s and 1790s, both of which are somewhat neglected or undervalued, even by contemporary Kantians (Hanna, 2016).

Looked at this way, Kant’s, or at least a broadly and radically Kantian, real or human-faced metaphysics consists, fundamentally, of the following six commitments: (i) a strict evidential appeal to human experience, which I call the criterion of phenomenological adequacy for metaphysical theories, (ii) a radical epistemic agnosticism about both the nature and existence of noumenal reality (Hanna, 2017b), (iii) a thoroughgoing diagnostic critique of deep confusions in “ontological argument”-style (and more generally, noumenal-metaphysical) reasoning that’s driven by modal logic, (iv) a maximally strong version of non-conceptualism in the theory of mental representation (Hanna, 2015: ch. 2), and correspondingly, a direct argument for transcendental idealism from the nature of human sensibility together with strong non-conceptualism, that’s essentially in place by the time of Kant’s famous letter to Marcus Herz in 1772 (C 10:129–35) (Hanna, 2016), (v) modal dualism and apriorism (according to which there are two essentially distinct types of necessity, both of which are irreducibly a priori, combined with a strong commitment to the “necessity if and only if apriority” thesis) (Hanna, 2015: ch. 4), and finally, (vi) a theory of synthetic a priori truth and knowledge, grounded directly on strong non-conceptualism (Hanna, 2015: chs. 6–8).

In freely going back and forth between Kant’s philosophy and recent or contemporary philosophy, I’m applying the following strong metaphilosophical principle that I call The No-Deep-Difference Thesis:

There’s no fundamental difference in philosophical content between the history of philosophy and recent or contemporary philosophy. (Hanna, 2009)

Otherwise put, in doing recent or contemporary philosophy one is thereby directly engaging with the history of philosophy, and in doing the history of philosophy one is thereby directly engaging with recent or contemporary philosophy: there is no serious or substantive distinction to be drawn between the two.

In the B preface of the first Critique, Kant says that “there is no doubt that up to now the procedure of metaphysics has been a mere groping, and what is the worst, a groping among mere concepts [bloßen Begriffen]” (CPR Bxv).

A “mere concept” is the same as an empty (leer) concept or noumenal concept, which in turn is a concept that is minimally well-formed in both a formal-syntactical and sortal sense, and also logically self-consistent, but essentially disconnected from human sensibility and actual or possible sensory intuition and all its apparent or manifestly real natural objects, hence a concept that does not have objective validity (objective Gültigkeit).

In a way that’s smoothly compatible with Kant’s, or at least with this broadly and radically Kantian, critical line of thinking, in the mid-2010s, Peter Unger entitled his bang-on-target critique of the Analytic tradition Empty Ideas (Unger 2014).

But according to Kant’s, or at least to a broadly and radically Kantian philosophy, real metaphysics must be evidentially grounded on human experience.

Or otherwise put, real metaphysics designs its basic metaphysical (including ontological) theses and explanations in order to conform strictly to all and only what is phenomenologically self-evident in human experience.

By “phenomenologically self-evident” I mean this:

A claim C is phenomenologically self-evident for a rational human subject S if and only if (i) S’s belief in C relies on directly-given conscious or self-conscious manifest evidence about human experience, and (ii) C’s denial is either logically or conceptually self-contradictory (i.e., it’s an analytic self-contradiction), really metaphysically impossible (i.e., it’s a Kantian synthetic a priori impossibility), or pragmatically self-stultifying for S (i.e., it’s what Kant calls “a contradiction in [S’s] own will” in the Groundwork of the Metaphysics of Morals [GMM 4: 424]).

In turn, this leads directly to what I call the criterion of phenomenological adequacy for metaphysical theories:

A metaphysical theory MT is phenomenologically adequate if and only if MT is evidentially grounded on all and only phenomenologically self-evident theses.

By this criterion, Analytic metaphysics is clearly phenomenologically inadequate, and so is classical Rationalist metaphysics more generally, and especially Leibnizian-Wolffian metaphysics in particular, whereas by sharp contrast, Kant’s, or at least a broadly and radically Kantian, real metaphysics of transcendental idealism is, arguably, fully phenomenologically adequate.

According to Kant, or at least to any broadly and radically Kantian philosopher (Hanna, 2021d), both the origins and limits of human cognition or Erkenntnis are determined by the nature of our specifically human sensibility or Sinnlichkeit (CPR B1, A19–49/B33–73).

