Where Does the Will To Live Come From… in Humans and Nonhumans Alike?

The English word "agency" traces back to the Latin "agere," meaning "to do" or "to drive," with origins in the Proto-Indo-European root *ag-, signifying "to lead or move." In the 1600s, the concept of agency evolved beyond its initial passive effect to active incitement. In the realm of living beings, the purposeful actions prompt questions about the ability to influence or direct actions, both of oneself and others.

This stems from humans' heightened sensitivity to authority and influence. The notion of agency also reflects our quest for a distinct force or external driver beyond the physical body itself. Many living organisms possess innate abilities to detect agency, even if they sometimes misinterpret it. Aristotle pondered the existence of an ultimate cause beyond psyche, especially in the unceasing motion of celestial bodies, attributing it to the "Unmoved Mover."

While some interpreted this entity as Aristotle's god—an ultimate agent—his use of the term "theos" hints at its role as the source of energeia, the principle of motion and change that drives all potential forms in the universe. This concept resonates with modern physics' search for a unifying field or constant behind all forces.

Aristotle's term resurfaced in science as "energy," though with a quantitative meaning distinct from Aristotle's metaphysical interpretation. The debate over the agency of organisms has persisted for centuries, questioning who generates goals and where meaning resides. When considering the agency of organisms, one must delve into complex territory.

Researchers studying "agent detection" have identified specific brain regions and processes, such as the ventral temporal cortex and action observation network, that become active when animals identify the source of an action. However, animals show a particular interest in actions that are synonymous with biological life, seeking to distinguish between lifelike and non-living forces.

Life forms prioritize recognizing agents that are synonymous with biological life, separating those forces of change that are alive from those that are non-living. If an animal can discern that the lifelike object isn't another animal, its interest wanes. This distinction is crucial, as living agents are less predictable than external forces like a waterfall, encompassing a broader range of possible choices driven by purpose.

For instance, an antelope's unpredictable behavior stems from its inherent goal-driven nature, constantly reassessing the situation and adjusting actions accordingly. Antelopes, for example, are wary of potential threats and assess whether an entity is alive, seeking to understand the motivations and limitations of another being.

This ability to discern agency and intentions is vital for animals, particularly those that hunt or are hunted, as it enables them to anticipate actions and adapt to the evolving situation.