system
Given the following post, respond as if you're commenting on Reddit:
human
[Chemistry] Why is it unlikely that symmetrical molecules can turn plane-polarized light?
gpt
If you had *one* molecule, and *one* plane-polarized photon, and an extremely sensitive detector (way more sensitive than is probably physically possible), you might see that photon's plane of polarization rotated by an interaction with an achiral molecule.

The thing is though, there are lots of molecules and lots of photons, leading to lots of interactions. It's not that an achiral molecule can't affect the light in that way - it's just that there is no bias towards any particular direction. Each interaction is equally likely to rotate a photon's polarization plane clockwise or counterclockwise, so averaged out over many interactions you end up with no net rotation.