  In statistical mechanics one packages the possible energies of a system into
a partition function. In number theory, and elsewhere in mathematics, one
packages the spectrum of a phenomenon, say the prime numbers, into a
$\zeta$-function or more generally into an L-function. These packaging
functions have symmetries and properties not at all apparent from the energies
or the primes themselves, often exhibiting scaling symmetries for example. One
might be able to understand those symmetries and compute the packaging function
independently of the actual packaging. And so one finds a way of putting
together objects into a package, and ways of discerning symmetries of that
package independent of the actual mode of packaging. This is a recurrent theme
of the Langlands Program as well. Packaging is also found in Weyl's asymptotics
and "hearing the shape of a drum" (Kac), the Schwinger Greens function in
quantum electrodynamics packaging the Feynman sum of histories, and more
generally in the Selberg trace formula.
