The causal set -- mathematically a finitary partial order -- is a candidate discrete substratum for spacetime. I will introduce this idea and describe some aspects of causal set kinematics, dynamics, and phenomenology, including, as time permits, a notion of fractal dimension, a (classical) dynamics of stochastic growth, and an idea for explaining some of the puzzling large numbers of cosmology. I will also mention some general insights that have emerged from the study of causal sets, the most recent one concerning the role of intermediate length-scales in discrete spacetime theories.
Symmetry breaking and symmetry of physical laws; Quantum mechanics and emergence; Emergence, laws and unexplained features of nature; Relational quantities.
Debate among all discussants. Individual statements and questions about Roberto Unger's theses; Time in cosmology and the notion of time in mathematics stand out as main topics;