# Events, Laws of Nature, and Invariance Principles

## Abstract

It is a great and unexpected honor to have the opportunity to speak here today. Six years ago, Yang and Lee spoke here, reviewing symmetry principles in general and their discovery of the violation of the parity principle in particular’. There is little point in repeating what they said, on the history of the invariance principles, or on my own contribution to these which they, naturally, exaggerated. What.I would like to discuss instead is the general role of symmetry and invariance principles in physics, both modem and classical. More precisely, I would like to discuss the relation between three categories which play a fundamental role in all natural sciences: events, which are the raw materials for the second category, the laws of nature, and symmetry principles for which I would like to support the thesis that the laws of nature form the raw material.

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## Reference

- 1.Chen Ning Yang, The law of parity conservation and other symmetry laws of physics; Tsung Dao Lee, Weak interactions and nonconservation of parity,
*Nobel Lectures, Physics 1942–1962*,Elsevier, Amsterdam, 1964, pp. 393–403 and pp. 406–418.Google Scholar - 2.See, for instance, A. C. Crombie,
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