Time-Bound Organism: Temporality in Biological and Cognitive Systems

Existential Realism (ER) is an ontological framework distinguishing existence, confined to the present moment, from reality, which spans past and future entities by virtue of their causal or informational connections to the present. This paper extends ER’s metaphysical insights into the biological and cognitive domains, arguing that living systems—from humans to bacteria—are fundamentally time-bound organisms whose behavior and identity are shaped by temporal structures. Advanced organisms like humans exhibit memory, anticipation, predictive coding, narrative identity formation, mental time travel, temporal binding of events, and decision-making based on past experiences and future possibilities. At the same time, simpler organisms (plants, bacteria, slime molds) demonstrate tropisms, endogenous clocks and rhythms, and responses to temporally structured environments (e.g. day/night cycles, seasonal changes, intermittent stimuli) that function as primitive “models” of time. In all cases, past events that no longer exist continue to influence present behavior through physical traces or learned information, while future events that do not yet exist are nevertheless anticipated and built into current plans and physiological states. These empirically grounded temporal behaviors support ER’s claim that past and future entities are real (via causal effects, structural traces, or inferential links) despite their lack of present existence. By surveying examples from neuroscience (memory engrams, Hebbian plasticity, circadian timing in the brain) and biology (plant stress memory, microbial anticipatory foraging, slime mold learning), we show that temporally extended behavior in organisms depends on internal representations of time. This aligns with ER’s two-tiered ontology: organisms exist only in the present, yet they operate within a wider temporal reality. We conclude with reflections on how ER’s perspective illuminates life as a temporally structured phenomenon, and how an organism’s identity and responsiveness are sculpted by the interplay of past realities and future possibilities.