Even in the case of minerals, modern physics (forget psychedelics) gives us reason to wonder if perhaps some form of consciousness might not figure in the construction of reality. Quantum mechanics holds that matter may not be as innocent of mind as the materialist would have us believe. For example, a subatomic particle can exist simultaneously in multiple locations, is pure possibility, until it is measured — that is, perceived by a mind. Only then and not a moment sooner does it drop into reality as we know it: acquire fixed coordinates in time and space. The implication here is that the matter might not exist as such in the absence of a perceiving subject. Needless to say, this raises some tricky questions for a materialistic understanding of consciousness. The ground underfoot may be much less solid than we think.

—Michael Pollan, How to Change Your Mind, Allen Lane, 2018