While I enjoyed the nature of this book (survey-style books that explore a thorny question are some of my favorites), Pollan brushes by a major tension that's extremely relevant today: can AI truly be conscious? He states several times that the answer to that question is "no" or at least "not any time soon," but does so in a way that feels a bit disingenuous to a book otherwise intentionally critical of most theories. While he and the various scientists and philosophers he cites are willing to extend the possibility of consciousness, or at least sentience, along a broad biological spectrum (plants and single-celled organisms) and across several substrates (not just brains can be conscious), his prevailing conclusion is that a machine could still not be conscious. If the substrate doesn't matter, then it doesn't matter at all. Saying otherwise creates an arbitrary line that carbon-based systems can have consciousness, but silicon-based systems can't. Following those arguments to their logical conclusion, we end up committing to biological essentialism, property dualism, some story about why this particular arrangement of carbon is special in a way silicon can't replicate.

I recognize that this is the "hard problem" of consciousness, and that as a metaphysical phenomenon it may be structurally unsolvable given that we can only evaluate others' consciousness via subjective inference. Pollan's relative lack of criticality on this point is a low point in an otherwise solid book.

Three threads I'm pulling on next: William James on the philosophical limits of studying a stream from inside it; Damasio on feelings and the body as constitutive of consciousness and how it relates to trauma and experiences as somatic memory per van der Kolk's The Body Keeps the Score; and Kuhn's A Landscape of Consciousness.