Psychology, it’s said, has a long past but a short history. A popular version lists three stages.

First, around the turn of the 20th century, psychologists tried to capture the stream of conscious experience in the net of introspection. The behaviourists then declared the mind off limits, arguing that psychology should study observable behaviour rather than subjective experience. Finally, the emergence of computers spurred the cognitive revolution of the 1960s, which brought the mind back in from the cold, in a new science of information processing.

This narrative arc is appealing, but substantially wrong. Introspection was never a dominant method in psychology. Psychologists continued to study mental processes throughout the behaviourist dark age. And some argue the story leaves out a crucial fourth stage. Cognitive psychology may have made great strides in understanding the mind as computation – neuroscientists helping to figure out the brain’s hardware – but it failed to grasp something vital.

Review: A World Appears: A Journey Into Consciousness – Michael Pollan (Allen Lane)

Enter the study of consciousness – the subject of a new book by accomplished journalist and academic Michael Pollan. For the past few decades, philosophers, psychologists and neuroscientists have tried to redeem this once-taboo concept and uncover its secrets. That effort has been driven by the belief that mainstream cognitive science cannot solve the so-called “hard problem” of how and why subjective experience arises.

The study of consciousness has been enormously successful in attracting intellectual talent and public attention. Many specialist academic journals have been founded and blockbusters written. Distinguished scientists from other fields – Nobel Prize-winning biologist Francis Crick and physicist Roger Penrose among them – have beaten a path to this new scholarly El Dorado.

All this cerebral effort has been less than enormously successful. No consensus view has formed on the nature or underpinnings of consciousness, on what kinds of entity possess it, or even on how the field’s key questions and concepts should be defined. New theories of consciousness sprout faster than they can be weeded out by evidence – and philosophers continue to hold radically different views on its metaphysics.

Pollan’s book, A World Appears, wades into this morass in search of clarity. He is the author of numerous books on the intersection of nature and culture, with special emphasis on food, plants and........

© The Conversation