Flights in the Mindscape

Review of Bernardo Kastrup’s "Analytic Idealism in a Nutshell"

To watch Peter’s virtual discussion with Bernardo, click here.

At the Gates

Bernardo Kastrup is a rather unique figure, with hybrid heritage and hybrid education: being now Dutch but with Danish-Portuguese filiation, early Brazilian inculturation, and having doctorates in both computer engineering and in philosophy. After working at CERN (the European Organization for Nuclear Research) and the Philips Research Lab, amongst other notable organizations, he switched focus to the deeper field of Metaphysics, completing a PhD at the Dutch Radboud University on what he calls ‘Analytic Idealism’. This review is based solely on his most recent publication, which aims to be a concise, clear, simplified version of that thesis – his book, Analytic Idealism in a Nutshell: A Straightforward Summary of the 21^st Century’s Only Plausible Metaphysics (Iff Books, 2024).

For context, I shall first briefly explain the types and the history of Idealism generally. I shall, secondly, provide a swift summary of what the core of Kastrup’s Analytic Idealism actually is – i.e. describe Analytic Idealism in a Nutshell, in a nutshell – and then offer a critically-engaged broader summary. Thirdly, selected issues of interest will be emphasised: ‘Brains and Worms’ looks at the metaphysical limits of neuroscience; ‘Psychedelic Battleground’ asks whether psychedelics decrease brain activity whilst increasing mental activity; and ‘Porous Dashboards’ offers an alternative extended metaphor that pushes the relation of individual minds to Nature as one of continuity rather than alienation. All of this relates to how we understand consciousness and reality – a saga of metaphysics and empirical science intertwined with politics and history.

Idealism Generally

Generally, Idealism is the view that our reality is mental, not material/physical. There are numerous varieties of Idealism, including these core four:

1. Transcendental Idealism: Reality perceived and conceived is radically distinct from reality in-itself. Immanuel Kant’s (d. 1804) philosophy epitomises this position, where not only are the colours, sounds, scents we perceive merely mind-dependent, but even time and space are but projections of our minds. Kant calls our perceived reality Phenomena, and the reality that lies beyond our perception, reality-in-itself, Noumena. Noumena is unknowable to humans.

2. Absolute Idealism: Reality perceived and conceived is the same as reality-in-itself because reality-in-itself is mental. This was broadly-speaking the view of Schelling and Hegel, the latter of whom especially inspired the Absolute Idealism that was prevalent in Britain and America in the late nineteenth to early-twentieth centuries, arguably culminating in the work of F. H. Bradley (d. 1924).

3. Solipsism: One can only know that one’s own mind is reality. Though this view is often considered as a necessary doubt that one cannot expel, Bradley’s chapter on it in his masterwork Appearance and Reality (1893) offers a persuasive critique of its truth and necessity. Absolute Idealism in contrast asserts that a universal mind, ‘the Absolute’, rather than one’s individual mind is reality.

4. Platonic Idealism: Plato’s view that our physico-mental world is a shadow of the more fundamental and eternal realm of ‘Ideas’ – from the Greek Eidos (Ideal / Form).

Historically, in the West, Idealism became somewhat prominent amongst certain Renaissance thinkers, with the resurrection of Plato. It was renewed with the seventeenth-century Cambridge Platonists, and then, in the more modern forms, we see Idealism rise in the philosophies of Leibniz (d. 1716) and Berkeley (d. 1753). But it was the Idealism of Kant (d. 1804) that had a more profound influence on modern thought. Yet there were perceived problems with Kant’s Idealism that Fichte (d.1814), Schelling (d. 1854), and, most influentially, Hegel (d. 1831) sought to remedy, thus advancing their Absolute Idealism. (See, for instance, my old master’s dissertation on Schelling’s critique of Kant.)

Arthur Schopenhauer (d. 1860) also sought to advance Kant’s Idealism, but in a way distinct to the aforementioned Jena lot – with more emphasis on the primal drives than the rationality of reality – and it is Schopenhauer’s type of Idealism to which Kastrup mostly adheres. These predominantly German forms of Idealism had an artistic effect on Romanticism (especially via Coleridge and Wordsworth) in the early nineteenth century, and later in that century, academically, on the aforementioned British and American Absolute Idealist movement, which flourished from around 1875 to 1925.

