Ever since at least Quanta Cura and Rerum Novarum (1891), Catholic social doctrine reacts and comments on the "revolutions" that the world is going through, from industrialization to globalization, to the rise of financial capitalism and consumer society. These issues have taken on greater urgency in light of the populist movements sweeping Europe and the United States, which are forcing a reconsideration of the liberal order, at least as it has existed over the past half century. The current pandemic has only intensified the urgency of these questions.

But the English-speaking Catholic world has been somewhat at a disadvantage in these debates. Much of the work surrounding nineteenth-century social encyclicals is not in English and is hard to find. But terms like “social justice” and “subsidiarity” have a history, and Thomas Behr tells part of that history in his important book on Luigi Taparelli, a Catholic thinker who advocated a Thomistic natural law argument approach to politics. "Taparelli was the first Catholic theorist to explore the relationship between natural law and subjective law", writes Behr, "identifying the origin of the latter in the moral compunction deriving from the former, applied in concrete social reality".

Taparelli (1793-1862), Italian Jesuit, was co-founder of the Vatican newspaper Catholic civilization  and the influence of his work is evident in all papal social encyclicals, including his elaborations on social justice and the principle of subsidiarity. His main work, Theoretical Treatise of Natural Right Based on Fact has never been translated into English.

Behr places Taparelli between natural rights thinkers including Hobbes and Locke on the one hand, and democracy theorists such as Tocqueville and Raymond Aron on the other. In the background, of course, loomed the aftershocks of the French Revolution, right at its peak when Taprelli was born and which ushered in the rise of the secular state, hostile to religious beliefs. The theorists of the social contract who divined absolute rights from the state of nature were mistaken for Catholic social thought.

The Catholic conception of rights is different because it is based on a different conception of the person. We have rights from our nature as human beings, but Catholic thought sees rights as ordered to higher goods. Our right to exercise our rights is constrained not only by our historical circumstances and those of our particular society, but also by conscience and “the clarity and usefulness of a chosen action in relation to the pursuit of the highest good. … The more directly related to the highest good, the stronger the claim to right.

This is why certain rights are 'inalienable': they are inescapable requirements of order, of the orientation of the intellect towards truth and of the aspiration of people within society for the ultimate good.

In other words, we have rights to to do something, not simply to exercise those rights in any way we subjectively want and desire.

Thus, for Catholic social thought, the political community is not a place where each of us enjoys our individual political goods, protected by a "neutral" state to which we surrender our personal right to violence against others for violating our rights in exchange for protection in those rights. Rather, "[society] has as its aim the perfection of the individuals who compose it, an aim which is the common good of all associations, from the family to the State".

The role of "associations" is crucial here, and Behr carefully examines Taparelli's analysis of the concept of subsidiarity. Following Aristotle and Thomas Aquinas, Taparelli started from the fact that human beings are social creatures. Taparelli was a critic of the "absolutist, centralizing, bureaucratizing modern state" and thought that the defense of "inferior" associations was both necessary and part of a just political order. This type of political structure would protect assets such as religious freedom and private property. But he turned those protections into what he called a "hypotactic society," which he rendered as "subsidiarity."

Subsidiarity appears for the first time in the encyclical Quadragesimo anno(1931), and means that the more direct forms of association should manage the matters within their competence, unless they can and should be referred to a higher authority. This understanding comes directly from the work of Taparelli and Behr explains how Taparelli saw all associations in a society, public and private, working together for a common good. This principle echoes both the "little platoons" of society described by Edmund Burke and Tocqueville's astonishment at the various democratic institutions he saw forming in America. These institutions best protect people from rampant individualism – since we have overlapping obligations to our various groups – and from statism, since so much can be done locally or privately. This is also how we should understand social justice, a term Behr credits Taparelli with coining it.

The nineteenth century saw a number of European Catholic thinkers who worked to reflect and adapt Catholic teaching to modern industrial and political conditions. Behr has provided a welcome and solid introduction to one of the most important.