Was at least the first life form created?

[Tiberius]

Actually, just to correct something Eilonnwy:

It's fairly simple, you posit a claim, you have the burden of proof. You reject a claim, then you don't have the burden of proof, it doesn't matter when you you've used the word "believe" or not. Basic logic.

If you posit a claim, you have the burden of proof. If you provide the proof, and someone rejects the claim, they have the burden of proof.

A person who doesn't have the burden of proof has the benefit of assumption, but once the burden of proof is fulfilled, the claimant has the benefit of assumption, and the burden of proof is passed on (to anyone who disputes the claim further).