This episode continues the investigation into the nature of time. In particular it introduces two philosophical models of time, which are more in tune with scientific thinking. One is Newton's realist view of time. The other, in direct opposition to Newton, is the relational view of time. It was defended by Gottfried Wilhlem Leibniz (1646-1716) in the 17th century. Modern physics seems to be sympathetic to the relational view, at least according to some textbooks on the theory of relativity. I end this episode with a discussion of time in modern physics: the behaviour of atomic systems, and the behaviour of clocks in fast-moving reference frames (rockets) and gravitational fields (for example near or far away from the earth).

I explain that GPS would not work without taking the result of Einstein's Special and General theory of relativity into account. Einstein's theories have led to a revolution in our understanding of time, including the question of time travel.

Literature:

The material for episodes 10 and 11 is drawn from Friedel Weinert, The Scientist as Philosopher: Philosophical Consequences of Great Scientific Discoveries (2004) and The March of Time: Evolving Conceptions of Time in the Light of Scientific Discoveries (2013).