@gorillapaws The definitions are broad enough to allow for sapient non-humans. Which creatures might count is a subject of debate, of course, but there are some obvious examples from mythology (e.g., angels, demons, the Norse gods) and fiction (e.g., Kryptonians, Vulcans, Wookies) that make it clear we should not assume that only humans could be sapient and that humans of eras past did not universally assume that we were the only sapient beings (even if they thought we were the only sapient Earthlings).
Unsurprisingly, the real debate is about whether or not non-human animals could be sapient. Every time some scientist or philosopher has tried to draw a strict line—use of foresight, use of tools, use of language—some species has come along to challenge it (typically some species of bird or primate). But there have also been many arguments that these apparent counterexamples are better classified as proto-planning, proto-innovation, or proto-language.
While there are certainly researchers whose interest in this is purely conceptual, most of the debate is generated by discussions of moral personhood and animal rights. This means that the conversations can get a bit tied up in people’s views about the broader issues. My students have mostly managed to contain themselves, but I have been to one conference where two very well-educated adults nearly came to blows.