Dr. Murray was not in any way discredited. He was hounded, harrassed, threatened, ridiculed and worse, but in fact his research methodology was solid, bullet-proof and indisputable. That is, to people who actually read the book, had the mathematical background to understand it, and thought about what he wrote. What he did was take a taboo subject in the US and as soon as you mention anything even slightly indicating a difference between races you are immediately labeled a racist. In his case, he offered evidence that blacks overall have a lower IQ than whites, who in turn have a lower IQ than Asians. And then he asked, is that so ridiculous? Blacks clearly are superior athletes as the NBA and NFL readily demonstrate. So if there are differences in athletic ability, why couldn't there be differences in intelligence? But, boy, was that a touchy topic. Of course there have been TV sports announcers who were fired for making the obvious statements involving race, too.
Murray survived the firestorm, unfortunately his partner Hernnstein didn't. Dr. Murray fought back with the ultimate weapon: intelligence. He's a brilliant man, fascinating to talk to, fun to read, and gives tremendously interesting seminars and lectures -- but you have to be bright enough to keep up with him. I know this is way off topic, but dang it, I've studied with Murray through several courses and I get pissed off when people who never seem to know what they're talking about, talk about him. There isn't a racist bone in his body, he's a card-carrying liberal, but one who uses his brain, which is kind of un-American anymore.