I'm no expert, but ... perhaps it is true that everything that can be heard can be measured, someday. But now? I'm not so sure. Before TIM was measurable, people heard expensive solid state amplifiers that sounded bad and were mystified, because these amps sported .001% (ordinary) distortion. The "Golden Ears," talk about many sound qualities for which they don't have measurements. Even though I suspect that much of this is placebo effect, illusory, and in the category of the emperor's new clothes, some of it may be real, and constitute kinds of distortion we have neither names nor measures for.
I think even Thorndike thought that we would have to wait a bit before all things are measurable.