to continue what Erik said:
everyone does know how to fight. Most everyone knows how to make a fist and/or flail their arms around in a fashion that could hurt or injure someone (perhaps even themselves?) if needed, but few people have the courage and instinct to act on that if needed.
Reminds me of one of my favorite quotes, by Uesugi Kenshin:
"Those who cling to life die, and those who defy death live."
I guess we might train to defy death (as long as possible, anyways), then?
Something to reflect on,