纯粹贸易理论认为，来自自由贸易的经济效应和福利收益与来自劳动力的自由流动的经济效应和福利收益之间是替代关系，前者不会因为后者而得到强化。
As pure trade theory shows, the economic effects and welfare gains resulting from free trade are substituted, not enhanced, by those of free movement of labor.