We attribute self-awareness (or other attributes) based on the results of behavioral tests that we perform on the test subject. Assume, for the sake of the argument, that I built a machine that exhibits the same kind of self-awareness as an elephant. So it would recognize itself in a mirror test etc... So if it manages to pass all these tests, is it self-aware? According to Ernst Mach, two things that are indistinguishable by observation are actually equal.

This is essentially a part of the Chinese Room Argument: how can you draw a distinction between two things, when you cannot observe it?