But then Idealism appeared to die. There were many reasons for this, such as the logical development of Realism (that I shall return to in my analysis of Kastrup), but there were also political reasons such as the reaction to the First World War that fostered a somewhat anti-German and anti-nationalistic sentiment amongst the English-speaking world (especially against Fichte and Hegel). W. J. Mander, in his book British Idealism (2011), goes so far as to state that:

“Antipathy to the immediate past gave way to dismissal, as a version of the history of British Philosophy began to be taught that jumped straight from Mill [d. 1873] to Russell [d. 1970]. This had the result that even today most philosophers know nothing of British Idealism; it comes to them as a genuine surprise to learn of this ‘idealist aberration’ in the great British empirical tradition.” (ch. 15, p. 527)

In the twentieth century Idealism was kept alive by certain thinkers, such as May Sinclair (d. 1946), Hilda Oakley (d. 1950), and Timothy Sprigge (d. 2007). But it never regained its popularity. But now in the twenty-first century we are seeing its revival, and Bernardo Kastrup is offering his support.

The Nutshell in Nutshells

Let me begin here by stating that Kastrup’s ‘Analytic Idealism’, judged by this book alone, straddles, I would say, between the Transcendental and Absolute varieties of Idealism: Reality is radically distinct from its appearance, from how it is perceived (à la Kant) – but it is also radically similar, in so far as reality, like appearance, is also mental (à la Hegel).

Hazelnut—

Analytic Idealism in a tiny nutshell: We perceive reality in a particularly human way as a physical world. But reality-in-itself is very distinct from how we perceive it, and so reality-in-itself is not physical as such, but more akin to what we fathom as nonphysical: our minds. Reality is thus mental, and this mind of the universe exists as a simple, nonrational entity or domain of which our individual minds are dissociated parts, much like how our dream characters are dissociated from our overall selves. At the end of this dissociation, at death (and in certain altered states of consciousness), we awaken into this Mind-at-Large and become rather than perceive this greater reality.

Walnut—

Now follows a larger nutshell of Kastrup’s argument for the truth of Analytic Idealism, interspersed with some critical reflections.

A.—

There is a negative pole and a positive pole to the argument that Kastrup makes for Analytic Idealism. We begin with the negative. The world we perceive cannot be how the world actually is, appearance cannot faithfully represent reality. We humans have evolved to perceive the world in a particular way, other organisms will have evolved differently and thus perceive the world differently, even in terms of space and time. Kastrup employs the metaphor of an airplane’s dashboard against the metaphor of a transparent window for perception. Though the dials and displays in the cockpit give us information about the world – the temperature, light, height, velocity, etc. – it is nonetheless encoded information.

The temperature outside is not identical to the actual thermometer dial, the sign is not the signified, the representation is not the represented, the appearance is not the reality. Furthermore, we cannot assume that our perception of reality is like a transparent window, i.e., that reality appears as it is, not only because different organisms have differently-evolved windows as above, but also, Kastrup argues, because of the fact that the unlimited complexity or entropy of reality could not be replicated as it is in ourselves without our constitution dispersing itself into that reflected unlimited entropy, into “hot meat soup” (p. 14). We must simplify our perceptions of reality to function – perception is necessarily abstraction.

B. —

Now comes Kastrup’s second negative move. We do not perceive reality as it is, but we do perceive reality as physical. Therefore, Kastrup argues, it is unlikely that reality is physical. That is, Physicalism is unlikely to be correct. As Physicalism is seen as an antithesis to Idealism, Kastrup seeks to fortify his argument against Physicalism both logically and sociologically. Logically, the Hard Problem of Consciousness is ushered in: Physicalism fails to explain how consciousness exists. Sociologically, Kastrup goes through a number of interesting theories as to why Physicalism was championed for reasons of power, relating, for instance, to the elevation of the bourgeoisie above the clergy, Industry and its scientific acolytes over the dominating Church – as Kastrup writes, “Physicalism is not a hypothesis motivated by evidence and clear thinking, but a philosophical side effect of a psycho-socio-political power game.” (p. 28) One could almost say that the book is more a critique of Physicalism than a promotion of Idealism, so vehement is Kastrup’s distaste for what is seen as the prevailing ideology of the West.

