The human universe: Does consciousness create reality?

Samuel Johnson thought the idea was so preposterous that kicking a rock was enough to silence discussion. “I refute it thus,” he cried as his foot rebounded from reality. Had he known about quantum mechanics, he might have spared himself the stubbed toe.

Johnson was responding to Bishop Berkeley, a philosopher who argued that the world was a figment of our minds. Could he have been right?

With its multiverses and cats both alive and dead, quantum mechanics is certainly weird. But some physicists have proposed that reality is even stranger : the universe only becomes real when we look at it.

This version of the anthropic principle (see “Was the universe made for us?“) – known as the participatory universe – was first put forward by John Archibald Wheeler, a heavyweight of 20th-century physics. He likened what we call reality to an elaborate papier mâché construction supported by a few iron posts. When we make a quantum measurement, we hammer one of those posts into the ground. Everything else is imagination and theory.

For Wheeler, however, making a quantum measurement not only gives us an objective fix on things but changes the course of the universe by forcing a single outcome from many possible ones. In the famous double-slit experiment, for example, light is observed to behave either as a particle or as a wave, depending on the set-up.