Siméon Denis Poisson Quote
In many different fields, empirical phenomena appear to obey a certain general law, which can be called the Law of Large Numbers. This law states that the ratios of numbers derived from the observation of a very large number of similar events remain practically constant, provided that these events are governed partly by constant factors and partly by variable factors whose variations are irregular and do not cause a systematic change in a definite direction.
Statement of Poisson's law also known as the Law of Large Numbers (1837), as quoted by Richard Von Mises (1957). Probability, Statistics and Truth. Allen and Unwin. p. 104-105.