 The first approach to the Indifference Principle looks for a wider range of physical symmetries, including especially the symmetries associated with a change of coordinate or unit. This approach, developed by Jeffreys (1946) and Jaynes (1968, 1973), yields a consistent, somewhat surprising answer 1/2 (rather than 1/3 or 1/15) to the question in the Square Case. See  supplement C  for some non-technical details.