Hey Max, good question. I think we need to clearly separate our metaphysics from our epistemology in this area. If an entity is sentient if and only if there is something it is like to be that entity, then it’s hard to see how sentience could come in degrees. (There are closely related phenomena that might come in degrees—like the intensity of experience or the grain of sensory input—but those phenomena are distinct from sentience.) There are certainly going to be cases where it’s difficult to know if an entity is sentient, but our uncertainty doesn’t imply that the entity is only partially sentient. I think it’s plausible that this area of epistemic indeterminacy could remain quite large even with all the empirical facts in hand.
However, there are some theories of mind on which it looks like there could be cases of metaphysical indeterminacy. If a certain type of reductive physicalism is true, and sentience doesn’t reduce to any one feature of the brain but is instead a cluster concept, and the features that constitute the concept aren’t coextensive, then there could be cases in which we don’t know if an entity is sentient even with all the empirical and the philosophical facts in hand. (Technically, the fact that it can be metaphysically indeterminate that an entity possesses a property doesn’t entail that the property comes in degrees, but it’s a natural extension.)
Hey Max, good question. I think we need to clearly separate our metaphysics from our epistemology in this area. If an entity is sentient if and only if there is something it is like to be that entity, then it’s hard to see how sentience could come in degrees. (There are closely related phenomena that might come in degrees—like the intensity of experience or the grain of sensory input—but those phenomena are distinct from sentience.) There are certainly going to be cases where it’s difficult to know if an entity is sentient, but our uncertainty doesn’t imply that the entity is only partially sentient. I think it’s plausible that this area of epistemic indeterminacy could remain quite large even with all the empirical facts in hand.
However, there are some theories of mind on which it looks like there could be cases of metaphysical indeterminacy. If a certain type of reductive physicalism is true, and sentience doesn’t reduce to any one feature of the brain but is instead a cluster concept, and the features that constitute the concept aren’t coextensive, then there could be cases in which we don’t know if an entity is sentient even with all the empirical and the philosophical facts in hand. (Technically, the fact that it can be metaphysically indeterminate that an entity possesses a property doesn’t entail that the property comes in degrees, but it’s a natural extension.)