I mean they know in the sense that they can point to any random object and say "that object is sentient" or "that object is not sentient." We cannot articulate

I mean they know in the sense that they can point to any random object and say "that object is sentient" or "that object is not sentient." We cannot articulate the definition, but the fact that when we look at something we can tell you if it's sentient or not, implies that we know what sentience is.