Galen

It is impossible that two bodies, which are characteristically behaving actively and passively, when they meet, behave simultaneously actively and passively, or that one does not behave actively, and the second - passively. If the bodies are equal in strength, then they are equally active and passive; if one prevails and is stronger than the other, it affects the passive; its activity grows and begins to be felt, and it itself will be almost or not at all passive.

Galen: Die Werke des Galenos.