Probably all the books I've ever written have been efforts to define the boundaries of humanity.
Fred SaberhagenThe human mind is generally far more eager to praise and dispraise than to describe and define.
C.S. LewisThe human race is a zone of living things that should be defined by tracing its confines.
Italo CalvinoThe measure of life is not defined by how much you are earning, but how much you are giving back.
Debasish MridhaThe ability of humans to read meaning into patterns is the most defining characteristic we have.
Eleanor Catton