I Don't Know Jack

From HunterWiki

It's not that I haven't met him, I have. I maybe can even recall the conference that I met him at, or whose friend he is, or that he is the parent of one of my kid's school-mates. I met Jack, but I don't know Jack, and I can't remember his name.

However, what I find truly incomprehensible, is that I know for a fact, I know with an absolute surety that his name isn't Jack!

How can I know his name isn't Jack if I can't remember his name?

I know his name isn't Sue, but that might simply be deductive reasoning, as it is highly unlikely that his name would be Sue (no matter what the song says). I might even know that his name is not Mahatma, or Vladimir, they too being improbably in this area. His name is a perfectly average and normal name for this area and demographic, and I can't for the life of me remember it. But I know it isn't Jack.

How can that be!?

If I was writing my brain algorithm to determine if I had someone's name right, the code would need to look something like this:

function IsNameCorrect(person, possible_name)
{
   if(possible_name != person.name)
      return false;
   else
      return true;
}

Now you may have to understand some JavaScript syntax to get to the bottom of that example, but the key line is line 3:

if(possible_name != person.name)

(the != operator means: not equal)

In order for this function to return false (which it does), the condition which is executed must know 'person.name' (the dot denotes that name is a 'property' of the 'person' entity). But if I know person.name enough to have my mental IsNameCorrect function return false, why can't I recall person.name?!

The answer to the mystery awaits your insight...