Clearly you are a theorist and not a practitioner. Dealing with the real world is far more complex than simply a YES or NO. Take a look at something called 9 valued logic - it will blow your mind if you are unable to handle 3 valued logic.
Don’t get me wrong - theory is important. The models that you develop though are only an approximation of the real world.
Well FWIW the real theorists would be utterly offended if they knew I was being put in the same league as they.
The way I see it there are practitioners who care about theory (and take the bother to try and understand some of it, and even more so the consequences on their practical tasks) and there are those who don't.
(Aside : the world of fact-oriented modeling and especially FCO-IM - that's communication oriented modeling - has this stance that our databases are actually not modeled according to how the world is, they are modeled after how our comunications about the world are. An interesting distinction you might want to ponder a bit more deeply.)
Don’t get me wrong - theory is important. The models that you develop though are only an approximation of the real world.