To respond to the topic in general, there is nothing that could disprove creation (hypothetically) except for a device that could reverse the flow of time, make us able to see God, and take us back to the time the world came into being.
As for the more recent topic about "knowing," DogmaHunter declares God to be unreal by stating that it's impossible to "know" Him as a demonstrably real person.
Well, that's an interesting thought.
How do you demonstrate the reality of somebody?
If I tell you that I know my mother, you'll most likely believe me. And even if you don't, there's no reason for you to assume my mother doesn't exist. Besides, your knowledge and experience tells you that in order for me to exist, my mother must also exist.
What about my sister? Let's just say (hypothetically) I have no pictures, written documentation, or any other "verifiable evidence" of my sister's existence. Can I still know her even if I can't demonstrate her existence to you? Could you, if you wanted, believe that there's no such person because of my lack of ability to demonstrate her existence to you?
See, what's termed "demonstrably real" means "able to be verified in a way that seems reasonable to me based on my personal knowledge and experience." Unfortunately, that precludes anything that the speaker has no personal knowledge or experience related to so long as he or she does not want to believe in its existence. Which also means that if, for whatever reason, he or she decided that all the books ever written about the Roman Emperor Nero, Alexander the Great, Napoleon, and countless others were mere works of fiction, he or she could write each of these historical figures off as not being "demonstrably real" as well.