They believe in reincarnation. But they don't believe in a caste system. This attracted a lot of laborers and the poorer classes to Buddhism because you could reach nirvana no matter what your wealth was. Anybody could do it. But Buddha, when he left that palace, first had to figure out things for himself. And he tried going to gurus and talking it out and debating and wandering the hills. He tried fasting, not eating food and seeing if that would lead him to some kind of enlightenment.