Why do intelligent people deny audio differences?

In my years of audiophilia I have crossed swords with my brother many times regarding that which is real, and not real, in terms of differeces heard and imagined.
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, yet he denys that any differece exists in the 'sound' of cables--to clarify, he denies that anyone can hear a difference in an ABX comparison.
Recently I mentioned that I was considering buying a new Lexicon, when a friend told me about the Exemplar, a tube modified Dennon CD player of the highest repute, video wise, which is arguably one of the finest sounding players around.
When I told him of this, here was his response:
"Happily I have never heard a CD player with "grainy sound" and, you know me, I would never buy anything that I felt might be potentially degraded by or at least made unnecessarily complex and unreliable by adding tubes."

Here is the rub, when cd players frist came out, I owned a store, and was a vinyl devotee, as that's all there was, and he saw digital as the panacea for great change; "It is perfect, it's simply a perfect transfer, ones and zero's there is no margin for error," or words to that effect.
When I heard the first digital, I was appalled by its sterility and what "I" call 'grainy' sound. Think of the difference in cd now versus circa 1984. He, as you can read above resists the notion that this is a possibility.
We are at constant loggerheads as to what is real and imagined, regarding audio, with him on the 'if it hasn't been measured, there's no difference', side of the equation.
Of course I exaggerate, but just the other day he said, and this is virtually a quote, "Amplifiers above about a thousand dollars don't have ANY qualitative sound differences." Of course at the time I had Halcro sitting in my living room and was properly offended and indignant.
Sibling rivalry? That is the obvious here, but this really 'rubs my rhubarb', as Jack Nicholson said in Batman.
Unless I am delusional, there are gargantual differences, good and bad, in audio gear. Yet he steadfastly sticks to his 'touch it, taste it, feel it' dogma.
Am I losing it or is he just hard headed, (more than me)?
What, other than, "I only buy it for myself," is the answer to people like this? (OR maybe US, me and you other audio sickies out there who spend thousands on minute differences?
Let's hear both sides, and let the mud slinging begin!
The fact that DBT/ABX testing does not support the fact that there are audible differences between two different audio components just raises the question: what is wrong with that sort of testing?
Many years ago, I participated in an ABX test Stereophile once sponsored between two different amplifiers and was correct 90% of the time, btw.
The answer lies in phenomenology as explicated by Heidegger.
Listened to out of the context of something's role as part of a system that reproduces music one is listening to something thoroughly "broken". And all broken audio products sound the same. It takes special training to "beat" an ABX test.
I can tell you this: the "same or different" decision is made by listening with one's whole body and must be done in one, or two seconds. After that, one just hears the "broken" component.
Nietzschelover, I agree the real question is must DBT/ABX testing be invalid if it shows no audible differences.
This method of testing has flummoxed me enough to conclude the same: the test just doesn't do it for me. Discerning differences hasn't been so difficult in my admittedly sparse critical listening experience. The question of which has been superior has proven more difficult for me and has required more extended listening. (Actually, I've also thought about Heidegger re:audio, at least vaguely [e.g., "opening a world"]. To be less vague, I'd have to read him again, and that's unlikely to happen anytime soon). Anyway, this is why there are 30-day trial/audition periods, right?

Back to the original intent of the thread, I'm only mainly able to talk about this stuff with friends who really, really enjoy music. Most people I know like songs--they focus on the songs and rarely on how they sound. I do a bit of community theater, and talking to audio engineers can be very frustrating, because so many of them see it as their sacred duty to debunk flaky audiophiliac observations. To think too much about it seems silly and almost childish to them. Certainly, there's some serious audio voodoo out there, and it's nice to have clear heads with grounding in the fundamentals and hard experience to balance that out. But their general attitude seems to be that if you get stuff that's correct and set it up correctly, then everything will sound correct. Case closed. For them, "correct" is enough, regardless of obvious differences; it seems that sonic differences are tolerable as long as they aren't technically incorrect. I've regarded this as the general pov of mainstream consumers (e.i, "most people"). Audio purists are a narrow contingent.

The "zeroes and ones" argument is a bit simple, isn't it? There's error correction, timing, d/a conversion, output, etc. Does your brother regard these differences as audibly imperceptible?
My question to you Larry is How do you two get along otherwise?:) There appears to be something deeper going on than your question. If this isn't the case the only other answer, as it is to most non-audiophiles is, "it really isn't that important to me, why is it so important to you" ...(wink and smile)? Hypothetically lets say you could prove it to him with 15 people in a room agreeing with you, do you really believe at this point that he would acknowledge that he was mistaken? Sometimes we try splitting too many hairs when the answer is quite obvious. Ok, there is a difference, SO WHAT, what are you trying to prove to me? No one has ever said that to me but there have been times when I suspected it was going on at which point I drop it, why bother?
Thanks for accordance Tbg.
It remains an open question as to when DBT/ABX testing actually is appropriate, however.
To the unconvinced, I would propose that, phenomenologically, such testing is useful when the DBT testing experience does not differ from the one that is had when the object being so scrutinized is normally being utilized.
For example, this is the case with wine tasting.
No one ever asks wine tasters to participate in a DBT of wine glasses (that they could not touch), though. Nonetheless, analogously, that is precisely what is being asked of the "component testers".