The free will–determinism discussion is centuries old, with numerous stances taken by philosophers and scientists alike. The debate has clear implications for interpreting causal relations in scientific systems and predicting and influencing the behavior of living organisms, particularly humans. Advances in quantum physics and neuroscience have recently revitalized the debate over free will versus determinism, as depicted in recent books by Robert Sapolsky and Kevin Mitchell. In this article we review and critique Determined: A Science of Life Without Free Will (Sapolsky, 2023) and Free Agents: How Evolution Gave Us Free Will (Mitchell, 2023), which differ in their conclusions regarding how contemporary research findings in genetics, neuroscience, and quantum mechanics support or countervail the notion that people possess free will. Drawing on Killeen et al. (2024) recent analysis of agency, we attempt to reconcile the authors’ perspectives on the premise that the laws of physics, including quantum mechanics, imply hard determinism in terms of past events but can offer only broad, global predictions about a person’s future behavioral outcomes, because people entertain a range of considerations while deciding between available response options.. We suggest probabilistic determinism as a conceptualization of agency that accommodates this past–future distinction in determinism. We invite readers to consider that although behavior is determined, people nonetheless have opportunities to make choices and exercise autonomy.
