Nothing as far as we would describe "nothing". I guess he is happy to wait for evidence to prove the existence of some or other god or something. Maybe an alien race that we would regard as gods etc.
Who said that the only other possibility was an intelligent race and/or being?
We should try to avoid being victims of using the argument of ignorance ourselves. Even if only options that we're aware of might not be the explanation ultimately supported by evidence, there can be explanations that we've never even heard of, let alone considered. Not to mention, can you examine and confirm that the "nothing" you're defining is truly nothing?
I'm just saying that we can't use a term that claims absolute certainty(as in "there's nothing there") that we aren't absolutely certain about. It's logically impossible for us to ever
know that "nothing" exists, as we can't know definitively that what we're examining or testing is in fact "nothing".