By elaborating on Albert O. Hirschman’s map of the rhetoric of reaction, which identifies the main theses of conservatism in its opposition to social change (perversity, futility, jeopardy), this chapter considers the first set of objections that might be put forward against intervention: perversity and futility. According to perversity objections, we should refrain from intervening because intervention will actually make things worse. According to futility objections, intervention should not be attempted because it is bound to fail, due to either structural or substantive limitations. It subjects these objections to Bostrom and Ord’s Reversal Test and identifies instances of status quo biases in them, providing us with additional reasons to reject them. It concludes that, at most, these objections suggest what the interventionist may easily concede: That intervention should be performed just in case it is informed and when the expected outcome is net positive for wild animals.

We motivate intersection homology theory by discussing how Poincaré duality fails on spaces with singularities. We see that one difficulty is the failure of general position, explaining why generalizations of general position will play an important role in the definition of intersection homology, which is a variant of simplicial or singular homology that recovers a version of Poincaré duality for singular spaces. We also discuss some conventions that will hold throughout the book and provide a quick overview of the difference between GM and non-GM intersection homology. We also provide a chapter-by-chapter outline of the rest of the book.

We introduce (GM) intersection homology, beginning with a discussion of perversity parameters. The treatment of intersection chains begins with the simplicial version, followed by PL (piecewise linear) intersection chains, and then singular intersection chains. As PL homology is less common than simplicial and singular homology, we provide the necessary background. We provide definitions, examples, and the most fundamental properties of intersection homology.