> not about which of the laws of physics are invariant under time reversal. If I recall from Brief History of Time, it's the combination of charge, parity, and

> not about which of the laws of physics are invariant under time reversal. If I recall from Brief History of Time, it's the combination of charge, parity, and time all together which are invariant. Some google searching also yields that time crystals were shown to disprove time symmetry/invariance.