Darwinian evolutionary theory has achieved unparalleled success in explaining biological variation, adaptation, and diversification across time. In contemporary discourse, however, its explanatory reach is often extended beyond biological change to adjudicate questions concerning human existence itself. This paper argues that such an extension exceeds the legitimate scope of evolutionary explanation.Rather than disputing the empirical validity of Darwinian mechanisms, the paper offers a meta-logical assessment of what evolutionary theory is equipped to decide. It first clarifies that evolutionary explanation operates within an already constituted biological domain, accounting for transformations and divergences internal to that domain. It then identifies and rejects a widespread but unjustified inference from biological similarity to existential continuity, showing that genetic relatedness and common descent do not entail conclusions about existential kind.The paper further examines the problem of human singularity: despite clear biological continuity with other primates, human existence exhibits a unique configuration of symbolic, cultural, normative, and reflexive capacities not replicated or approximated in any extant non-human species. This singularity is interpreted not as a refutation of evolutionary theory, but as a limit result indicating where evolutionary explanation ceases to be decisive.The central conclusion is that Darwinian theory cannot decide the question of human existence. Recognizing this limit does not weaken evolutionary science; rather, it preserves its conceptual integrity and prevents an illegitimate inflation of explanatory authority. By restoring a principled boundary between biological explanation and existential adjudication, the paper reopens the human question as a genuinely philosophical problem.