If you don't kill them all how can you possibly win?
I know you're being squirrelly, but I'll answer anyway for those who don't know.
You can win by:
Conquest (eliminating all other players)
Domination (owning 75% of the territory, which often happens before conquest unless you're razing the cities)
Culture (get 3 cities up to "Legendary" culture status before anybody else manages to win)
Spaceship (complete the Spaceship, which requires a lot of advanced techs as well as a good industrial base)
Points (the game ends at a set date - if that date arrives, and you have the most points, you win! Points are simply a measure of population, happieness, technologies, territory, and everything else, combined into a total score.)