Das Ganze ist mehr als die Summe seiner Teile. The whole is more than the sum of its parts. This is the guiding principle of Gestalt psychology. Its more precise form is Das Ganze ist etwas anderes als die Summe seiner Teile, the whole is something other than the sum of its parts.
Max Wertheimer, Kurt Koffka and Wolfgang Köhler worked together on the theory from 1910, first in Frankfurt and later in Berlin.
The sentence is often credited to Aristotle. In his Metaphysics, Aristotle wrote that the whole is something besides the parts.