But the idea of love is important, its the reason you the individual would more likely place yourself at risk legaly and physically to save that person.
Whats more likely, that you kill person trying to kill your wife or that you kill person trying to kill random guy on street as youy walk by?
You are doing it based on the idea of love and love resides in the head.
It does doesnt it, ravells?
We can all lust after a beutiful woman, thats physical. Yet love is more than that, its an idea, its in the head and in the heart.
And thats why you would kill or die or to protect her, not because of physical lust, thats easy enough to replace by finding another woman, but because of love - an idea.
And much the same works with religion and ideas, you do things to protect the outcomes of ideas you hold dear - even kill or be killed for them..
You wouldnt want a world without the idea of love, no?