I don't think there's a useful question here, for a few reasons.
One is that it builds in the assumption that sentience or consciousness - the existence of 'subjective experience' - is on some sort of linear scale. We don't have any evidence that it is. There probably are differences in various qualities of subjective experience, and probably even detail and information content, but to what extent can we say that subjective experience exists more for one conscious entity than for another?
Another is that we also have no idea whether anencephalic babies have subjective experience, and can't know. We can observe from the outside that they don't appear to respond to a lot of stimuli that more ordinary humans do respond to, and much neural activity ordinarily associated with such stimuli are absent even in the parts of the nervous system that remains in such cases. That doesn't really tell us anything about whether there exists a subjective experience of being anencephalic.
So the question really asks three questions, two of which we can't know the answer by definition and then asks us to compare those on some undefined and possibly nonexistent scale.
I suppose it might serve some anthropological purpose in evaluating how people interpret such ill-defined questions, but not much more.
So the question really asks three questions, two of which we can't know the answer by definition and then asks us to compare those on some undefined and possibly nonexistent scale.
All questions ever asked on LW presupposes something, usually multiple somethings, and sometimes too many somethings to feasibly enumerate.
Yet people still have productive discussions nonetheless. I think this is also possible here.
The main presumption that some aspect of cognition is measurable and comparable across different formations of mass-energy-information certainly doesn't seem too far-fetched.
I'm curious to see what the views of various community members are in regards to those attributes we typically ascribe to humans when put in comparison to the edge case where it's clearly absent, i.e. babies born without a brain (Anencephaly)
See: https://en.wikipedia.org/wiki/Anencephaly
I personally am not well informed enough about their inner workings to have decided.
The reason for comparing to the edge case is because it's a very low bar to clear, so even minute differences should be more easily discernable.