Should origins mean anything to us today?

Our discussion revolved around "rule of thumb". That, my professor said, has a negative source. People use "rule of thumb" all the time to talk about the general rule of something. Last night at fire training the instructor was talking about building construction. He said "the rule of thumb is..." It is funny that I heard it the very day we talked about it in class. I knew where rule of thumb origins had come from but others in the class had not heard of it.

The rule of thumb came from the time when you could beat your wife with a stick that was no bigger than the husband's thumb. She said that is such a negative origin, that the phrase "rule of thumb" should not be used. She then joked that if she had lived back then she would have married a guy with no thumbs. I can say I will not stop using it. I don't think that it should stop being used only do to its origin. If we stopped using things that came from a bad situation, then there are other things that people should not use today.

There are some people that say the medical advancements that we have gained due to the Nazi experiments from WWII should not be used because they were unethical. I don't buy that. I don't believe the end justifies the means, however we should not discontinue the use of things because people apply our standards of life to a different generation. That might sound a little like cultural relativism. I don't believe in that either. There are rights and wrongs that transcend cultures. But that does not mean that we should ignore things that help people, or phrases that may have come from a bad beginning.