A central argument of Dialectic of Enlightenment is that modern reason, by narrowing its function to that of a mere instrument for calculation and control, becomes a primary agent of domination. This “instrumental reason” is defined by its effectiveness in achieving the ends of self-preservation rather than its capacity for reflection or its pursuit of truth. The authors trace how this logic of subjugation is first applied to external nature, but inevitably rebounds upon humanity itself. Consequently, social relationships become systems of coercion and the autonomous subject dissolves. In this analysis, the advance of technical rationality is a process in which thought becomes a tool that perfects its own enslavement.

The book traces this development to Enlightenment thinkers like Francis Bacon, for whom knowledge is synonymous with power. The goal of science is not “satisfaction, which men call truth,” but “‘operation,’ the effective procedure” (2). This redefinition strips knowledge of any purpose beyond its utility in manipulating the world. Horkheimer and Adorno assert that “technology is the essence of this knowledge,” which “aims to produce neither concepts nor images, nor the joy of understanding, but method, exploitation of the labor of others, capital” (2). Reason becomes a tool for fabricating other tools, serving the bourgeois economy by optimizing production in factories and efficiency on the battlefield. This purely functional approach to knowledge requires disenchanting the world, turning nature from a living entity into mere material to be controlled, classified, and exploited.

Horkheimer and Adorno posit that the logic of control, once perfected on external nature, turns inward to organize human society. The same rationalizing impulse that subjugates the natural world produces social hierarchies and systems of compulsion. The book argues that “the generality of the ideas developed by discursive logic, power in the sphere of the concept, is built on the foundation of power in reality” (9). Social oppression thus takes on the appearance of rational necessity, as the domination of the many by the few is framed as the efficient organization of the whole. The allegory of Odysseus and the Sirens illustrates this dialectic: to survive the Sirens’ deadly song, Odysseus has his sailors, the workers, plug their ears with wax and row onward, while he, the master, has himself bound to the mast. These tactics prefigure a modern society where reason enforces and perpetuates an order of domination. The workers are cut off from experience to ensure their productivity, while the master can experience art only as a powerless observer. Both are diminished by their social roles as domination defines their identities. 

The authors argue that, ultimately, the relentless application of instrumental reason corrodes the thinking subject itself. As the world is progressively transformed into an administered object, the individual, too, becomes a calculable and controllable entity. The subject’s inner life is hollowed out until nothing remains but the abstract function of perception and systematization. As the text states, domination over nature “turns against the thinking subject itself; nothing is left of it except that ever-unchanging ‘I think,’ which must accompany all my conceptions” (20). Reduced to a mere cog in a self-produced machine of thought, the individual loses all autonomy, resorting to expected behaviors and conventional reactions. The triumph of instrumental reason therefore has a tragic trajectory. In the quest for total mastery, the subject effectively engineers their own dissolution.