In this article, I consider Bernard Lonergan (1904–1984) and Max Horkheimer (1896–1973) on the topic of social decline, focusing on the relationship between what Lonergan called “conceptualism” and what Horkheier called “instrumental reason.” I will argue that conceptualism and instrumental reason are distinct conscious intentional phenomena that collude in generating social decline. For the sake of convenience and clarity, I will categorize (with some qualifications) this collusive relationship between conceptualism and instrumental reason as one of “elective affinity.” I will advance my argument, first, by articulating Lonergan’s critique of conceptualism in his Verbum articles. Next, I will turn to Horkheimer’s account and critique of instrumental reason. We will see a striking example of the convergence of conceptualism and instrumental reason in Louis Billot, SJ (1846–1931), a neo-Scholastic theologian and cardinal mentioned specifically by Lonergan and generically by Horkheimer. I will then locate conceptualism and instrumental reason within Lonergan’s theory of intentionality analysis, specifically the levels of consciousness, and will elaborate on their elective affinity. Finally, within the parameters of Lonergan’s account of social decline, I will outline how their collusion generates social decline.