Is anyone aware of a particularly good explanation of the general confounding issue (not the tank problem specifically) discussesd at the start of the article?

Is anyone aware of a particularly good explanation of the general confounding issue (not the tank problem specifically) discussesd at the start of the article? In a talk I'll give in about a month I will be briefly mentioning how confounding between two variables makes much previous research in my field wrong. Most people in my field will never have heard of confounding and I don't have much time to dedicate to this in the talk. Right now I am planning to say something like "If you make two changes at once, you can't know which caused the observed change in the output or the relative contributions of each input change."