# Why universe is so perfectly made for us? [duplicate]

I am very eager to learn that, "Why universe is so perfectly made for us?" Or our universe is just stable by chance?

## marked as duplicate by John Rennie, AccidentalFourierTransform, sammy gerbil, Qmechanic♦Aug 14 '18 at 19:12

I will not go into this in any detail but the de Sitter vacuum or spacetime is not perfectly stable. Quantum gravitation with string theory works well with anti-de Sitter spacetimes that have negative vacuum energy. String/M-theory does not like de Sitter spacetimes with positive vacuum energy. Remember the bosonic string or type I has a negative ground state. The observable spacetime is approximately de Sitter to within $10^{-5}$ in anisotropy, and has been since dark energy dominance. Our de Sitter world is then maybe some sort of freak or something generated out of an anti-de Sitter spacetime. Cumrun Vafa has coined the term "swampland" to describe this situation, where cosmologies may exist that have quantum fields inconsistent with gravity.