Why are we conscious? The answer lies in other animals’ heads

It’s easy to think human conscious experience is unique, but a better understanding of consciousness’s mysteries comes by tracing it back in the evolutionary tree

By Alison George

THE smell of coffee, the blue of the sky, the anticipation of seeing a loved one: it is impossible to imagine our lives without the vivid conscious experiences of our every waking moment. And yet they have vexed philosophers for centuries. “The nature of consciousness is extraordinarily difficult to define,” says Eva Jablonka at Tel Aviv University in Israel.

It was once thought of as an immaterial force, a “ghost in the machine” separate from physical reality. Today, however, many neuroscientists argue that our felt experience is simply the product of our brain’s inner workings. That makes the question of “why?” loom large. Many actions controlled by the brain occur unconsciously, beneath the level of our awareness. Why make exceptions?

Grasping this means thinking outside our own box, says Anil Seth at the University of Sussex, UK. “Human consciousness is not the only form of being conscious,” he says. We tend to emphasise conscious experiences that make us think we are better and smarter than other animals, like our ability to recognise ourselves in a mirror, he says. “This is not very helpful.”

The absolute fundamental of consciousness – having an actual experience of things – is something seemingly shared by many other organisms. “In my view, there are grades and varieties of awareness, and there is no principled dividing line about which – SHAZAM! – the light of consciousness is turned on,” says Daniel Dennett at Tufts University in Massachusetts.

With a broader view of consciousness, we can look back along the tree of life to get an idea about its earliest glimmers. Jablonka, together with Simona Ginsburg at the …