As the Philosopher notes, the reason for an exchange is demand or need. The gods do not engage in exchange, because they do not need anything. Further, the Philosopher notes that economics is the art of wealth-getting. The getting of wealth is necessary for the right management of the household, that is in order to maintain the community men seek wealth as succor for men’s needs. It is then human need that provides the foundation for economics or the seeking after wealth.
There are a number of questions that we can proceed toward and we can consider them in term. Men have many needs, but not all are the concern economic. What needs does economics concern? This will then in turn help to answer the question of what is wealth, economic value and property.
The needs that are the immediate concern of economics are those most basic concerns, namely food, shelter, clothing, etc. Men will seek first to feed themselves and provide their own shelter. However, man has also a basic need for community and family that is not the subject of economics. Indeed, the community is principal of economics, that is there is no economy where there are no men. A man alone will seek after his own needs, but this is an aberration and not the principal of economies, but only community and men already together. A man is only ever found alone after having been separated from a community and an economy.
Therefore, there are certain political goods, which are not the subject of economics. Peace and the political good is not the subject of economics save in so far as economics is ordered to the fulfillment of the political good. Economics then finds is end and purpose in the political good, but the political good is not wealth, but wealth its accumulation and use is ordered only toward the political good. Economics is not the art of peace getting, but wealth getting toward the end of peace and order of society. Economics is then subordinated to politics in that economics is ordered ultimately to the common good of politics.
Wealth then is that which is subordinated to the production of political goods, peace, order, etc. This concerns the necessities of life which produce peace and order in supplying for human need that man may not be anxious about their life in ways that would upset peace and order. The starving man is much more irrational in his actions and cannot be lived with until his starvation has been relieved. His life is in the balance and will take drastic measures to preserve himself, even violence and other acts contrary to the common good. As the Angelic Doctor teaches should he take another’s food in such as state, he takes what belongs to him by nature and this returns to the universal destination of all goods in the succor of human needs. As Zippy Catholic notes, this is not an exception to private property, but the acceptance that there is a limit to human authority and in particular over external objects or property.
We may further see that wealth concerns external things, while political goods are internal or common. Wealth then concerns those external things which can be used to succor human needs, such as food, shelter and so on. A further question would regard the nature of things that succor man’s higher and more immaterial needs, such as health, knowledge, virtue and so on.