When a person enters an unfamiliar space for the first time, such as a new habitat – a tropical or a taiga forest biome, for example – they will not recognise it as the world where they belong and which they have come to understand and accept as normal. Only very slowly and with intense effort can we humans teach ourselves that there is in fact order in this confusion; only by resolute application do we learn to distinguish and classify objects and understand the meaning of terms such as ‘space’ and ‘shape’. Instead, a visitor to a habitat new to them is afflicted by visual chaos – forms and colours, a muddle of new imprints, none of which seems to bear any relationship to the familiar landscape of home. We know that early global travellers...