in quantum mechanics? What is this, religious talking?
Real engineers believe nothing
(about things, that is. We believe only in people).
Quantum mechanics is a theory, for the love of Pete. We think it works. Deterministic theory doesn't work.
Heck, furthermore: we do not think
it works, we can prove
it works... That's the litmus test, do not worry about people that denies experimental results, they might have a degree but they don't deserve it.
It took me almost forty years of reading physics and doing experiments to finally have a huge moment: that very day I understood that an electron is not
a small billiard ball. A billiard ball is a figment of my mind, made of a huge amount of matter, a human concept. I know, I know, that doesn't make any sense... keep reading physics, the day will come.
Finally, if you want to see quantum mechanics in action, simply put two fingers together and leave a narrow slit between them. Look through the slit. You'll see the diffraction pattern (small dark lines). There you have it.
Even my 9 years old little girl understands
quanta (she doesn't believe
in them, she has a good education). I was one day explaining to her something about matter and time and she answered: "oh, I see, dad. The universe is pixelated". Then she went to play dolls. Yeah, guys, the universe is pixelated.