Participatory planning replaces impersonal competitive market pressures with conscious, socially responsible cooperation, and leaves individuals and collectives free to pursue their own conceptions of the good life subject only to the constraint that others have equal opportunity to do so. Certainly compared to a world economy integrated by international markets for goods and capital, a world-wide system of participatory planning would yield more diverse local outcomes. The only differences it would eliminate are those due to economic exploitation and domination. While this may be the best way to take advantage of the potential benefits of international specialization while making world economic affairs democratic and equitable, there would still have to be a transition from a world of historically distinct participatory economies to a world-wide participatory economy. And during this transition international cooperation among participatory economies would be something different than participatory planning.
Different economies can exchange goods and services, productive resources, or productive knowledge.
Suppose our distinct participatory economies began by only wanting to trade goods, but wanted to do this consistent with their principles of economic democracy, equity, and ecological sustainability. Particularly if productive knowledge and resources were immobile, there would be benefits from international specialization of production according to comparative advantage. Moreover, there would be a range of terms of trade that gave each economy net positive benefits, and by varying the terms of trade between the limits of the true social opportunity costs of different goods in different countries, the benefits from specialization and trade could be distributed between two economies in any way desired. If the terms of trade were determined by market forces, a number of problems would arise. Market decision making is undemocratic.