Thesis advisor: Jeffrey Bloechl / According to Catholic social doctrine, there are two principles which serve as foundational pillars of social thought and action: the dignity of human being and the primacy of the common good. Each human person has unique and endless worth in the eye of God, since “God created each human person in His image, in the image of God he created humankind, male and female. He created them” (Genesis, 1: 27). God creates all things and wanted them to participate in His glory and happiness (well-being). Thus, by their nature, all human beings want to be happy. To reach happiness is “something final and self-sufficient and the end of our actions” (NE 1097b20), but we should not forget that by nature man is a part of the greater order. How can one defend both the dignity of the human person and the primacy of the common good? To defend the dignity of human person the first question must be answered what is meant a human person, since the ways in which we understand ourselves as persons have direct effects on the ways in which we organize ourselves collectively in the political communities. To answer what is a human person we will understand how Maritain makes the distinction between individual and person, and what it is that constitutes a human person. It leads to understand the whole human being, soul and body, is a person. Man is as a part of the greater order. According to Aristotle and followed by Aquinas, every creature is only a part of the whole perfection of the universe, just as one instrument in an orchestra is a part of the whole perfection of the harmony. “Society is a whole composed of persons is to say that society is a whole composed of wholes” (Evans and Ward, The Social and Political Philosophy of Jacques Maritain, p. 85). Because the relationship between the common good and the dignity of the human person is the relationship of our dignity of finality and our dignity of nature. We distinguish between the human acts and the acts of human being in order to understand the notion of Aquinas’s the human act. Then, we will understand why Maritain defends natural law as an antidote for a secular society and present crisis of pluralist society. According to Maritain, the deepest result of the crisis from the modern to the present time is man’s natural community in the natural law and his innate ordination to the transcendent as the source of ultimate value have been casted into doubt. Thus, the only appropriate way to reconcile the common good and my good is to turn God into my private good as a kind of a good infinitely shareable, as if there were commensurability between my finite and infinite goodness. To make this reconciliation into the present age, “you must love your neighbor as, like yourselves,” ordered to a common good. / Thesis (PhD) — Boston College, 2022. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Philosophy.