>"Subsidy" carries a connotation of purposeful action to help something. Purpouseful action implies awareness and intention. Externality implies not yet recog

>"Subsidy" carries a connotation of purposeful action to help something. Purpouseful action implies awareness and intention. Externality implies not yet recognized. Having 2 words for similar concepts does not mean they are different concepts. "heavy" and "massive" are two different words but they convey essentially the same thing. I would agree that unrecognized externalities are not subsidies, say CO2 pollution before it was recognized, but then again since they were literally not recognized as externalities (yet). But the very moment CO2 pollution is recognized, the previously unrecognized externality is to be instantly viewed as a subsidy. History repeats itself, the first time as a tragedy, from then on as a farce.