Final paper for APPPHYS 363: Modern Physics & Literature. 1. Introduction “I don’t quite understand what it is that compels me to type this letter. Perhaps it is to leave some vague reason for the actions I have recently performed. I don’t really understand myself these days. I am supposed to be an average, reasonable and intelligent young man. However, lately (I can’t recall when it started) I have been a victim of many unusual and irrational thoughts… After my death, I wish that an autopsy would be performed on me to see if there is any visible physical disorder. I have had some tremendous headaches in the past and have consumed two large bottles of Excedrin in the past three months.”¹ Charles Whitman wrote what would effectively become his suicide note the night before he committed the mass murders at the University of Texas tower shooting on August 1, 1966. The excerpt above is from the note. Whitman would kill 14 and wound 31 others the next day before being shot and killed by police. An autopsy showed that Whitman indeed had a tumor in the white matter above his amygdala, a region of the brain associated with emotion regulation and aggression.² Is Whitman an evil person or a victim of biology? If we had a perfect account of what was happening at every synapse in Whitman’s brain, and we learned the difference between what creates a Whitman and not Gandhi, would we consider him unlucky? These are hard questions because they touch on free will, a phrase that has emerged over the past two millennia as the "canonical designator for a significant kind of control over one's actions.”³ In talking about free will, we have to consider questions about causation, laws of nature, time, the relationship of causal and reasons-based explanations, the nature of motivation, and right and wrong. Even if we get past those questions, there remains the purely empirical question of whether we have free will, and to what extent we have it. Something we have done as a species quite well is to use logic, and by extension, math and physics, to get closer to answers to hard questions. Newtonian mechanics helped us understand the motion of celestial bodies. General relativity explained the nature of gravity. These are examples of classical physics. Classical physics operates under the assumption that the universe is a well-ordered, predictable system. This leaves little room for an indeterminate idea like free will. But quantum mechanics introduces inherent randomness and suggests that certain events at the microscopic level are fundamentally unpredictable.⁴ It breaks the strict causal chain of events implied by classical physics. This indeterminism leaves open a space where not all future events are predetermined, allowing for free will to operate independently of deterministic physical laws. As a curious species, this is an interesting pond to swim in. In this paper, I will explain how we should think about free will in the context of physics. The discussion will be grounded in examples of emergence, a phenomenon where higher-level properties arise from the interactions of lower-level components in a system. This paper will start with two examples from the classical world, then focus on free will as an emergent property, and finally discuss the philosophical implications of these findings. All this to make the claim that whether or not one believes in free will depends on how much influence they think quantum mechanics has on the decision-making processes within the brain. 2. Emergence in Thermodynamics Emergence is the phenomenon where larger entities and patterns arise through interactions among smaller entities that themselves do not exhibit such properties. In other words, emergent properties are those that are not present in the individual components but manifest when these components interact at a system level. Both physicists and philosophers have thoughts on emergence. Karen Barad, a physicist, has an idea called agential realism, which states that emergence results through dynamic interactions among parts, where the relationships and exchanges between them create new, higher-level properties. This process is complex and non-linear, involving both material and discursive elements that shape reality and knowledge.⁵ Henri Bergson, a French philosopher, highlights the continuous flow of time and the ongoing creative process that leads to the diverse forms of life we see.⁶ How does this manifest in the real world? One example is thermodynamics. At the fundamental level, thermodynamics is grounded in the behavior of atoms and molecules. But when we observe large collections of these particles, we see emergent properties that are not evident at the microscopic level. Temperature, pressure, and viscosity are examples of such properties. These macroscopic quantities arise from the collective behavior of many particles and can be effectively described without detailed knowledge of each particle's state. The waiter need not know the state of the universe to know what a customer wants to order for dinner; they can just ask. It is important to note that emergent properties in thermodynamics are described deterministically and can be predicted from the deterministic behavior of atoms and molecules, illustrating the concept of weak emergence. To be clear, even though emergent properties may be complex, weakly emergent properties can be predicted or simulated based on the underlying micro-level laws, while strongly emergent properties cannot be predicted or derived from the underlying micro-level laws, no matter how much we know about the microscopic details. The examples listed earlier are weakly emergent properties. Some think that consciousness is a strongly emergent property. More on that later. Regardless, the transition from the microscopic to the macroscopic is a cornerstone of thermodynamics, showing how complex behaviors can emerge from simple, fundamental interactions while still being rooted in the deterministic laws governing the behavior of individual particles. Zooming in, statistical mechanics provides the microscopic foundation for thermodynamics by using statistics to link the behavior of individual particles to the macroscopic properties described by thermodynamic laws. It further proves this concept by providing the bridge between microscopic interactions and macroscopic properties. The distribution of particle velocities in a gas, described by the Maxwell-Boltzmann distribution, leads to the emergent property of temperature.⁷ Pressure arises from the collective impact of countless molecular collisions with the walls of a container. In statistical mechanics, emergence is characterized by the transition from individual particle behavior to collective phenomena that can be described by statistical averages and distributions. This framework allows us to derive macroscopic thermodynamic laws from the underlying microscopic dynamics. The ensemble approach in statistical mechanics treats large numbers of particles as collections, where the exact state of each particle is less important than the overall statistical properties of the system. Emergence in thermodynamics illustrates how higher-level properties and behaviors can arise from the interactions of simpler elements, with statistical mechanics providing the theoretical foundation for understanding this transition. This interplay between the microscopic and macroscopic realms demonstrates the power of emergent properties and highlights the importance of statistical methods in uncovering the principles governing complex systems.⁸ 3. Computing and Weak Emergence Another example is computing. At the fundamental level, computing is based on transistors, logic gates, and binary code. These basic elements interact to give rise to emergent properties like software and artificial intelligence (AI). It can be agreed that there is nothing mysterious about AI, since the underlying components are well understood. As such, here see agential realism in action - emphasizing that the behaviors and capabilities of things like AI emerge from the complex interplay of their underlying components. These properties can be predicted or simulated based on the underlying micro-level laws, demonstrating the principle of weak emergence. The components at the micro-level follow deterministic rules, their interactions lead to the emergence of complex, higher-level functionalities that define modern computing systems. That being said, we can see that the fundamental components and the emergent properties in computing are deterministic. Emergent properties in computing, much like in thermodynamics, arise from simple, deterministic interactions at a fundamental level. 4. Conway’s Game of Life Before we move on to the mind, let’s make a quick pit stop at the Game of Life. Conway's Game of Life provides a compelling illustration of how simple, deterministic rules can give rise to complex, emergent behaviors. In the Game of Life, a cellular automaton evolves based on a set of straightforward rules governing the birth, survival, and death of cells.