  We show how the well known patterns of masses and interactions that arise
from spontaneous symmetry breaking can be determined from an entirely on-shell
perspective, that is, without reference to Lagrangians, gauge symmetries, or
fields acquiring a vacuum expectation value. To do this, we review how
consistent factorization of $2\rightarrow 2$ tree level scattering can lead to
the familiar structures of Yang-Mills theories, and extend this to find
structures of Yukawa theories. Considering only spins-$0$, $1/2$ and $1$
particles, we construct all the allowed on-shell UV amplitudes under a symmetry
group $G$, and consider all the possible IR amplitudes. By demanding that
on-shell IR amplitudes match onto on-shell UV amplitudes in the high energy
limit, we reproduce the Higgs mechanism and generate masses for spins-$1/2$ and
$1$, find that there is a subgroup $H \subseteq G$ in the IR, and other
interesting relations. To highlight the results, we show the breaking pattern
of the Standard Model $U(1)_{EM} \subset SU(2)_L \times U(1)_Y $, along with
the generation of the masses and interactions of the particles.
