  I describe some insight obtained from a lattice calculation on the
possibility that the light scalar mesons are \qbar^2 q^2 states rather than
\qbar q. First I review some general features of \qbar^2 q^2 states in QCD
inspired quark models. Then I describe a lattice QCD calculation of
pseudoscalar meson scattering amplitudes, ignoring quark loops and quark
annihilation, which finds indications that for sufficiently heavy quarks there
is a stable four-quark bound state with JPC=0{++} and non-exotic flavor quantum
numbers.
