At the beginning of his short book Why Not Socialism?, G.A. Cohen asks the reader to think about a group of friends going on a camping trip together. He doesn’t describe anything out of the ordinary. The friends find a site and set up a tent. Some of them fish, some of them cook, they all go on hikes, and so on.

What Cohen wants the reader to notice is that the way this trip is run looks a lot like how socialists think society should be run. The pots and pans and fishing poles and soccer balls, for example, are treated as collective property — even if they belong to individual campers. When the fish are caught and cooked, everyone gets to partake equally of the result of the collective effort, free of charge. Cohen’s hypothetical campers act this way not because of anything especially noble about them, but because this is how any group of friends would act on a camping trip.

To make the point more sharply, he invites us to imagine a far less normal camping trip — one that’s run according to the principles of a capitalist market economy. One of the campers (Sylvia) discovers an apple tree. When she comes back to tell the others, they’re excited that they’ll all be able to enjoy apple sauces, apple pie, and apple strudel. Certainly they can, Sylvia confirms — “provided, of course . . . that you reduce my labor burden, and/or provide me with more room in the tent, and/or with more bacon at breakfast.”