I’ve suggested previously an analogy between the surgeon and the editor: We both cure with the knife.

There is a further comparison. Every time an editor goes into a text, he is like a surgeon opening up a human body; there is always a hazard of injuring something that was healthy to start with.

This has been succinctly stated by Erin McKean, a lexicographer and the chief consulting editor for the Oxford American dictionaries, in McKean’s Law: “Any correction of the speech or writing of others will contain at least one grammatical, spelling, or typographical error."

You can see more of what she thinks at her blog, Dictionary Evangelist.