Jenann Ismael: The link between time, totality, and determinism

The speaker, Jen, from the University of Arizona, is introduced at a lecture hosted by the Rotman Institute. She discusses her recent book on how physics can make us free and hints at her talk's focus on time, totality, and transcendence. She acknowledges the newness of her material and invites interruptions for a dynamic discussion, setting a collaborative tone for the exploration of determinism, fatalism, and the nature of time as influenced by relativity and Newtonian mechanics.

Jen delves into the transcendent perspective, which views time in a four-dimensional context, including past, present, and future. She challenges the notion that this perspective inherently leads to fatalism, arguing that while it's difficult to reconcile this view with an open future, the transcendent representation doesn't necessarily imply that the future is fixed or predetermined. She emphasizes that such a representation is a way to understand history without implying determinism of future events.

The paragraph explores the philosophical tension between determinism and free will. Determinism, as influenced by Newtonian mechanics, suggests that the laws of nature and initial conditions could, in theory, predict all future events. However, Jen argues that this doesn't account for the complexities of causality and the intrinsic nature of events in space-time. She points out that determinism, in its simplest form, doesn't necessarily negate free will, as it doesn't consider the 'on-the-ground' causal order that influences our actions.

Jen discusses the concept of a 'causal patch' in the context of Minkowski space-time, which is the set of events that can influence or be influenced by an event. She explains that even in deterministic Newtonian and Minkowski space-times, the causal past does not logically determine future events. This is due to the presence of 'space invaders,' or influences outside one's past light cone that can affect the future. This suggests an open future where determinism does not fix all outcomes.

The speaker examines the relationship between causality and the structure of space-time, particularly in the context of general relativity. She notes that the local structure of space-time is still deterministic, meaning that events at a specific location are influenced by their immediate surroundings. However, the global structure, especially when considering the universe's totality, can exhibit different behaviors, challenging the idea that determinism is absolute.

Jen further explores determinism, distinguishing between local microscopic laws that govern immediate interactions and global deterministic laws that describe the universe's total evolution. She argues that while global laws can be represented deterministically, they do not constrain the local causal order, leaving room for free will. The local causal structure is open and not predetermined by the global state of the universe.

The lecture touches on the discomfort some feel regarding determinism and its implications for human agency. Despite the deterministic description of the universe's evolution, our actions and decisions are integral to the unfolding of history. Jen suggests that the deterministic view does not physically necessitate a single future but rather describes a structure that is made explicit through a developmental process, which includes our conscious decisions.

Jen introduces the concept of dual descriptions to reconcile the transcendent and imminent perspectives of the universe. The transcendent perspective provides a holistic view, while the imminent perspective is experienced through our situated actions in history. She argues that these perspectives are complementary, offering different but compatible ways to understand the universe and our role within it.

The speaker discusses the relationship between global deterministic laws and local causality. She emphasizes that while global laws describe the universe's total state, they do not dictate the local interactions that constitute our reality. These local interactions, governed by what she calls 'on-the-ground' causal order, are where our actions and decisions make a difference.

Jen concludes by addressing the idea that the universe's initial conditions and laws might predetermine our actions. She argues that while the universe's history can be described by deterministic equations, the future remains open and is not fixed by the past. Our decisions and actions contribute to the unfolding of history, reflecting an openness that is compatible with both determinism and free will.