[sjaak]

If it were rational, it would also be falsifiable.

Let me ask you: what would have to happen for you to rescind your belief?

Also; at the risk of starting a discussion about religion: you haven't developed a logical argument by saying "universe is complicated -> deity". You've only moved the problem of "who or what created X" up one level to the deity. Who created the deity?

[andrewjl]

Rationality itself is not falsifiable, it relies on axioms that must be assumed true in order to work.

Edit: Treating rationality as something real as opposed to just a (very useful) figment of our imagination, i.e. something like a variant of Platonic Realism, is no different from any other religion.