An Analysis of the Essence of Being Human in The Substance through Thomas Aquinas’s Philosophy

Abstract

Thomas Aquinas, a philosopher of the natural law tradition, describes human beings as “rational animals.” According to Aquinas, once created by God, the capacity for reason constitutes the defining characteristic of living beings. When this perspective is applied to the film The Substance, one of the protagonists, Su, presents a complex case of humanity: Su’s origins are neither those of a naturally born human nor of a straightforward clone, nor was Su intended to coexist temporally with the film’s other characters. Moreover, Su ultimately transcends a mere extension of another human being, thereby opening up intriguing questions in legal philosophy.

As the narrative unfolds, Su exhibits not only “reason” but also “free will” and a “conscience” — qualities that Aquinas identifies as the very essence of humanity. Conversely, under the Civil and Commercial Code (Section 15), personality begins with the full completion of birth as a living child and ends with death. A child en ventre sa mere is capable of rights, provided that the child is thereafter born alive — a definition that plainly excludes Su’s existence. This discrepancy highlights a conflict between positive human law and the higher-order mandates of divine and natural law.