Theories or ideas, no matter how lofty, are not immune from historical circumstance: the latter often discloses what otherwise is left unsaid. Far from being an assortment of random data, history from this angle remains a great taskmaster—by teaching us about the complex ambivalences and unintended consequences of rational designs. The ideas of “modernity” and “enlightenment” are a prominent case in point. No one can doubt the loftiness and even intrinsic nobility of these labels. Basically, modernity (as understood in the West) was meant to inaugurate a new age of human freedom and self-determination, as contrasted with previous eras marked by political, clerical, and intellectual tutelage. In turn, enlightenment—in Kant’s memorable phrase—was meant to awaken humankind from the “slumber of self-induced immaturity” and ignorance, thereby paving the way for the undiluted reign of scientific knowledge and moral self-legislation. As history teachers, these and related ideas did indeed generate some of the desired results—but often in unforeseen ways and straddled with dubious or less noble implications. Like a deep shadow, these implications accompanied from the beginning the modern spreading of “light.” At the very onset of the new age, Francis Bacon proclaimed the equation of knowledge with power—thereby vindicating the prospect of human mastery over nature (as well as over less knowledgeable people). In the domain of politics and ethics, the modern maxim of freedom exacerbated a formula which Aristotle already had used against non-Greeks: “meet it is that barbarous peoples should be governed by the Greeks.”1 The merits and demerits of modernity have been widely discussed in recent decades from a variety of angles (anti-modern, modernist, postmodern)—but often in a purely academic vein. Here again, historical circumstance demands its due. It was during the past (twentieth) century that some of most disturbing and hideous connotations of the modern project of unlimited mastery came out into the open, and it was in response to these implications—manifest in fascism and Stalinist communism—that some of the most penetrating analyses of this project were formulated. In view of the hundredth anniversary of Theodor Adorno’s birth (1903), it is fitting that close attention should be given again to his critical work—particularly to the magisterial Dialectic of Enlightenment (written in collaboration with Max Horkheimer) and the magnum opus of his later years, Negative Dialectics. Roughly in the same historical context, another leading German thinker—Martin Heidegger—launched an equally devastating attack on the totalizing machinations of modern technology and modern politics (in writings which only recently have became available). The following pages start out by reviewing the arguments of these two thinkers, with an emphasis on both their similarities and their differences. With the demise of fascism and Stalinist communism, these arguments seem to have lost their contextual force; this, however, is far from being the case. Under the aegis of globalization, the totalizing ambitions of Western modernity are revealed today on a planetary scale: in the opposition between the hegemonic “North” and the dominated “South.” Speaking no longer from the European “center” of modernity but from the nonWestern periphery—and drawing freely on the insights of Adorno and Heidegger—the Latin America Enrique Dussel has formulated a new critique of the modern project, a critique which— without denying its liberating potential—takes aim at the prospect of global mastery as the “underside of modernity.”