  I construct lowest-energy representations of non-centrally extended algebras
of Noether symmetries, including diffeomorphisms and reparametrizations of the
observer's trajectory. This may be viewed as a new scheme for quantization.
First classical physics is formulated as the cohomology of a certain
Koszul-Tate (KT) complex, using not only fields and antifields but also their
conjugate momenta. Then all fields are expanded in a Taylor series around the
observer's present position, and terms of order higher than p are truncated.
Finally, quantization is carried out by replacing Poisson brackets by
commutators and imposing the KT cohomology in Fock space. This procedure is
consistent for finite p, but the limit p\to\infty leads to difficulties.
