So, you might think, the absence of behavior X would really be evidence against sentience, while its presence alone in a creature might not be relevant to determining sentience.
I might be wrong about this or might be misunderstanding you, but I believe that, in any case where the absence of X is evidence against Y, the presence of X has to be evidence for Y. (Equivalently, whenever the presence of X is evidence for Y, the absence of X has to be evidence against Y.)
This does go against the common statement that āAbsence of evidence is not evidence of absence.ā But we can understand that statement as having a very large kernel of truth, in that it is often the case that absence of evidence is only extremely weak evidence of absence. It depends on how likely it would be that weād see the evidence if the hypothesis was true.
For an extreme example, letās say that an entity not being made of molecules would count as very strong evidence against that entity being sentient. But we also expect a huge number of other entities to be made of molecules without being sentient, and thus the fact that a given entity is made of molecules is extraordinarily weak evidenceāarguably negligible for many purposesāthat the entity issentient. But itās still some evidence. If we were trying to bet on whether entity A (made of molecules) or entity B (may or may not be molecules; might be just a single atom or quark or whatever) is more likely to be sentient, we have reason to go with entity A.
This seems to sort-of mirror the possibility you describe (though here weāre not talking behaviours), because being made of molecules is a necessary precondition for a huge number of what weād take to be āindicators of sentienceā, but by itself is far from enough. Which does mean evidence of X is extremely weak evidence of sentience, but itās still some evidence, relative to a state in which we donāt know whether X is true or not.
(Iām aware this is a bit of a tangent, and one thatās coming fairly late. The post as a whole was very interesting, by the wayāthanks to everyone who contributed to it.)
I might be wrong about this or might be misunderstanding you, but I believe that, in any case where the absence of X is evidence against Y, the presence of X has to be evidence for Y. (Equivalently, whenever the presence of X is evidence for Y, the absence of X has to be evidence against Y.)
This does go against the common statement that āAbsence of evidence is not evidence of absence.ā But we can understand that statement as having a very large kernel of truth, in that it is often the case that absence of evidence is only extremely weak evidence of absence. It depends on how likely it would be that weād see the evidence if the hypothesis was true.
For an extreme example, letās say that an entity not being made of molecules would count as very strong evidence against that entity being sentient. But we also expect a huge number of other entities to be made of molecules without being sentient, and thus the fact that a given entity is made of molecules is extraordinarily weak evidenceāarguably negligible for many purposesāthat the entity is sentient. But itās still some evidence. If we were trying to bet on whether entity A (made of molecules) or entity B (may or may not be molecules; might be just a single atom or quark or whatever) is more likely to be sentient, we have reason to go with entity A.
This seems to sort-of mirror the possibility you describe (though here weāre not talking behaviours), because being made of molecules is a necessary precondition for a huge number of what weād take to be āindicators of sentienceā, but by itself is far from enough. Which does mean evidence of X is extremely weak evidence of sentience, but itās still some evidence, relative to a state in which we donāt know whether X is true or not.
(Iām aware this is a bit of a tangent, and one thatās coming fairly late. The post as a whole was very interesting, by the wayāthanks to everyone who contributed to it.)