Problems of Analytic Idealism

On Bernardo Kastrup’s consciousness-only ontology

Sender Spike
3 min readSep 16, 2023

In the abstract of his dissertation, Analytic Idealism: A consciousness-only ontology, Bernardo Kastrup (2019) writes, “This thesis articulates an analytic version of the ontology of idealism, according to which universal phenomenal consciousness is all there ultimately is, everything else in nature being reducible to patterns of excitation of this consciousness.

Right in that very first sentence is a clear testimony that Kastrup’s approach is merely a rehashing of ancient ideas based only on a rather naive, albeit complex, intellectual understanding. Not direct knowledge. Nevertheless, and setting all such subjective claims aside for a moment, it is indubitable that Kastrup’s ontology is build upon the same problematic assumption as physicalism — it searches for a fundamental phenomenon.

As Kastrup elaborates while addressing the natural order objection, “Under physicalism, the laws of nature are seen as irreducible causal patterns somehow built into the fabric of the cosmos. It is the dynamic unfolding of these patterns that leads to the order and complexity we see around ourselves. Under idealism, such irreducible causal patterns are posited to be somehow built into universal consciousness itself, instead of an objective fabric of spacetime. Yet, beyond this distinction, they are the same patterns that physicalism entails, as inherent to consciousness as physical laws are allegedly inherent to the fabric of spacetime. Idealism poses no extra difficulty than physicalism in this regard.

Now, Kastrup gives an accurate description of idealism (also in general terms) stating that, “[n]aturally, idealism is not solipsism. […] idealists take other people seriously as legitimate sources of reported experiences and views, not just as figments of one’s own imagination. Moreover, idealists acknowledge that there is a world outside and independent of their personal […] psyche, […] They simply do not acknowledge that this world is ontologically distinct from consciousness itself. Indeed, by acknowledging that implies a world outside their own personal mentation, idealists look upon this world in a way entirely compatible with naturalism and scientific inquiry.

However, in essence, one could argue that Kastrup’s consciousness-based monistic idealism is basically indistinguishable from physicalism.

After all, Kastrup is also clear on his position that “there is a strong sense in which, as far as human cognition is concerned, empty space is universal consciousness, the contents of space being excitations of universal consciousness. Moreover, since space is simply a facet of spacetime, […] it is closer to the truth to think of spacetime as universal consciousness than as a scaffolding occupied by universal consciousness,” and that, “unexcited universal consciousness must still have intrinsic properties — otherwise there would be nothing to eventually get excited.

Yet, even physicalism is well aware of the fact that space-time is emergent. But, while physicalism leaves the question, “from what?” unanswered, Kastrup simply swaps (or equals) space-time with consciousness and is done with it. This, however, does not solve the fundamental problem: if consciousness is phenomenal, as Kastrup maintains, it must be observable on some level, and it does not matter if it is fundamental (or emergent as per physicalism), in the state of excitation or unexcited.

Furthermore, and that’s a much more serious problem, consciousness is demonstrably (although only on a subjective level) devoid of any properties and attributes whatsoever, and the impossibility to directly experience it, while it can be in fact attributed to its unexcited state (which is however permanent and, for a lack of better word, superimposed), does not preclude it from being known (by itself) in its unexcited, pure state. In fact, consciousness as such can be known only “unexcited.”

So it follows that, while I certainly agree that consciousness is, indeed, that which we can call fundamental, it definitely cannot be phenomenal and it certainly does not have intrinsic or other properties. And that pretty much falsifies Kastrup’s ontology, though not on a basis of lack of explanatory strength (which he very briefly proposes), but simply due to incorrect initial assumptions.

Case closed.