Believing that ET doesn't exist is as absurd as believing they've ever visited us.
Of course there is life out there, some of it intelligent, but the same laws of physics applies to them, as it does to us. The sheer vastness of our Galaxy & the distances involved, makes interplanetary travel completely impractical.
Sorry, but...deal with it, they're not here and never have been.
You do realize our understanding of physics is still primitive right? We just discovered gravity waves lmao, a basic pillar of the fabric of the universe.
Even our more concrete laws of physics are bent and even broken and we're just barely out of the horse and buggy age.
There exist special occasions where the universe up and does a magic trick that seems to be designed by an unjust, all-powerful entity dedicated to making scientists ask, 'What in the hell?'
www.cracked.com
^ that's right now imagine, 10, 20, 50,000 years from now.
We're clueless monkeys with cell phones that struggle to travel to our own moon, of course everything outside of that would seem impossible. Imagine telling scientists in the 1700s we'd even attempt a moon landing, you'd be burned at the stake if the wrong person heard your "impossible" ramblings.
The problem is your perspective is very apex oriented when the very foundation we've built is shaky at best. Not to mention we just started building it.
It's such a typical human way of thinking. "World is flat, flight is impossible, Europe is the only continent, the atmosphere is impenetrable, speed of sound cannot be broken, etc etc." --- you do realize the worlds greatest minds believed those things?
Keep in mind again, we JUST discovered gravity waves, lol. That's how primitive we still are.