How do we approach the question of an alternative develop­ ment (for the Third World no less than for the First) in ways that go beyond mere literary utopias? This essay seeks to ex­ plore this question by examining the kinds of behavior that are revealed as the so-called popular classes of Latin Ameri­ can cities confront their daily struggles of survival and liveli­ hood. It is agued that their behavior reflects an existential Reason that must be balanced off against the cognitive Rea­ son which underlies the Enlightenment model ofmoderniza­ tion. Four aspects of this model are examined: in metaphys­ ics, epistemology, philosophical anthropology, and the legal­ political order. The essay concludes by aguing that existen­ tial and cognitive Reason stand in a dialectical relationship where each defines and sets limits to the other, thus preven­ ting the totalization of any model, including the hegemonic model of capitalist modernization.