One of the things that often puzzles people about developments in Church teaching is that they cannot see how the Church gets from where it was to where it is. Because of this, many imagine that the developments of doctrine are just sudden eruptions in which a Pope or Council just capriciously changes its mind.
Nothing could be further from the truth. The Ents of Rome typically take forever and a lot of hooming and homming before they finally formulate a conclusion to their decades- and centuries-long deliberations over stuff. Witness, for example, how long it is taking the Church to make a final statement about Medjugorje. Or the three centuries it took the Church to formulate the Nicene Creed. Or the 15 centuries it took for the Church to define the canon of Scripture. As Mike Flynn once remarked, the Church is not the Rapid Response Squad.
So Allen does us a favor by showing us all the theological homework and argumentation that has been going on in the Church for the past 40 odd years as environmentalism has pushed to the fore of our consciousness.
Some might ask, “Isn’t this a novelty since it’s only about 40 years old?” Nope. The formulation of teaching into a coherent whole is that recent (since it was only in the mid to late 20th century that people began to realize that there was a real threat to the natural world in unbridled human destruction being visited on nature). But the roots of the Church teaching stretch back centuries. The awareness that human sin can damage creation is as old as “cursed is the ground because of you;/in toil you shall eat of it all the days of your life” (Ge 3:17). In the same way, the Church’s social doctrine begins with Rerum Novarum, a mere century ago. That doesn’t mean it is a novelty. It means that only in the late 19th century had our thinking developed to the point that people were beginning to ask urgent questions about things like the relationship between economics and politics, the nature of capitalism, the arguments about communism, and so forth.
At any rate, the piece is very valuable in showing the long slow process of deliberation as the Church formulated the teaching now on display in Laudato Si.