Offering a contemporary perspective on the theory of modernity that differentiates it from its predecessors, this reconstruction has been expanded to include a fourth instrumental aspect. In addition to the recognition of the three parts of traditional modernity—freedom, equality, and solidarity—that follow the basic ideas of the constitutional revolutions of the 18th century, this updated vision introduces responsibility. Concerning itself with what the sociology of development, risk, and ecological crisis have added to these classical ideas, the addition of the fourth part, responsibility, seeks to recognize the experiences of successive eras, and the 20th century in particular.