Great thread, so I thought I'd chime in as I've been part of this conversation for a while. Especially running a site named The Ethical Hacker Network
chrisj makes an excellent point. It's more that the phrase 'ethical hacker' is a subset of the larger group 'hacker.' Just like black hat or criminal hacker is also a subset. We're all hackers.
I just recently did a video for CompTIA on the basics ethical hacking. One of the areas I cover is what 'ethical hacking' is and what it is not. 2 things I mentioned in the section on what it is
discusses a) there's more than 1 accepted definition of hack as being negative. Mostly in academia. Take a look at this from dictionary.com on the def of the noun 'hack':
1. a person, as an artist or writer, who exploits, for money, his or her creative ability or training in the production of dull, unimaginative, and trite work; one who produces banal and mediocre work in the hope of gaining commercial success in the arts: As a painter, he was little more than a hack.
2. a professional who renounces or surrenders individual independence, integrity, belief, etc., in return for money or other reward in the performance of a task normally thought of as involving a strong personal commitment: a political hack
Members of the media also have their own definition with a negative connotation:
4. to damage or injure by crude, harsh, or insensitive treatment; mutilate; mangle: The editor hacked the story to bits.
And then B) When identifying themselves, criminals don't mention their subset, they simply call themselves hackers.
So add the definitions with negatives tones used in academic circles and the media (which BTW come from academia themselves) to the bad guys calling themselves hackers, and it was doomed to be hijacked.
So legitimate industry came up with a way of describing their subset. They've tried 'auditors,' 'researchers,' 'pen testers'... maybe it's simply because the word 'hacker' is sexy that 'ethical hacking' stuck. No matter what you call yourself, a rose by any other name...
So ethical is just a way of describing yourself. Apollo makes a great statement about being ethical and only experience and reputation can prove that you actually are. I don't completely agree with his art vs porn argument, but I see his point. A cert can clearly let the world know that you have a baseline of technical knowledge. But can it truly claim that you are ethical? The way I see it is that a certification attemtping to certify ethical behavior can only help the individual claim that their intention is to go down the legal path. As mentioned, experience and reputation is the only true way of proving
Then again, can't the same thing be said of the technical side? One may have the book knowledge to be able to pass a cert, but experience and reputation in the practical use of that knowledge is what sets you apart from the rest.
There's my $.02.