The Singular Universe and the Reality of Time: A Proposal in Natural Philosophy is a book about cosmology, philosophy of time, metaphysics and scientific naturalism by the American theoretical physicist Lee Smolin and the Brazilian philosopher Roberto Mangabeira Unger. The authors argue that the current crisis in cosmology is a result of physicists making the wrong commitments to universalizing local experiments and to a block universe. They suggest instead that new research projects would be revealed if we took seriously the idea of one, and only one, universe as well as the reality of our experience of time. This new paradigm, they say, would also give rise to the revolutionary notion that the laws of nature might not be immutable. The book was initially published by Cambridge University Press on December 8, 2014.

Roberto Mangabeira Unger is a Brazilian philosopher, jurist and politician. His work is in the tradition of classical social theory and pragmatism, and is developed across many fields including legal theory, philosophy and religion, social and political theory, progressive alternatives, and economics. In natural philosophy he is known for The Singular Universe and the Reality of Time. In social theory he is known for Politics: A Work in Constructive Social Theory. In legal theory he was associated with the Critical Legal Studies movement, which helped disrupt the methodological consensus in American law schools. His political activity helped the transition to democracy in Brazil in the aftermath of the military regime, and culminated with his appointment as Brazil's Minister of Strategic Affairs in 2007 and again in 2015. His work is seen to offer a vision of humanity and a program to empower individuals and change institutions.