Materialism › Phylogenetic
Birch’s Comparative Sentience: Consciousness Profiles Across Diverse Minds
Sentience Mapped Across Species Under Uncertainty
Birch offers a method for studying consciousness across animals and AI without first settling what consciousness is. He rests inquiry on one minimal ‘theory-light’ hypothesis (conscious perception enables a cluster of flexible abilities that unconscious perception does not), replaces ‘more or less conscious’ with profiles across five dimensions, and prescribes proportionate precaution for any ‘sentience candidate’.
Jonathan Birch
What consciousness is
Birch defines sentience broadly as the capacity for phenomenal consciousness and narrowly as the capacity for valenced experience, states that feel good or bad to their subject. He does not identify consciousness with any particular physical or functional property.
Mind and body
Left open on purpose. Birch treats materialism, dualism, panpsychism, and their variants as lying within a zone of reasonable disagreement and builds his framework to work across all of them.
Mechanism
A minimal ‘facilitation hypothesis’ holding that phenomenally conscious perception of a stimulus boosts, relative to unconscious perception, a cluster of abilities directed at that stimulus. The link is evidential, which lets researchers infer consciousness from behaviour without choosing a theory.
Core claims
- Asking whether one animal is more conscious than another is generally malformed, because consciousness varies along independent dimensions.
- Theory-heavy approaches inherit their chosen theory's flaws, and theory-neutral approaches cannot say what the data are evidence for, so a theory-light middle path is needed.
- Birch's 2021 team review of more than 300 studies led cephalopod molluscs and decapod crustaceans to be covered by the UK Animal Welfare (Sentience) Act 2022.
- Large language models trained on human descriptions of experience can reproduce behavioural markers of sentience, so those markers lose evidential force for AI (the gaming problem).
Criticisms
The facilitation hypothesis ties phenomenality to cognitive access, which theorists who follow Block's access-phenomenal distinction reject; Birch replies that the tie is evidential, not constitutive. The five dimensions are stipulated rather than derived, and their independence is asserted rather than shown.
Implications
- AI consciousness: Possible
- Birch counts non-biological systems as possible sentience candidates warranting precaution, while warning that behavioural evidence from language models is unreliable.
- Meaning and purpose: Humanistic only
- Birch's concern is ethical and practical, protecting any being that may be able to suffer, with no claim about cosmic purpose.
Related theories
- Ginsburg and Jablonka's Associative Learning During Evolution (Overlap)
- Bayne’s Unified, Multidimensional Consciousness: Structure Before Mechanism (Overlap)
- Block's Biological Reductionism (Contrast)
- Andrews's Consciousness Without Complex Brains (Compatible)
Sources
- The Edge of Sentience: Risk and Precaution in Humans, Other Animals, and AI, Jonathan Birch (2024)
- The Search for Invertebrate Consciousness, Jonathan Birch (2022)
- Dimensions of Animal Consciousness, Jonathan Birch, A. K. Schnell and N. S. Clayton (2020)
- Review of the Evidence of Sentience in Cephalopod Molluscs and Decapod Crustaceans, Jonathan Birch, C. Burn, A. Schnell, H. Browning and A. Crump (2021)
- The Learning-Consciousness Connection, Jonathan Birch, S. Ginsburg and E. Jablonka (2021)
- On a Confusion About a Function of Consciousness, Ned Block (1995)