In particular, there is an inherent cognitive-semantic constraint on all fully or “thickly” meaningful cognition: a cognition is “objectively valid,” i.e., fully or “thickly” meaningful, if and only if it presupposes actual or possible externally-triggered sensory intuitions or Anschauungen of empirical objects (CPR A238–42/B298–300, A289/B345), presented within the global, framing structures of egocentrically-centered, orientable (i.e., it contains intrinsic enantiomorphic directions determined by a subject embedded in the space or time) phenomenal space and time.

Empirical objects in this specific, anthropocentric sense are appearances (Erscheinungen) or phenomena; by sharp contrast, objects of cognition which, if they existed, would fall outside the scope of human sensibility, are mere “entities of the understanding [Verstandeswesen]” or noumena (CPR A235–60/B294–315, esp. B306).

In short, a noumenon, if it were to exist, would be a non-sensory, non-empirical, non-spatiotemporal, trans-human object, a supersensible object (CPR A254–55/B355).

If, in addition to being a noumenon in this supersensible-object sense (aka “a noumenon in the negative sense”), any noumenal object which, if it were to exist, would also be an individual Cartesian/Spinozan/Leibnizian/Wolffian substance, whose nature is completely determined by intrinsic non-relational properties, would be a “thing in itself [Ding an sich]” (aka, “a noumenon in the positive sense”) (CPR B306–7).

Now, I’m being fairly careful about my formulations here, in two ways.

First, I’m distinguishing between negative noumena (“supersensible” objects in the minimal sense of non-sensory objects) and positive noumena (things in themselves).


Because I think it’s arguable that Kant himself held, or at least that a broadly and radically Kantian philosopher can defensibly hold, that there are perfectly legitimate negative noumena, or supersensible/non-sensory objects (for example, abstract objects in the formal sciences, especially mathematical objects like numbers), that aren’t positive noumena or things in themselves (for example, God, immortal souls, etc.), and indeed are at least partially constituted by (by being in necessary conformity with) the forms of our sensible intuition, and hence they are thoroughly — as it were — phenoumenal.

Second, I’m framing the concepts of a noumenon and of a thing in itself counterfactually, hence I’m not committing Kant, or at least any broadly and radically Kantian philosopher, to the claim that things in themselves really exist.


Because I think that we should not automatically assume that Kant, or at least any broadly and radically Kantian philosopher, believes that noumena or things in themselves really exist.

This of course is one of the great controversies in Kant-interpretation and Kantian philosophy more generally.

And my own view is that Kant is best and most charitably interpreted as a “methodological eliminativist” about things in themselves (CPR A30/B45, A255/B310, A286–87/B343) (Hanna, 2017b).

But at the very least, we need to remain open-minded and not be dogmatic about Kant’s, or at least any broadly and radically Kantian philosopher’s, supposed commitment to the real existence of things in themselves, especially given Kant’s own deep and fully explicit insight about the basic ontological distinction between (i) logically or analytically defined objects (merely thinkable objects), and (ii) actually or really existing objects (experienceable, knowable objects).

Back now to Kant’s, or at least to a broadly and radically Kantian, cognitive semantics.

For Kant himself, or at least for broadly Kantian cognitive semanticists, a cognition is fully meaningful if and only if it is empirically meaningful from the human standpoint.

Failing this, a cognition is “empty [Leer]” (CPR A51/B75), and therefore it not only (i) lacks a directly referential, empirical-intuitional grounding in actually existing empirical objects, but also (ii) lacks a truth-value (hence it is a “truth-value gap”) (CPR A58/B83).

Incidentally, element (i) is a crucial feature of Kant’s famous critique of ontological arguments for God’s existence: all such arguments lack a directly referential, empirical-intuitional grounding in actually existing empirical objects; hence the predicate “exists,” as deployed in such arguments, is merely a “logical” predicate, and not a “real” or “determining” predicate.

Now, it’s important to recognize that, for Kant himself, or at least for broadly and radically Kantian cognitive semanticists, “empty” cognition need not necessarily be wholly meaningless, or nonsense: it can be partially or “thinly” meaningful if (and only if) it is logically well-formed according to the logical forms of judgment/categories, and also conceptually and/or logically consistent (CPR Bxxvi n., A239/B298).

This is what Kant calls mere “thinking [Denken],” according to concepts (Begriffen).

In turn recognizing our natural capacity for mere thinking is metaphilosophically important because mere thinking is characteristic of classical metaphysics, and consequently also of recent or contemporary Analytic metaphysics.

