My point is actually that it can be done more or less objectively in the most relevant cases, especially where the atmosphere is concerned. Tax the polluting ac

My point is actually that it can be done more or less objectively in the most relevant cases, especially where the atmosphere is concerned. Tax the polluting activity and use the taxes to exactly offset the pollution. If it can't be undone, or there wasn't any of that type of pollution in the atmosphere to start with, then it shouldn't be taxed--it should be banned. Sure, there's subjectivity in how we define which things are considered harmful enough to address as an externality or outlaw in the first place, but greenhouse gases, for example, are pretty cut and dry, and either way, it's a huge improvement over the current system (don't address externalities directly, create new big political programs that sort of address symptoms once they become big problems).