Some arts, however, are based on examination, that is to say on the knowledge and proper
appreciation of things, as for instance astronomy,
which demands no action, but is content to understand
the subject of its study: such arts are called theoretical.
Others again are concerned with action: this is their
end, which is realised in action, so that, the action
once performed, nothing more remains to do: these
arts we style practical,
and dancing will provide us
with an example.