 A few years after Samuelson, Richard Musgrave introduced an alternative criterion, that of (non-) excludability (Musgrave 1959). As the name suggests, a good is excludable if and only if it is possible to prevent individuals from consuming it, to “draw a fence around it” as it were. Land is thus a good that is considered excludable, while streetlight is not excludable: if Bob pays for a streetlight to be installed, he cannot stop his neighbour Sally from benefitting from it.