Palmer Joss: [Ellie challenges Palmer to prove the existence of God] Did you love your father?
Ellie Arroway:What?
Palmer Joss:Your dad. Did you love him?
Ellie Arroway:Yes, very much.
Palmer Joss:Prove it.

— Contact

Faith is an intangible.  It is not something that can be proven.  It is something that you feel, not something you count and describe mathematically.  Trying to impose a rational standard of evidence into something that is not subject to rational evidence is worthless.

On the flip side, faith is not science, and should not be a substitute for it.  I can believe in my religion and trust in science at the same time, but they are separate fields of study.  Science cannot model and describe the human soul and its interactions with God, but saying “God made it that way” when asked “Why does this work like this?” of “How did this happen?” is a cop-out.