Prehistoric images speak to us more evocatively than any other element of the archeological record: colorful, vibrant paintings of horses, of bison, of a panoply of animals and humans that often seem alive and in motion. And yet there is a dimension of unreality about them... The images seem plucked from life... often arranged chaotically to our eye, frequently superimposed... sometimes apparently incomplete.... There is an enigma in these images, a profound challenge to our understanding of the past.

Origins Reconsidered: In Search of What Makes Us Human (1992)