Tocqueville believed that it was through the doctrine of self-interest rightly understood that liberty is preserved in a democracy. Tocqueville insisted that socialism is materialistic, and a socialist society denies the existence of the soul; American democracy maintains a balance between the needs of the body and the soul. Self-interest rightly understood is animated by religion, and it is religion that prevents democracy from devolving into socialistic tyranny. For Tocqueville, socialism is concerned only with the pursuit of wealth, which gratifies only physical desires; but democracy is concerned with the pursuit of prosperity—real human flourishing—which balances the needs of body and soul. The doctrine of self-interest rightly understood is the key to striking that balance.