Our behavior is different. How often have you seen a headline like this?--TWO DIE ATTEMPTING RESCUE OF DROWNING CHILD. If a man gets lost in the mountains, hundreds will search and often two or three searchers are killed. But the next time somebody gets lost just as many volunteers turn out. Poor arithmetic, but very human. It runs through all our folklore, all human religions, all our literature--a racial conviction that when one human needs rescue, others should not count the price.
Robert A. HeinleinI'll give you an exact definition. When the happiness of another person becomes as essential to yourself as your own, then the state of love exists.
Robert A. Heinlein