Almarg
I tend to agree. We don't know, and we can't know - we can only cautiously make assumptions. I reckon that is why we have to rely to some degree on what we think we hear when we listen to something, rather than expect a scientific explanation or measurement for it. For example we can do a null test on something and get a sqiggly line error function, but the debate remains as to whether anyone can hear it, and if they can then whether it is musically meaningful. The trouble is that the ear/brain is what we must satisfy, but it doesn't have a digital read-out or have consistent and verifiable results, and it is subject to error and bias. Beyond a certain point we have to design by ear, and be prepared to alter our belief-sets in response to that.