Kastrup’s Analytic Idealism

Philosopher Bernardo Kastrup's “analytic idealism” is “a consciousness-only ontology” that has refocused attention, within the philosophical community and more broadly, on metaphysical idealism, that is, an idealism that is grounded in philosophical argument as opposed to promoted by religious tradition or spiritual belief. Kastrup's modern, analytic version of the ontology of idealism asserts “(a) phenomenal consciousness, as an ontological category, is fundamental; and (b) everything else in nature can ultimately be reduced to, or grounded in, patterns of excitation of phenomenal consciousness” (Kastrup, 2019). Thus, he proposes “there is only cosmic consciousness” (Kastrup, 2018), in that “spatially unbound consciousness is posited to be nature's sole ontological primitive” (Kastrup, 2017).

In Kastrup's idealism, human beings, along with all other living organisms, are but “dissociated alters of cosmic consciousness” (Kastrup, 2018) that are “surrounded like islands by the ocean of its mentation.” The inanimate universe we see around us, he says, is “the extrinsic view of thoughts and emotions in universal consciousness. The living creatures we share the world with are the extrinsic views of other dissociated alters of universal consciousness. A physical world independent of consciousness is a mistaken intellectual abstraction” (Kastrup, 2016a, 2016b).

Cosmic Consciousness and Dissociated Alters

Evidence that consciousness is not reductionist-materialist, Kastrup argues, comes from, among others, neuroimaging of brains in altered states induced by psychedelic substances. That these “unfathomably rich experiential states” correlate with significantly reduced activity in multiple brain areas is said to “contradict the mainstream metaphysics of physicalism for obvious reasons: experience is supposed to be generated by metabolic neuronal activity.”

He dismisses “the best physicalist hypothesis to explain psychedelic experiences” based on the idea that psychotomimetic drugs cause brain desynchronization, processes labeled “brain entropy,” “complexity,” “diversity”—which Kastrup interprets as “very straightforward: brain noise.” The “entropic brain hypothesis,” Kastrup says, is “a linguistic charade,” leaving mainstream physicalism unsupported as a viable metaphysics of mind (Kastrup, 2023). (Neuropsychopharmacologist David Nutt contends that “we don't need to adopt an untestable metaphysical worldview to explain the subjective richness of psychedelic experiences” and that neuroscience and neuroimaging research have resources to develop complete theories—for example, chaotic cortical entropy may “release the usual brake” that the cortex holds on sub-cortical structures, especially the emotion centers, liberating the amygdala and hippocampus from “top-down” inhibitory control [Nutt, 2023]. Kastrup counters that such disinhibition, if it were the case, should itself correspond to increased brain activity somewhere in the brain, which is not what is observed.)

Brain, Experience, and the Decomposition Problem

How to explain, under idealism, the correlation between inner experience and brain states? According to Kastrup, “the brain and its patterns of neuronal activity are not the cause of inner experience, but the image, the extrinsic appearance of inner experience. In other words, brain activity is what inner experience looks like when observed from the outside.” As such, he says, “the correlations ordinarily observed between patterns of brain activity and inner experience are due to the trivial fact that the appearance of a phenomenon correlates with the phenomenon.” And when this correlation is broken, as observed in the psychedelic state, the reason is that, “unlike a cause, the appearance of a phenomenon doesn't need to be always complete”—it can leave out much about the phenomenon it is an appearance of (Kastrup, 2023).

Kastrup maintains that idealism's key challenge is “to explain how the seemingly distinct phenomenal inner lives of different subjects of experience can arise within this fundamentally unitary phenomenal field.” This is called the “decomposition problem,” and it is the core problem Kastrup needs to address. Other challenges include “how to reconcile idealism with the fact that we all inhabit a common external world; why this world unfolds independently of our personal volition or imagination; why there are such tight correlations between measured patterns of brain activity and reports of experience” (Kastrup, 2019).

Kastrup's unabashed challenge to his metaphysical competitors is that an idealist ontology “makes sense of reality in a more parsimonious and empirically rigorous manner than mainstream physicalism, bottom-up panpsychism, and cosmopsychism” (Kastrup, 2018). He argues that an idealist ontology “offers more explanatory power than these three alternatives, in that it does not fall prey to the hard problem of consciousness, the combination problem, or the decombination problem, respectively.” (Panpsychists seem to be taking the challenge more seriously than do physicalists^[1] [Kastrup, 2020b; Goff, 2020].)

Given his consciousness-only ontology, Kastrup explores what might follow in two areas of high interest and continuing controversy: foundations of quantum mechanics and prospects for life after death.

Regarding quantum mechanics, he stresses the centrality of consciousness, making the startling but perhaps coherent argument that “the dynamics of all inanimate matter in the universe correspond to transpersonal mentation, just as an individual's brain activity—which is also made of matter—corresponds to personal mentation” (Kastrup et al., 2018).

Quantum Mechanics and Life After Death

Regarding life after death, Kastrup speculates that “the implication is that, instead of disappearing, conscious inner life expands upon bodily death, a prediction that finds circumstantial but [claimed] significant confirmation in reports of near-death experiences and psychedelic trances, both of which can be construed as glimpses into the early stages of the death process” (Kastrup, 2016a, 2016b).

Say this for Kastrup's analytic idealism: it expands and enlivens the consciousness debate.

Footnote

[1]. See the energetic, illuminating debate between idealist Bernardo Kastrup and panpsychist Philip Goff (Kastrup, 2020b; Goff, 2020).