Probability permeates much of physics. It appears in quantifying errors in every measurement, in the dynamics of stochastic processes, in statistical mechanics as a way of coping with the vast amount of variables, and even intrinsically in quantum mechanics. At first glance the use of probability may seem natural and even `obvious’, but things get much more lively when you realise that it is still not settled what a probability is. Different interpretations of probability affect the meaning of all the areas that it touches.
This material supports a second and third year advanced physics unit at Macquarie University.
In these notes I will take the view that probabilities are a measure of plausibility and probability theory is the extension of deductive logic to incomplete information. This view follows Laplace, Jeffreys, Cox, and Jaynes.
Status: In development. These notes are very much a work in progress and an exploration of the topic. They may change radically in the future. Lecture notes are available as mindmaps here: /map/probably-physics/.