Is consciousness real? Could it be just an illusion manufactured in the theatre of our minds? And what use i–– it is largely a scientific mystery. As we interact with the world, stimuli trigger physical processes in our body. Nerve cells transmit messages around the body and through the brain. But how do these physical interactions give rise to the conscious sensations we experience? Can we get conscious sensation from nerve cells alone? In this video theoretical psychologist Professor Nicholas Humphrey asks whether consciousness could all be an illusion. Could it be a mirage constructed in the theatre of our minds? Perhaps the questions we should ask are not centred on sensations themselves, but merely on the appearance of those sensations. And why does consciousness, in any form, exist at all? How did it evolve? The answer might lie in our social interactions. Consciousness elevates our interpretation of the world and the people around us. It alters our psychological profile and breathes joy into our experiences, and makes us value life itself. The Ri is on Twitter: http://twitter.com/ri_science and Facebook: http://www.facebook.com/royalinstitution and Tumblr: http://ri-science.tumblr.com/ Our editorial policy: http://www.rigb.org/home/editorial-policy Subscribe for the latest science videos: http://bit.ly/RiNewsletter