The charge of ambition for a slice of the lucrative self-help market can’t be rejected out of hand, but I think that Harris has the same problem everyone else has in discussing human consciousness and its relationship to a deeper dimension: we have have always called it the ‘spiritual’. This appears to contradict materialist assumptions and is too edgy for comfort.
I am surprised that Harris even uses the word. The classic ‘samkhya’, which is more of a finesse than a philosophy, produces an ersatz reclassification of the ‘ALL’ under the rubric of (???) spiritual materialism. But that ‘in principle’ unification (which is apparent in writers like Ouspensky on Gurdjieff, and J.G. Bennett) doesn’t really find the real science behind the trick method that so elegantly resolves the mystery, with a new jargon, but one that makes a powerful point.
In the final analysis we can simply adopt the language of consciousness itself, and leave behind the ‘spiritual’. We can also adopt a set of philosophic concepts created by Kant, and more clearly Schopenhauer: they show how the distinction between material and spiritual is in part a confusion of the phenomenal and noumenal. This raises the questions of the nature of consciousness in the construction of reality.
Here’s another attempt to materialize consciousness: