[WalterBright]

Yeah, but we still don't learn from mistakes with well-known history behind them.

For example, I still hear from smart, educated people that we can stop illegal drug use by applying severe punishment to the drug suppliers.

[usefulcat]

It might be that knowledge of the past is necessary but not sufficient to avoid repeating previous mistakes.

The fact that some people lack knowledge (whether by choice or by accident) is hardly a compelling argument against its utility.