[JohnFen]

The problem, as usual, is that we don't have a solid understanding (or even definition) of what sentience actually is. The only thing that we can say with certainty is that we experience it.

This gives wide latitude for moving the goalposts by asserting a specific definition that is favorable to whatever it is you've built.

It gives an equally wide latitude for dismissing what's been built as not being actually sentient by defining "sentience" in a way that makes the dismissal true.