C. —

The third move in the argument for Analytic Idealism now begins the positive advance: from what the world is not like to what it is like. Kastrup writes that “we have every reason to believe that the real states of the world – which are external to, and independent of, our perceptual representations – are nonphysical, in the sense of not being amenable to description by physical quantities” (p. 19). My cup of tea is amenable to physical description (with its mass, diameter, volume, etc.), but my joy in the taste of the tea is not amenable to physical description (what is the weight of joy?). The argument now continues (somewhat tenuously here without sufficient argumentation) that what is not amenable to physical description is nonphysical: “endogenous experiential states … such as thoughts and emotions … are not amenable to description by physical quantities. As such they are nonphysical states” (p. 20).

So, the argument runs: Reality is Nonphysical, the Mental is Nonphysical, and now to tie the loose ends: therefore Reality is Mental – Idealism. This, however, commits the Fallacy of the Undistributed Middle: All R is N, All M is N, therefore All R is M – (consider R, M, and N instead standing respectively for sea, air, and nonsolid, for example). In other words, even accepting that Reality and the mental are nonphysical, it still does not of necessity imply that Reality is therefore mental (Idealism) – another logical possibility is that Reality is fundamentally neither physical nor mental (such as in Spinozism). Though Kastrup does not explicitly reveal this limitation, he does implicitly accept it: “I don’t know what it is like to be the real world out there. But our thoughts and emotions do provide proof of existence of the kind in question, i.e., nonphysical states. As such it is coherent to posit that the real world is constituted of nonphysical states” (p. 20, final italics mine). Essentially this means that even with the falsity of Physicalism, Idealism may be true rather than it must be true – an uncertainty standing in contrast to the avowed certainty at the end of the book’s subtitle declaring that Analytic Idealism is the ‘only plausible metaphysics’.

D.—

The next positive advance Kastrup makes is to distinguish individual minds from a universal mind. The latter he comes to call, after Aldous Huxley, Mind-at-Large. This is essentially, the mind of the universe, somewhat akin to ‘the Absolute’ of Absolute Idealism. But unlike Hegel’s rational Absolute, Kastrup’s Mind-at-Large is nonrational on the basis that it, unlike our individual minds, did not have to evolve “within the constraints of a planetary ecosystem that demands adaptability” (p. 58). Instead in Kastrup’s Idealism, the mind of the universe is “a comparatively simple and predictable mind; a spontaneous, instinctive, non-reflective mind” (ibid.). This is thus hardly a Pantheism, unless God has the mind of a goldfish.

E. —

Swimming down to the individual mind, Kastrup considers it a “subset” of the Mind-at-Large, in much the way that our dream avatars are subsets of our general minds. To differentiate my mind from the mind of the universe requires a boundary because “[w]ithout the boundary, we wouldn’t perceive the world, but instead be the world” (p. 103). In addition to the dream analogy, Kastrup employs the analogy of “alters”, alternate personalities of one human, that manifest themselves in Dissociative Identity Disorder. Humans are thus each alters of Mind-at-Large, but how far down does dissociated individual consciousness go? Kastrup goes as far as single-celled organisms, with their cell membranes acting as the represented limit of dissociated individuation (p. 110).

This categorizes him as a biopsychist rather than a panpsychist – in fact, one chapter is devoted to disparaging a particular form of panpsychism (“micro-constitutive panpsychism,” a form associated with the thought of Russell rather than the more plausible “panexperiential” form of Whitehead). I personally consider this proposed cell membrane limit somewhat arbitrary, preferring Leibniz and Whitehead’s view that the distinction between the “organic” and “inorganic” is a false dichotomy – even the ripples conceived as atoms and plasmoids have self-organisational properties, the latter even having a magnetic sheath membrane that individuates it. Regardless, bodily death means the end of the individuation, of the dissociation, of the alter, and thereby awakening, in the human case, from the dream self that is you. But as such it is not the end: “Death is but a change of perspective: the transition from perceiving the world to being the world” (p. 144).

Brains and Worms

Image: ikantani.com

One common retort against Idealism generally is that it makes the activity of the brain superfluous: what would be the need for the existence of “neural correlates of consciousness” if they were not to generate consciousness? But from an Idealist perspective, inversely, it is consciousness that generates the representation of the brain, the neural correlates of consciousness. And like all representations, they are merely abstractions (simplified, insufficient depictions). The so-called neural correlates of consciousness are, in Idealism, effects rather than causes of consciousness, representations rather than requirements. What we perceive as neural activity is here but the dashboard-encoded, simplified representation of the deeper conscious reality that is represented.

