You may see this as a nitpick, but I don’t think it is. Please note also that I’m not trying to start a semantic argument, but to clarify a point – more on that in a moment.
The word George Kaplin used was cogitate. While the dictionary definition means “to think deeply and/or carefully; ponder”, I’d hazard a guess that when used in this context, it’s used more like “possessing cognitive ability”, which is much more general and bears a lower standard than “intellectual ability”. Taken in this way, there’s a rather marked effect on your points:
Because the ability to solve differential equations is not a characteristic of cognition; granted, if one posits that cognition is necessary but not sufficient for abstract thought (e.g., mathematical problem solving), it may be taken as proof of cognitive ability – but lack of mathematical prowess does not indicate lack of cognition. One would hope to use a lowest common denominator as the defining bar for cognition, whatever it may be.
This is an interesting (and contentious) question (I hope I don’t misrepresent any of the following). On the one hand, you have people like Peter Singer who make that exact point, then conclude that, from an ethical point of view, animals deserve to be treated in the same way humans are. On the other hand, people like Daniel Dennett want to claim that there is something that separates humans from animals, which can be attributed to the cognitive architecture humans have. Perhaps you’d be interested in this piece by Aaron Sloman, which delves into ontological questions from an artificial intelligence standpoint (it’s not quite on target for this discussion, but interesting nonetheless).
To get back to a prior point as promised, your statement above was In terms of deciding personhood I place no importance whatsoever on “sentience” or whatever intellectual ability you care to name. I most likely missed it, but I’d like to ask for clarification – just what is your standard for deciding personhood?
Intellectual ability may not be constant but, using the distinction from above, one might say that’s the wrong measure. Rather, perhaps we should use cognitive capability instead. If so, then a person’s stance on the Terry Schiavo case would be a good indicator as to where to draw the line.
Arguing potentiality always seemed kind of silly to me, as it raises the “what about a single sperm” or “what about a thumb” questions. Relying on “encoded in genetic material” to buttress the argument is even sillier, as it just makes the absurdity of “a single skin cell is not only alive, but human” more pronounced. What must be part of the argument is actuality – which separates fetal development from the passed-out drunk.
Again, I don’t think “intellectual ability” is an appropriate term to inject into this argument, and I don’t think you’ll find anyone advocating for it.
You’re last sentence is right, so long as you’re using the term “intellectual ability”. Out of curiosity, what is your position on the Terry Schiavo case?
