I find the question of whether solidarity is a virtue difficult to answer. True, John Paul II described it as such: “It is above all a question of interdependence, sensed as a system determining relationships in the contemporary world, in its economic, cultural, political and religious elements, and accepted as a moral category. When interdependence becomes recognized in this way, the correlative response as a moral and social attitude, as a "virtue," is solidarity.” (John Paul II, Sollicitudo Rei Socialis, Section 37). Given the definition of virtue related by Father Conners—“a stable disposition, a habit that disposes one to act in a certain way” (Lecture 7)—I can imagine it as virtue.
The fuzzy part for me is this “question of interdependence, sensed as a system determining relationships”. In Person and Act, Bishop Wojtyla conceptualizes solidarity as part of “participation”: “The attitude of solidarity is a ‘natural’ consequence of the fact that man exists and acts together with others” (Karol Wojtyla, Person and Act (English Critical Edition), page 401). Here the focus is on acting together, which does belie some foundational interdependence. The critical point, I think, is that the concept of solidarity includes also the “common good” in addition to interdependence: “[Solidarity] is also the basis of the community in which the common good correctly conditions and evokes participation, and in which participation correctly serves the common good, supporting and realizing it.” (Ibid.). If we think of the “common good” as described by Pope John XXIII—“the sum total of conditions of social life which allow people, either as groups or individuals, to reach their own perfection more fully and more easily” (Father Conners, Lecture 7; cf Gaudium et Spes, Section 26)—then solidarity is an attitude of community rather than a dyadic relationship such as marriage, where one thinks of the personalistic norm.
I think, then, that solidarity is a virtue, one of practicing the attitude of the “common good”. The disposition is not just the good of the other, as in charity, but rather the good of those in the “community”, those who share something in common. Thus, it is based in the koinonia of God as Father and Creator: “However, in trying to achieve true development we must never lose sight of that dimension which is in the specific nature of man, who has been created by God in his image and likeness (cf. Gen 1:26). It is a bodily and a spiritual nature, symbolized in the second creation account by the two elements: the earth, from which God forms man's body, and the breath of life which he breathes into man's nostrils (cf. Gen 2:7).” (John Paul II, Sollicitudo Rei Socialis, Section 29). This practice of this attitude of God as Creator is the basis for solidarity since it must incorporate the related attitude of commonality and connectiveness with other beings in the cosmos.
Solidarity is different from the virtue of charity, then, in that while their foci are similarly dyadic operationally, its domain is the larger Creation rather than the “other”—I practice charity with another individual, I practice solidarity with all of Creation. I believe this relationship is similar for justice, as well, which is similarly dyadic. While all three virtues are greatly interrelated, the virtue of solidarity focus on the awareness of and the respecting of the commonality of all beings through the Fatherhood of God.
