Probably this is one of the oldest films posted at TDF. The Character of Physical Law are a series of seven lectures by physicist Richard Feynman concerning the nature of the laws of physics.
The talks were delivered by Feynman in 1964 at Cornell University, as part of the Messenger Lectures series. Their text was published by the BBC in 1965 in a book by the same name.
The lectures covered the following topics: The law of gravitation - an example of physical law, The relation of mathematics to physics, The great conservation principles, Symmetry in physical law, The distinction of past and future, Probability and uncertainty - the quantum mechanical view of nature, and Seeking new laws.
Watch the full documentary now (playlist - 6 hours)