Thus, as the road sign is less complex than the city, so neural activity is less complex than the phenomenology with which it is correlated – there is more in the mind than in the brain. An interesting illustration Kastrup gives in relation to this is with regard to memory: it was observed (in 2013) that aquatic flatworms known as planaria can be taught to remember how to navigate a surface to find food. But then after suffering decapitation, thereby losing the neurons in their head, the worms can yet still remember this navigation some two weeks later when their heads had regrown, “contradicting the premise that memories are physically stored in (networks of) neurons” (p. 77). This is much in line with Henri Bergson’s (d. 1941) theory of matter and memory, and it is exciting to wait for further such experiments.

A subsequent point Kastrup makes is that neural correlates of consciousness can only capture the mentality that humans can report because they are conscious of them: conscious of their consciousness, that is, “metacognitive” states. Of course this means that the mental states we experience of which we are non-conscious (such as an unregistered distant ringing, a mild ache, a nagging worry, a suppressed desire, the subconscious in general), or which are not remembered, will not be reported and thus correlated to neural activity.

(One might add that, furthermore, non-human organisms’ states of consciousness are also non-reportable and therefore non-correlatable.) Only recalled human metacognition, not all mentality, can be correlated to neural activity. Consequently, the sought-after neural correlates of the mind are always insufficient for this reason as well as for the previous Idealist reason. This is not an attack on neuroscience, but the offering of an alternative metaphysical framework in which it can operate. Neuroscience need not be a Physicalist endeavour.

Psychedelic Battleground

If mystical states of experience are ineffable, as William James argued, then, like the subconscious, these states could neither be reduced to knowable neural correlates as they could not be reported in any, let alone sufficient, detail. Incidentally, William James himself argued that psychoactive drugs, specifically nitrous oxide, made him understand the Idealism of Hegel more clearly than his sober rationality permitted (“On Some Hegelisms,” 1892). Kastrup takes a different approach to defend the Idealist viewpoint from the current Physicalist assumption that underlies the thriving contemporary neuroscience of psychedelics.

In fact, Kastrup devotes a substantial section of his little book to defend his contention that psychedelics induce increased phenomenology by decreasing brain activity. This is first used as an argument against the dominant Physicalist doctrine of Emergentism: that the brain generates the mind, thus decreased brain activity in relevant areas must, under this metaphysical doctrine, lead to decreased mental activity. Yet the opposite happens, Kastrup claims, thus disproving Emergentism and thus Physicalism as such. The retort he considers is that psychedelics may decrease brain activity overall, but that the relevant neural activity for such consciousness must increase somewhere, “so the hunt is on for something in the brain that increases under the effect of psychedelics” (p. 41). He dismisses Robin Carhart-Harris’ answer, the “entropic brain hypothesis” as “implausible to the point of being ludicrous” (p. 42), where increased entropy (disorder) is said to cause increased phenomenology.

Increased entropy of course really means decreased order of activity. Kastrup takes issue with definitions of “information” amidst accusations of misinformation: After Kastrup argued for this decrease a few years ago, a spat ensued with each side accusing the other of lack of understanding, some claiming that no decreased activity has been found. I should like to see further experiments and hypotheses emerge to determine this issue, ideally with the neuroscientists separating their empirical findings from any metaphysical biases, as far as this is possible.

In Analytic Idealism, psychedelic-induced decreased brain activity would represent, as in death, the suspension of the dissociative mechanism that separates one’s individual mind from the Mind-at Large, from the mindscape of which we are parts. This temporary opening into the whole could explain certain reported mystical experiences of unity and nature-connectedness. This is somewhat in line with Huxley’s own theory, influenced especially by Bergson, that psychedelics (in his case mescaline, then LSD) halt the consciousness “reducing valve” of the brain thereby allowing the influx of Mind-at-Large. But Bergson was a Dualist (of sorts), not an Idealist, and decreased brain activity induced by psychedelics would also be expected under his unique metaphysical theory. Thus if decreased brain activity induced by psychedelics was solidly confirmed, this itself would not prove any definite metaphysical theory, though it might disprove one (Emergentism). I consider this an important area of further research, both philosophic and scientific, and it reveals once more the importance that psychedelic research can have upon consciousness research in general.

