You can always be wrong. Even when it's theoretically impossible to be wrong, you can still be wrong

You missed the context, which is when someone claims "This can't be wrong." Rule #1 clearly states the definition can be wrong. On the other hand, there are different levels of wrongness. Sure, these rules are most likely wrong and incomplete, but they are more correct than having no rules at all. And the reason definitions aren't the best way to give semantics is because we already have a better semantics, namely the "similarity cluster". (Map is not the territory, etc.) But forcing someone to give a definition that follows these 17 rules gives you the similarity cluster, and avoids pretty much all of Eliezer's 37 ways of using words wrongly (See the superscripts!). There might be other ways of using words wrongly, but they're going to be either obvious or so subtle that nobody can catch them anyway.

As for why I wrote this article, it's simple: I need definitions of the things on my GTD list (in particular, I need a direct specification of what constitutes a "physical, visible action" for the next-actions list), and I recalled an EY post about definitions which was his 37 ways. But that was all about how to do it wrongly, and one of my tasks is "don't think negatively", so I rewrote it. It was and is sitting in my WhatIs:definition zim wiki page. I posted it here to get some commentary and maybe someone checking that I interpreted his points correctly, which I've been getting. (Thanks guys! :-))