Is science infinite? Can it keep giving us profound insights into the world forever? Or is it already bumping into limits, as I argued in The End of Science? In his 2011 book The Beginning of Infinity physicist David Deutsch made the case for boundlessness. When I asked him about consciousness in a recent Q&A he replied: “I think nothing worth understanding will always remain a mystery. And consciousness (qualia, creativity, free will etc.) seems eminently worth understanding.”

At a meeting I just attended in Switzerland, “The Enigma of Human Consciousness,” another eminent British physicist, Martin Rees, challenged Deutsch’s optimism. At the meeting scientists, philosophers and journalists (including me) chatted about animal consciousness, machine consciousness, psychedelics, Buddhism, meditation and other mind-body puzzles.

Rees, speaking via Skype from Cambridge, reiterated points he made last month in “Is There a Limit to Scientific Understanding?” In that essay Rees calls Beginning of Infinity “provocative and excellent” but disputes Deutsch’s central claim that science is boundless. Science “will hit the buffers at some point,” Rees warns. He continues:

There are two reasons why this might happen. The optimistic one is that we clean up and codify certain areas (such as atomic physics) to the point that there’s no more to say. A second, more worrying possibility is that we’ll reach the limits of what our brains can grasp. There might be concepts, crucial to a full understanding of physical reality, that we aren’t aware of, any more than a monkey comprehends Darwinism or meteorology… Efforts to understand very complex systems, such as our own brains, might well be the first to hit such limits. Perhaps complex aggregates of atoms, whether brains or electronic machines, can never know all there is to know about themselves.

To read more, click here.