John Maurice Clark was a practical economist. He emphasized real-life, dynamic models of economic activity that he developed from the static models of earlier economists. In particular, he continued and further developed the work of his father, John Bates Clark, always acknowledging the importance of his foundational work in the field.
John Maurice Clark studied market morality, especially in the behavior of trusts and monopolies. In his work, he was able to develop valuable concepts that proved useful in the field of economics. One of these was "workable competition," which was based on his belief that perfect competition is unattainable, a concept that later formed the basis of antitrust laws. However, such laws have not always been successful, and some, including Milton Friedman, concluded that they do more harm than good.
Later, Clark came to the realization that psychology and the social sciences offered understandings of human behavior that would greatly enhance economic theories. However, the problem with the economists' understanding of competition and antitrust laws, according to Unification thought, is not so much that economics has not included insights from the social sciences (although more would no doubt be beneficial), but that human nature since the Fall of Man has been inherently flawed. It is not the perfect competition that is unattainable, but perfect human nature has been unattainable. In the ideal, where human beings achieve their true potential as individuals, and in society learn to live for the sake of others, competition would naturally become "perfect"—providing the best products at reasonable prices for consumers while also allowing producers to achieve success.
From this Unification perspective, although Clark was correct in his realization that understanding of human nature is needed to develop better economic theories, it is change in human nature, removing the selfishness and allowing people to achieve their individual potentials that will allow the market to function harmoniously, bringing satisfaction to all.