sentience

Sentience is the capacity to have subjective experiences, such as sensations, feelings, and emotions. It is often framed as a first-person perspective on experience, distinguishing what is felt from mere information processing or behavioral output. In many philosophical and ethical contexts, sentience is treated as the minimum requirement for moral consideration, because it underpins the capacity to suffer or enjoy.

Sentience is related to, but not identical with, consciousness, awareness, or intelligence. Some accounts equate sentience with phenomenal experience, while others reserve the term for the ability to feel pain, pleasure, or affective states. The scope of sentience is disputed, especially regarding non-human animals and hypothetical artificial systems. Most scientists acknowledge that many vertebrates show indicia of affective states; evidence for certain invertebrates and other non-traditional beings is debated and evolving.

Because subjective experience cannot be measured directly, researchers rely on indirect indicators. Behavioral responses to potentially aversive stimuli, the analgesic modulation of responses, learning about avoidance, and neural and physiological correlates are used to infer affective states. These methods aim to distinguish genuine experiences with valence from simple reflexes or automatic reactions.

Ethical and policy discussions treat sentience as central to animal welfare, wildlife protection, and debates on future machine intelligence. The term is contested in philosophy, with questions about the minimum conditions for a being to be sentient and what kinds of experiences matter for moral status.