Background: The philosophical contributions of Jean-Paul Sartre and Albert Camus represent a critical nexus in 20th-century existentialism. While often grouped together, their views on the fundamental nature of human existence diverged significantly, creating a rich and enduring debate that continues to inform contemporary thought.

Objective: This article provides a detailed comparative analysis of the concepts of human nature in the philosophies of Sartre and Camus. The study aims to move beyond common generalizations to meticulously dissect their foundational differences regarding freedom, consciousness, ethics, and revolt.

Methods: The study employs a comparative textual analysis of key philosophical and literary works by both authors. The analytical framework is structured around three core thematic pillars: (1) the ontological starting point of human existence (Sartre's "nothingness" vs. Camus's "the absurd"); (2) the characteristic human response (Sartre's "radical freedom" vs. Camus's "revolt"); and (3) the resulting ethical frameworks (Sartre's "authenticity" vs. Camus's "limits" and "solidarity"). The analysis is supported by relevant secondary scholarship [e.g., 1, 2, 3, 5, 11, 12].

Results: The analysis demonstrates that Sartre posits a human nature defined by "existence preceding essence," which condemns individuals to a radical and unbound freedom to create their own meaning and values. This freedom is accompanied by the peril of "bad faith." In stark contrast, Camus argues that the universal experience of the absurd gives rise to revolt, an act that reveals an inherent and shared human nature. This revolt establishes intrinsic moral limits, best summarized by his axiom, "I rebel, therefore we are."

Conclusion: While both Sartre and Camus champion human dignity in a meaningless universe, they offer profoundly different paths. Sartre’s humanism is rooted in absolute individual responsibility and self-creation, while Camus’s is a humanism of moderation, shared dignity, and solidarity born from a common condition. This fundamental distinction holds critical implications for contemporary ethical and political discourse.