Because I understand how energy has evolved and the stages required for it to evolve into beings that know and create and that the likelihood of the energy that makes up you will ever be part of another being that knows and creates. Sure your energy that makes up who you are right now came from somewhere else and has existed for 14 billion years ago and that it will continue to exist but it ain't likely to go into another being that knows and creates. Your consciousness will either continue to exist pursuant to some law we don't know about and can never prove or it will cease to be. I believe it is the former as I believe mind is the source for physical stuff. This is literally the fundamental distinction between materialists and spiritualists.
That'sonly proof that you know nothing because what you just said in unprovable nonsense.
It's called the 1st Law of Thermodynamics. Matter and energy cannot be created or destroyed. It only changes form. Can you tell me how the matter and energy that make up your being will be transformed into another being after you die?
Your belief of reincarnation is magical thinking.