Why do intelligent people deny audio differences?

Rsbeck, you are being needlessly ugly here.
The first things I stated about my brother, above are, and I quote "He holds a Masters Degree in Education, self taught himself regarding computers, enough to become the MIS Director for a school system, and early in life actually self taught himself to arrange music, from existing compositions,". I would tell anyone, and have, that he is brilliant in so many ways, buy typical of many non believers. I don't point this out for the personal issues, which are real, but for the whole of audio lovers who face the same, kind of, " I won't even try it, because I don't believe it" viewpoint. I am saying that ignorance, (different from stupidity) is bliss, if one deny's him or herself the opportunity to try something due to a predisposed thought process, which allows them to not believe in the possibilities that can exist. Obviously you disagree, and I respect that, butyou are missing the finer point here, or so it seems.
He's not stupid,quite the contrary; just sure that nothing that he can't understand, or explain is possible. My point is, where would we be if everyone adopted that attitude?
Only the 'dreamers' and the 'what if people' like Edison, who performed (to world ridicule as the stories go) 10,000 experiments on the light bulb, before getting it.
The Scientific Journal asked him, "How does it feel to have so many (at that time I think it was 5000)failures.
Edison, just looked at the interviewer and said, "I don't see it that way, as a scientist, I now know 5000 things that won't work. The rest is history, and of course he perfected the bulb.I am saying that my brother's attitude, represents a group of people who, if they can't explain it, won't even try it, and for all of his brainpower, would never have invented the light bulb, or whatever, and I think that's a waste of his abilities, that's all.

Being without skepticism does not render one Edison. That's a flawed argument. I don't mean to be ugly, but you posted your family squabble on a public site and asked for feedback. I'm just telling you that it seems your brother has gotten under your skin and that it seems to me like there is more to this than audio -- this seems to be a problem for you. In my experience, when someone becomes an evangelist to the extent where you want your brother to set aside his skepticism and see the world the way you see it -- it has become a larger problem than audio. You seem extremely conflicted about your brother -- that much is pretty obvious. This, to me, seems like a larger and more important problem for you to delve into rather than trying to gather like minded audio enthusiasts to side with you against your brother -- sorry -- that's just the way I see it.

If he's really a scientist/educated person, he'd get his ears checked to make sure his "measuring device" is working before espousing "nuttin but ones and zeros" efficacies.

Digital technology is one thing. How it is implemented is another. It bugs me when people pull out seemingly related facts to support his own rationalization.

I would caution that assuming that "because the human being is subject to suggestion, and can be fooled", does not equate to "the human being is always fooled by suggestion".

Simply because something CAN happen, doesn't mean that it IS happening in any particular case.

If someone hears some differences in products, it is certainly just as much of a possibility(or more so) that it is happening, as if it is not happening.

Relegating every unproven statement to the "junk bin" just because it hasn't undergone a battery of tests, is not scientific either. All scientific hypotheses come from observations, which then leads to testing. Sometimes it works out, and sometimes not. And sometimes the testing regimen is not correctly applied, or insufficient to determine the truth.

It is incorrect to state that there are no differences in audio products because of similarity of outcome in simple measurement protocols. It is well known that the measurement protocols for audio equipment are woefully inadequate and incomplete, and this is admitted and known even(or mostly) by the people who do this testing.

Similarly, with double-blind A/B testing, there are known inconsistencies, and the outcomes are determined statistically and never called "absolute", but are always qualified by statements such as "in this test, things tended to come out this way". And all these tests are clearly subject to at least as many "psycological issues" as the ones they claim to be testing.

To me, the interesting thing continues to be why the ear of the listener, his pleasure or displeasure, in the environment he uses, is considered to be the only measurement that is not "accepted" as valuable by the "scientific community", when ultimately it is the only measure that is important to the listener. It seems that some feel that the listener's pleasure should be eliminated from the criteria for buying a product, and that he should buy strictly on test results alone.

Truthfully, I don't understand the point of trying to argue and convince a listener that he doesn't hear what he thinks(knows) he hears. What is the benefit of it? If you do convince the person, and he goes out and buys the cheaper gear that you convinced him should sound as good(based on extremely rudimentary tests and alot of speculation), and it doesn't(and likely will not), then what have you done for him? Conversely, a person should not try to convince someone to buy an expensive product if the rest of his system isn't up to supporting the performance level of that product, because it won't pay off that way. In any case, I expect that the listener will use the available methods to audition the products before they buy, and utilize any 30-day money-back guarantees of satisfaction, to safeguard their investments. By doing this, there is very little financial risk(perhaps some shipping costs), and the user can determine for himself what he prefers for his system. This is what most people do, as far as I know, so what is the big deal?

Just because a person doesn't know everything about everything does not reflect on their intelligence level. It reflects their experience level on a given subject, and possibly some insight. The dangerous part comes in when a person thinks that they know everything, to the exclusion of being reasonable enough to think that there are some things that they personally do not understand, so they attribute them to "psychological effects", and make no further attempt to understand or learn, but simply dismiss to the easiest available rationalization. This is where learning ceases, and dogma abounds.

During the past several years, I've spent a large amount of time designing and building pre and power amplifiers, in an attempt to learn more about why different designs do sound different. During that time I've become more and more aware that subjective differences can arise from small (< 1dB) deviations in frequency response and also from small changes in the harmonic distortion balance. The old rule that odd is worse than even seems to hold true, particularly at high frequencies. A smoother, more velvety treble results if even order dominates and a cooler and more clinical or even harsh treble is obtained by allowing odd order to dominate. This rule seems to hold true even when distortion is <0.001%. It is also my opinion that what people are hearing when observing changes with different interconnect cables is little more than a small frequency response change due to cable capacitance. Higher capacitance can also increase the distortion produced by op-amp buffered CD players, and this distortion is generally 3rd order.

While I do believe that audiophiles can hear changes and differences that the average person cannot, I also concede that these changes and differences are often grossly overstated. Too many audiophiles seem to be caught up with small differences in sources and amplifiers. The 2 biggest contributors of distortion in any hi-fi system are : 1.) the loudspeaker, and 2.) the listening room. (IMHO)