Thinking about X establishes the logical or analytic possibility of X; but it doesn’t establish the real or synthetic possibility of X.

Hence a crucial mistake in classical Rationalist metaphysics, especially in Leibnizian-Wolffian metaphsyivs, and correspondingly a crucial mistake in recent or contemporary Analytic metaphysics, is to confuse logical or analytic possibility/necessity with real or synthetic possibility/necessity.

As Kant aptly and crisply puts it, this metaphysical confusion leads directly to “obscurity and contradictions” (CPR Aviii).

In other words, Kripke, David Lewis, Fine, Sider, Chalmers, and Williamson, for all their logico-technical brilliance and their philosophical rigor, and even despite their high-powered professional academic status, are every bit as philosophically confused, dogmatic, and mistaken as Christian Wolff was.

They make all the same old mistakes, just as if they’d never been made before, 240 years ago.

For example, when Sider asserts in 2011, without any doubt, hesitation, or irony whatsoever, just as if the previous 230 years of European philosophy (i.e., from 1781, the year the Critique of Pure Reason was first published, to 2011) had never happened, that “[t]he world has a distinguished structure, a privileged description,” that “[f]or a representation to be fully successful, truth is not enough; the representation must also use the right concepts, so that its conceptual structure matches reality’s structure,” and that “there is an objectively correct way to ‘write the book of the world’” (Sider, 2011: p. vii), it simply takes your Kantian breath away: really?, and on what epistemic and cognitive-semantic grounds are you asserting this?

On the contrary, according to Kant, or at least to any broadly and radically Kantian philosopher, real metaphysics is based fundamentally on reasoning with real or synthetic possibilities/necessities, not on reasoning with logical or analytic possibilities/ necessities.

In any case, the cognitive-semantic determination of the full meaningfulness of a cognition by sensibility, in turn, sharply constrains the scope of knowledge in the strict sense of “[scientific] knowledge [Wissen]”: objectively convincing true belief with certainty (CPR A820–22/B848–50).

Since strict or scientific knowledge requires truth, but truth-valuedness requires objective validity or empirical meaningfulness, then if a cognition is not objectively valid/empirically meaningful, then it cannot be either true or false, and therefore it cannot be strict or scientific knowledge.

In particular, it directly follows from this point that in the strict or scientific sense of “knowledge,” we cannot know things in themselves, either by knowing their nature, or by knowing whether they exist or do not exist; or in other words, we know a priori, by reflection on the cognitive semantics of human cognition, that we cannot have strict or scientific knowledge of things in themselves.

This is what I call radical agnosticism (Hanna, 2017b) — “radical,” because unlike ordinary agnosticism (epistemic open-mindedness or doxic neutrality about some claim C), it’s strict or scientific a priori knowledge about our necessary ignorance of things in themselves, and about our necessary inability to know or prove whether things in themselves (for example, God) exist or do not exist.

Given the truth of radical agnosticism, it directly follows that neither classical Rationalist metaphysics nor recent and contemporary Analytic metaphysics, since they’re based on mere thinking alone, and reasoning from mere logical or analytic possibilities, is capable of having strict or scientific knowledge, despite all their highly technically sophisticated, rigorous-sounding, dogmatic claims about knowledge of things in themselves.

Moreover, it also directly follows from radical agnosticism that any claim in speculative natural science that violates the cognitive-semantic constraints on strict or scientific knowledge — for example, any natural-scientific claim about positive noumenal entities belonging to microphysical essences, for example, molecules, atoms, quarks, neutrinos, etc., etc., insofar as these aren’t merely claims about the mental representations yielded by our use of experimental measurement devices (Hanna, 2021c) — is a truth-value gap; nence any form of metaphysical noumenal realism in natural science is deeply mistaken (Hanna, 2006: chs. 3–4).

So, I conclude that recent and contemporary Analytic metaphysics is nothing but a Copernican Devolution in philosophy, a disastrous regression to the long-discarded 18th century Leibnizian-Wolffian metaphysics, gussied up with a shiny veneer of modal logic, and mutely gesturing toward the natural sciences (Hanna, 2021c).

— Whereas, by a diametric contrast, a broadly and radically Kantian real metaphysics would constitute not only a Second Copernican Revolution in philosophy, but also a philosophy of the future (Hanna, 2021a: ch. XVIII, esp. section XVIII.6).


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Mr Nemo

Formerly Captain Nemo. A not-so-very-angry, but still unemployed, full-time philosopher-nobody.