Consciousness, at its most basic, is the act of cognition engaging with sensory input. When an organism can take in information and process it, consciousness is present. Self-awareness, reflection, emotion, and identity are later developments—important, but not required for consciousness itself. Consciousness is the state of being aware—of the world, of oneself, and of experience itself. Across history, it has been described as soul, mind, spirit, or brain process. While explanations evolve with knowledge, the core phenomenon remains: subjective experience arising within a thinking organism.