At some point all perception of the nature of existence as to deal with Faith.Wether you like it or not. You know you exist but cannot explain why and scientists cannot offer any evidence to explain why.
Why does there have to be a "why" to our existence?
It's very likely that things just are, and some people struggle to grasp the concept of us existing for no actual reason.
We're born, we live, we die. That is all we are 100% certain of.