I've heard gases are made of atoms, not quantum particles or waves.

but…

taby said:
expertise.

just no. So not sure.

But i have another question: Does the quantum slit experiment proof that choice is not optional?

Well, that's the thing. if a photon were a gas, then it would go to explain its ‘weird’ behaviour in the double-slit experiment. My old idea was that perhaps spacetime is plastic, but it doesn't seem so.

Also, I find your answers insightful, with expertise.