This discussion seems to have devolved into simply a discussion of microeconomics, although some have mentioned such issues as production, growth, and distribution. Let me note more generally that if one takes at all seriously aggregation problems, aka the fallacy of composition (which applies to many things besides the usual old textbook Keynesian investment story), what is going on at the level of individual choice, whether it is constrained optimization or robotized slavery or whatever, may have little to do with a variety of aggregate (or macro) phenomena that economists surely do study and take seriously, unless of course one insists on the supreme reality of the representative agent model, which I do not personally. So, this is another reason why the Robbins definition is at best limited, however useful it may be for large portions of economics. Barkley Rosser