It is human instinct to sort and categorize. We are hardwired to discriminate and frame everything in binary black and white. It’s how our brains work. Migrant or refugee? Muslim or Christian? Them or us? Rather than reaching out to those who are different, we bond with those who are similar to ourselves. Rather than challenging our own thinking about the world, we endeavour only to confirm what we believe. The result is that the difference between polarized beliefs becomes ever greater. Dangerous possibilities arise. Through persistent binary thinking our capacity for rational and nuanced thought – seeing the grey, rather than merely black and white – begins to erode. ‘Black and White Thinking’ is an alarm call. It argues that by understanding the evolutionary programming of our binary brains we can overcome it, make sense of the world and in future make much subtler – and far better – decisions.