Who or what is conscious? Because subjective experience is directly accessible only to the first‑person self, judgments about consciousness in other entities must rely partly on analogy. Historically such analogies have focused on non‑human animals, but rapid advances in artificial intelligence have raised the question of whether machines could be conscious. To address this we propose a causal framework for evaluating evidential analogies.\ \ The framework distinguishes two kinds of similarity: similarity in the factors plausibly involved in generating consciousness, and similarity in downstream behavioural or cognitive effects. We weight source‑target similarity by its causal relevance, while allowing for unknown causes, disabling differences, and alternative routes to consciousness.\ \ When applied to biological systems the framework explains why analogical support generally weakens as the causal distance from humans increases. Applied to contemporary AI, it suggests that behavioural similarity alone offers limited evidence for consciousness because the relevant causal correspondences remain poorly established. The framework also clarifies what kind of evidence—directly linking AI mechanisms to known consciousness‑generating factors—would strengthen claims of artificial consciousness.\ \ Review