David Spiegelhalter discusses how the work of amateur mathematician Thomas Bayes and statistician Ronald Fisher helped to shape the current thinking of probability.
The last episode in the series examines how humans perceive and experience time, investigating the internal body clock which tells people when to eat, drink, sleep and relax. The importance of accurately measuring time is explored in relation to human evolution, and there's a debate about whether mankind will ever be able to travel between past, present and future.
How the passing of time on Earth affects life on a variety of levels, from the daily opening of a flower's petals to the evolution of the horse. A swift journey through the seasons demonstrates how caribou spend most of their time on the move, while the flying squirrel's body clock, attuned to the rhythms of the Earth, is revealed to be the most accurate in nature.