The story of human civilisation begins around 10,000 years ago. This is when we evolved from isolated groups of hunter-gatherers into complex societies, setting aside our natural suspicion and becoming capable of living closely together with other people.
That ability to put our trust in strangers was only made possible through the development of societal norms – sets of shared rules designed to encourage prosocial behaviour and to discourage deviance. Philosophers call these norms ‘the