Determined: A Science of Life without Free Will

Determinism is the idea that every phenomenon in the universe, down to the location of a subatomic particle, is caused by preceding factors. Determinism incorporates the nature of change, the unpredictability of chaoticism, and the impacts of meta-cognition—or thinking about thinking.

An electroencephalogram (EEG) is a scan that uses electricity to measure brain activity. The process involves attaching electrodes to the skull or inserting them into the brain using probes to measure activity.

Readiness potential is a term referring to patterns recorded on EEGs corresponding to a person’s preparation to move. Readiness potential originates in the supplementary motor area, a portion of the nervous system that deals with motor function.

The prefrontal cortex is an area of the frontal cortex, the front lobe of the brain. The prefrontal cortex is associated with high-level thinking and decision-making, including making morally “right” choices over easier options. The PFC is further divided into subregions including the dorsolateral PFC (dlPFC), which deals in rational thought, and the ventromedial PFC (vmPFC), which processes emotions. These two areas work together to balance reason and emotion.

These terms are used in relation to free will and determinism. Compatibilists are individuals who believe free will and determinism can coexist, while incompatibilists, like Sapolsky, believe they cannot.

Neuroplasticity refers to the capability of the nervous system to change in response to stimuli. The nervous system can change either by forming new neural connections or by eradicating existing connections. Neuroplasticity accounts for brain changes that may be erroneously attributed to free will.

The amygdala is a structure in the brain that processes anxiety, fear, and aggression. The sensitivity of the amygdala influences behavior, serving as another facet in the case against free will.

Epigenetic changes are alterations to gene expressions that occur because of environmental and behavioral stimuli. Some genes respond to such stimuli by activating or deactivating. Epigenetic changes can be passed down through multiple generations.

Reductionism is the idea that complex processes, systems, or concepts can be broken into component parts and studied to better understand the whole, such as in dissembling a watch to learn how its gears function. While reductionism is a beneficial approach to some complex issues, Sapolsky argues that it is not relevant to the study of behavior.

Chaoticism, also known as chaos theory, is the concept that seemingly random systems are deterministic but in such a way that leaves future outcomes unpredictable. Each step in the pattern is determined by preceding steps, and the level of complexity results in unpredictable outcomes. Human behavior is analyzed through chaoticism to help dispel the concept of free will.

Convergence occurs when two unrelated elements follow similar trajectories. It is seen in evolution when two separate species evolve similar adaptations, such as how birds, bats, and insects can fly but have separate evolutionary paths.

Emergent complexity is a deterministic and sometimes unpredictable process that involves simple elements following simple rules to form complex units. Common examples include ant and bee colonies using swarm intelligence to optimize resource gathering.

Bifurcation occurs when something grows for a time following certain rules and then branches out, with subsequent branches following the same rules before branching. The rules are based on growing to a certain ratio, which accounts for the declining sizes of the new branches. Bifurcation is seen in the ways trees branch, as well as in the formation of capillaries and in the growth of neuronal dendrites.

Quantum indeterminacy is the concept that at the atomic and subatomic levels, indeterminacy, or randomness, occurs. Three branches of quantum indeterminacy are introduced as relevant to the text: wave-particle duality, entanglement and nonlocality, and quantum tunneling.

Wave-particle duality shows that matter can appear as both a wave and a particle. If an electron is not being measured as it is fired at a wall with two slits, it will behave as a wave and pass through both. The concept of a particle being in multiple places at once is called superposition. If the electron is measured, it “knows” and behaves like a particle, passing through one slit, and the slit it will pass through is unpredictable.

Entanglement is a type of bond that can occur between subatomic particles, such as electrons. When entanglement occurs, the two entangled particles affect and complement each other. For example, if one spins to the right, the other will instantly spin to the left. This bond exists over vast distances and can exhibit nonlocality, in which the two particles impact each other instantaneously, meaning their bond is unimpeded by the speed of light—the current known speed limit in the universe.