The common behavior of mankind is the system of reference by means of which we interpret an unknown language.
Boxing and wrestling are evidence that mankind has not rid itself of all savage behavior.
When I observe other animals, I understand their behavior. I can't say the same for mankind.
All human behavior, all human motivations, all man's hopes and fears, were heavily colored and largely controlled by mankind's tragic and oddly beautiful pattern of reproduction.
From this observed behavior a major psychological truth about this race of forked destroyers may be deduced: that, just as nature abhors a vacuum, "mankind abhors equality."
Behavior is what a man does, not what he thinks, feels, or believes.
Mankind must put an end to war before war puts an end to mankind.
John F. Kennedy