In the messenger lectures, originally delivered at cornell university & recorded for TV by the bbc, feynman offers an overview of selected physical laws & gathers their common features into one broad principle of invaria...In the messenger lectures, originally delivered at cornell university & recorded for TV by the bbc, feynman offers an overview of selected physical laws & gathers their common features into one broad principle of invariance. He maintains at the outset that the importance of a physical law isn't "How clever we are to have found it out, but.