How do black holes destroy information and why is that a problem?
> The important thing is that all evolution equations that we know of are time-reversible.I've heard this before, but it's so surprising to me, when one of the simplest mathematical operations - addition - is not reversible. e.g. if a+b=4, you can't infer the values of a and b (beyond their linear relationship). This non-injectivity is a kind of summarising, with less information, where more than one state maps to one.So "evolution equations" (reality) are not like addition; state changes never summarise.