A Puzzle Concerning Local Symmetries and Their Empirical Significance

A Puzzle about Laws, Symmetries and Measurability

I describe a problem about the relations among symmetries, laws andmeasurable quantities. I explain why several ways of trying to solve it will not work, and I sketch a solution that might work. I discuss this problem in the context of Newtonian theories, but it also arises for many other physical theories. The problem is that there are two ways of defining the space-time symmetries of a physic...

A Puzzle concerning Matter and Form

Empirical consequences of symmetries

There is something of a tension between two aspects of symmetry in physics. On the one hand, there is a widespread consensus that ‘two states of affairs related by a symmetry transformation are really just the same state of affairs differently described’: that is, that if two mathematical models of a physical theory are related by a symmetry transformation, then those models represent one and t...

Gravitational observables and local symmetries.

Using a recent classification of local symmetries of the vacuum Einstein equations, it is shown that there can be no observables for the vacuum gravitational field (in a closed universe) built as spatial integrals of local functions of Cauchy data and their derivatives.

Some Unexplained Metabolic Actions of Pituitary Hormones with a Unifying Hypothesis Concerning their Significance †‡

The elucidation of the nature and actions of the adenohypophyseal hormones has been a challenging problem which has been yielding to attack only very slowly. It has been recognized for some time that there are several adenohypophyseal hormones at least one of which, growth hormone or somatotropin, has general systemic metabolic actions."7 All the others, corticotropin, thyrotropin, follicle-sti...