SOLVING THE MYSTERY OF CONCIOUSNESS / THE ECONOMIST

Mind over matter?

Solving the mystery of consciousness

A new book by Michael Pollan explores the puzzles of the mind

Photograph: Marco Giardini/Millenium

“AFASCINATING BUT elusive phenomenon: it is impossible to specify what it is, what it does, or why it evolved. 

Nothing worth reading has been written on it.” 

That is how “The International Dictionary of Psychology” described consciousness in 1989. 

Michael Pollan’s excellent new book serves as a paginated retort to that last claim. 

The author, an American journalist, is best known for his work on food and diet. 

(His pithy distillation of decades of research—“eat food, not too much, mostly plants”—is the crème de la crème of dietary advice.) 

More recently he has been writing about mind-altering drugs, from psychedelics such as magic mushrooms to opium and caffeine.

There has been a boom in books exploring consciousness, especially in animals. 

Perhaps it is because of the questions AI raises about what counts as life; or perhaps people are becoming more concerned about animal welfare. 

The latest, “A World Appears”, focuses on what David Chalmers, an Australian cognitive scientist, has dubbed the “hard problem” of consciousness: namely, how human beings and other organisms experience things subjectively. 

This question has been occupying philosophers and scientists for centuries. 

One recent survey counted more than two dozen competing theories. 

Rather than pitch his own favoured explanation, Mr Pollan’s book offers a well-reported tour of several theories. 

Academic philosophising is not always known for being page-turning. 

But Mr Pollan has a journalist’s eye for the surprising and intriguing.

Think it sounds boring to watch grass grow? 

Not in Mr Pollan’s account. 

A group of scientists is advancing the striking claim that even plants have consciousness—or at least might exhibit something rather like it. 

One researcher puts corn plants in a metal maze used to test the intelligence of mice and rats, then watches as their roots navigate towards fertiliser buried in one corner. 

Another, watching a video of a bean plant looking for a pole to grow up, speculates that, like bats and dolphins, plants use echolocation to explore their environments. 

Anaesthetic chemicals, which shut down consciousness in animals, seem to have an effect on plants: an anaesthetised Venus flytrap will not close its leaves over an insect. 

If an anaesthetic is a drug that removes consciousness, what exactly is it removing in plants?

“A World Appears” covers more familiar ground, too, such as a different batch of scientists hoping to create artificial consciousness in a machine (and even some who think they have already done so). 

Mr Pollan is willing to push back against those he interviews when he thinks they are making unjustified leaps. 

At one point he offers a lucid critique of the widely held assumption that biological brains are analogous to electronic computers.

Sometimes Mr Pollan even makes himself part of the experiment. 

For a while he wears a device that beeps at random intervals, prompting him to note down exactly what his subjective experience was at that particular moment: such as, “A beagle, off leash, is walking towards me on the sidewalk.” 

It sounds simple. 

But soon doubts creep in. 

Is wearing the device subtly affecting his thinking? 

What counts as subjective experience, and what counts as mere context for that experience? 

Catching himself in the act of experiencing turns out to be frustratingly difficult.

So does the challenge of answering the hard problem. 

For though the book is well-written, richly researched and a pleasure to read, it does not offer any firm conclusions. 

Consciousness researchers are like cosmologists, notes Mr Pollan: they are unable to step outside the precise thing they are studying. 

In fact, it is worse than that: cosmologists can at least agree on what their measurements show. 

But the hard problem is hard precisely because of its subjective nature. 

There is simply no way to step into someone else’s head and check that their experience of the world matches yours.

“A World Appears” leaves you with a universe of questions and theories. 

Consciousness is about information processing, says one researcher. 

Or perhaps it is a way for organisms to choose between competing priorities, others assert. 

All of this is, by any standard, quite heavy stuff. 

It is a mark of Mr Pollan’s skill as a writer that it never feels that way.