Many have been sceptical of Freud's claim that unconscious desires control our lives. Yet studies show the conscious brain processes only a tiny fraction of the brain as a whole. Are hidden desires and secret thoughts driving our actions, or is our conscious brain in full control?

Richard Bentall is a clinical psychologist and author of Doctoring the Mind and Madness Explained. He is a leading critic of biological explanations of mental illness and the pharmaceutical industry. He teaches at the University of Liverpool.

Here he speaks to the IAI about fantasy, disgust, cognitive behavioural therapy, and the “two brains” of every human being.

In the Hidden Desires and Secret Thoughts debate, you argued that there is such a thing as the unconscious realm. How can we know that?