“These new media have made our world into a single unit,” Marshall McLuhan observed in 1960, when he made the case for the emergence of a “global village”. Meanwhile, in the half-century since McLuhan’s meditations, scientists and philosophers alike have become increasingly occupied with the study of consciousness — what it is, how it works, and how it shapes our sense of self.

In Consciousness: Confessions of a Romantic Reductionist (public library), neuroscientist Christof Koch — “reductionist, because I seek quantitative explanations for consciousness in the ceaseless and ever-varied activity of billions of tiny nerve cells, each with their tens of thousands of synapses; romantic, because of my insistence that the universe has contrails of meaning that can be deciphered in the sky about us and deep within us” — explores how subjective feelings, or consciousness, come into being. Among Koch’s most fascinating arguments is one that bridges philosophy, evolutionary biology and technofuturism to predict a global Übermind not unlike McLuhan’s “global village,” but one in which our technology melds with what Carl Jung has termed the “collective unconscious” to produce a kind of sentient global brain:

The ever-increasing complexity of organisms, evident in the fossil record, is a consequence of the unrelenting competition for survival that propels evolution. It was accompanied by the emergence of nervous systems and the first inkling of sentience. The continuing complexification of brains, to use Teilhard de Chardin’s term, enhanced consciousness until self-consciousness emerged: awareness reflecting upon itself. This recursive process started millions of years ago in some of the more highly developed mammals. In Homo sapiens, it has achieved its temporary pinnacle. But complexification does not stop with individual self-awareness. It is ongoing and, indeed, speeding up. In today’s technologically sophisticated and intertwined societies, complexification is taking on a supraindividual, continent-spanning character. With the instant, worldwide communication afforded by cell phones, e-mail, and social networking, I foresee a time when humanity’s teeming billions and their computers will be interconnected in a vast matrix — a planetary Übermind. Provided mankind avoids Nightfall — a thermonuclear Armageddon or a complete environmental meltdown — there is no reason why this web of hypertrophied consciousness cannot spread to the planets and, ultimately, beyond the stellar night to the galaxy at large.

The rest of Consciousness traces Koch’s groundbreaking work with physical chemist Francis Crick (who, along with james Watson, discovered the double-helix structure of DNA) and explores how science has attempted to reconcile the hard physicality of the brain, the most complex object in the known universe, with the intangible world of awareness, populated by our senses, our emotions, and our very experience of life.