Porous Dashboards

As I argued in my recent recorded conversation with Kastrup, I consider it a False Dilemma to present the two options – a dashboard or a transparent window – as the only viable options of perceiving reality. Perhaps this dilemma only emerged because this is a brief synoptic book that has to skip certain details. Regardless, historically, Idealism advanced into a Realism (distinct from Kastrup’s meaning of “realism,” p. 2) because a third option was seen: that we see through a glass darkly, as it were – that we actually have a porous dashboard with coloured glass portholes and air vents in addition to the dials, to extend and fuse the metaphors. As such, the distinction is essentially that for Realism the difference between appearance and reality is not one of kind but of degree. With F. H. Bradley and then more explicitly in A. N. Whitehead’s “organic realism,” elements of external reality (and the past) are absorbed into, and thus constitute, the subject. Part of the process that is the “object” becomes part of the process that is the “subject.” The light process becomes the brain and body process, one extended event.

We are in this manner continuant with, rather than alienated from, Nature – a view encapsulated in the term, “process-relational metaphysics.” I find Kastrup is more Kantian in his harsh separation of appearance and reality, dashboard and sky, whereas I prefer a more Bradleyan Idealism-come-Realism where we cannot make the assumption that what is experienced is, at least in some cases, not identical to the experience itself. As Bradley argued, the separation of subject and object, of experience and experienced, is not itself a direct experience but a subsequent intellectual inference – we do not start with separation. Moreover, if, as Kastrup argues, external reality is mental in any case, it is hardly inconceivable that this external-mental would flow into and thus be the same (numerically and thus qualitatively) as the internal-mental. Denying this leads to strange conclusions such as Kastrup’s claim that “redness perceived represents another [mental] quality – which isn’t itself redness – out there in the world” (p. 126). That is to say, the experience of redness in us represents not redness out there, yet it does represent another mental quality instead.

Odd. Why not enhance parsimony and consider the quality to be identical internally and externally, thereby dissolving the sharpness of even that dichotomy (and also thereby refuting the necessity of Solipsism)? As Bradley writes, “I deny that the felt reality is shut up and confined within my feeling. … [A mental state] may remain positively itself, and yet be absorbed in what is larger” (Appearance and Reality, 1893, ch. 21). We absorb the external world as well as represent it. This view can still, however, be considered Idealism. As Bradley himself reflected, “'[w]hether [my philosophy] is to be called Realism or Idealism I do not know” (ibid., ch. 27). Even the organic realist Whitehead confesses in the Preface to Process and Reality (1929) that his “approximation to Bradley is evident”, and that his work may be “a transformation of some doctrines of Absolute Idealism onto a realistic basis” (p. xiii). I therefore say that I do not find Kastrup’s Idealism Realistic enough, in this specific, continuative, sense.

Final Approach

Kastrup’s book is an enjoyable read which throws up many fascinating questions and acts as an effective starter for those who have never read classic works of Idealism. Those classic forms are distilled and presented effectively, and fortified by contemporary scientific findings. I am broadly in agreement with Kastrup’s view, especially on the uselessness of Physicalism in explaining consciousness – but I maintain the following points of difference and contention: i) I do not accept the False Dilemma of having either a dashboard or a transparent window as regards perception, with preference for a third-way Realist metaphor of a porous dashboard: appearance and reality are not as separated as Kastrup here argues; ii) I do not accept without sufficient argument that what is not amenable to physical description is thereby nonphysical; iii)

The Fallacy of the Undistributed Middle in relation to reality, mentality, and the nonphysical, means that Analytic Idealism is not logically necessary, even though it may be correct and plausible; iv) I do not see the necessity of considering the cell with its membrane to be the end limit of subjective individuation, and as such, and for other reasons, I would prefer a panpsychism to a biopsychism, in line with Whitehead’s “panexperientialism”; v) I do not see the necessity of assuming that external-mental qualities are necessarily distinct from internal-mental qualities in all prosaic cases; vi) I would prefer further neuroscientific experiments and collaborative theorising to gain more decisive agreement as to the relation between psychedelic-induced mystical experience and relevant brain activity levels.

Of course, all of these points of contention are open to debate, and I am cognizant that it is easier to criticize a doctrine than to create one. Kastrup has done a marvellous job in bringing Idealism to a wider audience through his passion and intellect, and I hope and trust that he will continue to advance his fascinating thought.