  At this point in time, two major areas of physics, statistical mechanics and
quantum mechanics, rest on the foundations of probability and entropy. The last
century saw several significant fundamental advances in our understanding of
the process of inference, which make it clear that these are inferential
theories. That is, rather than being a description of the behavior of the
universe, these theories describe how observers can make optimal predictions
about the universe. In such a picture, information plays a critical role. What
is more is that little clues, such as the fact that black holes have entropy,
continue to suggest that information is fundamental to physics in general.
  In the last decade, our fundamental understanding of probability theory has
led to a Bayesian revolution. In addition, we have come to recognize that the
foundations go far deeper and that Cox's approach of generalizing a Boolean
algebra to a probability calculus is the first specific example of the more
fundamental idea of assigning valuations to partially-ordered sets. By
considering this as a natural way to introduce quantification to the more
fundamental notion of ordering, one obtains an entirely new way of deriving
physical laws. I will introduce this new way of thinking by demonstrating how
one can quantify partially-ordered sets and, in the process, derive physical
laws. The implication is that physical law does not reflect the order in the
universe, instead it is derived from the order imposed by our description of
the universe. Information physics, which is based on understanding the ways in
which we both quantify and process information about the world around us, is a
fundamentally new approach to science.
