This is precisely why I don't trust people who aver without receipts to show. Open the schools, goddammit!
Until I see some reasonable evidence that smaller process size cannot exist, i just see lazy people getting angry that someone disagrees with them. All of this "burden of proof" bullshit, aping like you're in some kind of formal debate rather than a conversation with a stranger, just screams "emotional asshole who can't deal with someone disagreeing with them and never learned how to engage in basic conflict resolution when they had the ability to engage in good faith and chose not to".
Y'all deserve all the mockery society can afford. I'm at least honest in that I see conflict is what we need more than ever if only to put people like you in your place.
I love condescension that is so petty it's laughable. As the commenters said below there are very well-understood precedents/principles that allow me to conclude "no" here eg
https://en.m.wikipedia.org/wiki/Russell%27s_teapot
So no it's not "impossible to have any degree of certainty in asserting the non-existence of something", we actually have a whole branch of mathematics dedicated to exactly that (it's called probability and statistics).