It was as a young man and I was standing at the World Heritage listed Head Smashed in Buffalo Jump in North America. It is a site that celebrates the hunting culture of the Native Americans prior to the introduction of horses. Part of the cultural centre had a display that described where the native tribes lived over the centuries. What was fascinating was the sweep and swirl of the tribal movements. Initially it was slow, as they relied on foot transport. But then something amazing happened. There were surges and violently rearranging tribal arrangements as the introduction of horses revolutionised the Native American lifestyle.

I was amazed at how such small changes have the power to fundamentally alter everything these people had known about life. It suggested that the "world" that we understand was not as real or as fixed as I might imagine. What do we believe to be a fundamental truth now that will be discarded tomorrow?