Why did Buddha reject Hinduism

The Buddha proposed 5 aggregates of clinging: form, feeling, perception, consciousness, and mental formations. If you look at any of them, you'll see that they all change: bodies change and grow older. Parts die. We shed skin, etc. This is very clearly not the same body that we had when we were younger. Our feelings change even faster: we feel pleasant one minute, unpleasant the next, and bored after that. So that fails the definition of a permanent, unchanging self. What about perceptions? Consciousness? Mental formations? They change rapidly, almost whimsically. It makes no sense to claim that any of them is a permanent self, or Atta. So we say, this is not me, this is not mine. As the chant goes: Sabbe sankhara anatta.

But did the Buddha teach not-self? Or did he teach no-self? The Canon, as far as I've studied it, does not mention the Buddha ever once saying that there is no Atman, or Atta. What he DID say, over and over again, was that those five aggregates of clinging are anatta, or not-self. The Buddha very carefully avoided making a definitive claim of there not being an Atman. A person can identify rather easily with that, and it becomes an object of clinging--a view of self, which is one of the lower fetters. However, it's very difficult to form a sense of self around the negation of this sense of self with the aggregates.

Source(s): Theravada Buddhist