Jay says, “If you add one hundred zeroes together, your sum will still be zero. In the same way if sentience, brain waves, and conscious desires by themselves do not have any bearing on personhood, putting them together does not help.”
It’s true that a hundred zeroes still sum to zero. But what about a hundred ones?
It strikes me that what may be going on here resembles what philosophers call the “sorites paradox”. (Pronounced suh-righties, derived from the Greek for 'heap'.) The Stanford Encyclopedia of Philosophy describes it this way:
“The sorites paradox is the name given to a class of paradoxical arguments, also known as little-by-little arguments, which arise as a result of the indeterminacy surrounding limits of application of the predicates involved. For example, the concept of a heap appears to lack sharp boundaries and, as a consequence of the subsequent indeterminacy surrounding the extension of the predicate ‘is a heap’, no one grain of wheat can be identified as making the difference between being a heap and not being a heap. Given then that one grain of wheat does not make a heap, it would seem to follow that two do not, thus three do not, and so on. In the end it would appear that no amount of wheat can make a heap. We are faced with paradox since from apparently true premises by seemingly uncontroversial reasoning we arrive at an apparently false conclusion.”Of course the sorites paradox can be run in the other direction too. If you start with a heap, and take away a grain at a time, you can end up proving that any amount of wheat, even a single grain, is a heap.