  Very recently the IceCube Collaboration has reported an observation of 28
neutrino candidates with energies between 50 TeV and 2 PeV, constituting a
4.1$\sigma$ excess compared to the atmospheric background. In this article we
investigate the compatibility between the data and a hypothesized unbroken
power-law neutrino spectrum for various values of spectral index \Gamma >= 2.
We show that \Gamma ~ 2.3 is consistent at the ~ 1.5$\sigma$ level with the
observed events up to 2 PeV and to the null observation of events at higher
energies. We then assume that the sources of this unbroken spectrum are
Galactic, and deduce (i) an energy-transfer fraction from parent protons to
pions, and (ii) a way of discriminating among models which have been put forth
to explain the "knee" and "ankle" features of the cosmic ray spectrum. Future
IceCube data will test the unbroken power law hypothesis and provide a
multi-messenger approach to explaining features of the cosmic ray spectrum,
including the transition from Galactic to extragalactic dominance.
