In this chapter, spacetime is identified as the empirical realm, to be understood in a relational sense. The spacetime construct emerges from the quantum substratum by way of actualized transactions, which establish spacetime events and their structural connections. This process is discussed in terms of causal set theory. The quantum substratum constitutes the reference for “absolute motion,” and rest-mass systems in the substratum define inertial frames. The transactional process breaks time symmetry, thus establishing an arrow of time and shedding light on the Second Law of Thermodynamics. Implications for free will are also discussed.