Laws should be changed when new science proves them to be founded on bad science
There's a big problem in that bad laws are difficult to change. Laws supposed grounded in the scientific knowledge of that time they were made should be modified or even removed if new scientific data--evidence and facts--prove the old reasons for the law to be invalid. The problem is people get used to something and then don't want to change. For some the law gives them a justification, even if that justification is grounded in falsehood or even lies. Nearly 50 years ago some of the arguments that were used to justify the Roe V. Wade decision, to legalize abortion, have been proven to be wrong. Much of the scientific justification used was that fetuses didn't feel and couldn't be considered viable, "facts" that today are easily proven wrong through medical equipment that was science fiction in the 1970s but which is science fact today. But the argument now is that a woman should have the choice to end the life growing in her womb. Of course, liberals won...