hilde45's map metaphor, and djones51's distinction between the "two systems"—"objective" measurements and "subjective" perceptions—calls to mind the Borges story "Of Exactitude in Science" (which, in its entirety, is just one paragraph long—itself a kind of pun). Borges imagines a culture that has developed cartography to such a point that their best map of a territory is the same size as the territory!
If a "better" map is one that indicates greater detail, then the "best" map would be one that left out no detail at all. But that would not be a map, it would simply be a pointless duplicate of the area mapped!
The relevance of this parable here is this, I think. Even if, in some hypothetical future, science were to develop measurements to the point that no subjective perception could not be rendered "objectively," this would still not touch what's at issue here (namely, the claim that if two things—power cords, interconnects, whatever—measure the same, then they must sound the same). If neuroscience is one day able to "map" the neural connections that objectively correspond to the experience of tasting a fine Cabernet Sauvignon, that neurological correlate will capture nothing at all of the experience of tasting that fine wine. We do indeed have two different "systems" here; even if there's some one-to-one correspondence that can be mapped, they are not ontologically identical, they belong to different categories of being.
And yet...although I can't have a pain in your tooth, if we are to discuss our preferences—which are strictly incommunicable, as they are grounded in our private subjective experiences—then we need some kind of common language. That's what science, and "measurements," purport to provide. I can't share the experience of my neural firings with you directly. But I can point to the objectively measurable phenomena that gave rise to them. Sure, wine tasting is "subjective," and so is music appreciation. But there are wines that command huge sums of money, just as huge sums of money are spent on power cords and cables, and we want to believe there's some "objective" justification for this other than simple taste and preference.
We want to believe this, but it may not be so. The differences between audio systems may ultimately be no more "objectively" constituted than the difference in preferences for Mozart and Black Sabbath. The same may be true of wine. On our 25th anniversary, a friend prepared a seven-course Thomas Keller dinner, I opened a 1988 Chateau Mouton-Rothchild I'd been holding for more than a decade, and our daughter took her first sip of wine. A great one to start with, no? We all waited eagerly to hear her opinion. She swirled, sniffed, tasted, and declared: "It tastes like wine." Indeed!
One last thing. djones51 concludes by saying that "natural physical phenomena [are] oblivious to our rules, under the right conditions electricity will stop your heart whether we believe it or not." But that's so only to the extent that electricity is obeying our rules—in this case, the rules that govern how the heart operates and how electrical current interacts with that operation. You may want to say that these are genuinely "objective" facts, but to the extent that they are observed, named, measured—in short, experienced—they, too, are grounded in subjectivity, what philosophers call "mind." Kant argues that space and time themselves are features of mind—"forms of sensibility," to be specific—and do not exist except in consciousness. In the last analysis, "objectivity" is really only universal subjectivity: what is "true for everyone" is merely that which everyone will experience in relevantly similar ways.
Now, while we don't all experience Mozart (or Black Sabbath) in relevantly similar ways, we do all experience sound waves according to the laws of acoustics and auditory perception. This is why many audiophiles insist that all music will sound better on a better system (although it is also true, of course, that, for instance, bass-heavy music will sound best on a system with especially strong bass, etc.). The laws of physics don't make the judgments of taste which a musical preference presupposes. What the audio system does, more or less well (and this should be measurable) is to reproduce the aural phenomena, governed by the laws of physics, that the recording technology committed to the original source. Are these laws also "subjective"? Well, yes, at least in so far as they depend on consciousness. But they are "universally subjective" in a way that taste is not. Science gets better and better at identifying, describing and quantifying what is universally subjective, and so, in principle the audible differences between interconnects must be "measurable," even if not yet, if they exist at all. But those still hypothetical measurements no more guarantee an agreement in preference than would a comparative chemical analysis of Chateau Mouton-Rothchild and Chateau Lafite-Rothchild.
In the last analysis, Mozart, Black Sabbath, Chateau Mouton-Rothchild and the sound the wind makes in the chimney are "enjoyable" and "valuable" only if some consciousness values them. Value is not measurable. I prefer the Jupiter Symphony to John Cage's 4'33". But there is no "objective" justification for that preference. They're both objectively "aural phenomena," governed by exactly the same laws.
