[imheretolearn]

> For a heuristic to be good, it needs to have a clear domain of when it applies and when it doesn't.

I see your point. I believe both of us are saying the same thing albeit using different words. In this case, the domain would be the context in which the aphorism is used, which is exactly what the 3rd point in my parent comment says. As with everything, the context is equally important. When you take anything out of context, there is a high probability that it won't hold. Simply stating an aphorism, without understanding the context is only half knowledge and not actionable which inadvertently reduces the signal.