The Caring Diagram

Someone at work was discussing something with me today and I made the comment that there was no possible way I could care any less about the topic.  Actually, it was more of an announcement on my part.  My boss challenged my claim, saying that mathematicians once thought zero was the lowest number possible.  Then low and behold, negative numbers emerged.  Therefore, he posited, there is no way that I could say with absolute certainty that I could not possibly care less.

I decided to draw the diagram below to illustrate my point more clearly.

If one were to assume a scale of caring, shown in black, where caring more follows the positive X-axis, my level of caring would be where I've noted it in blue, down near zero (but not on zero). Thus, while there exists capacity to care both more or less (especially if we assume negative caring is possible), I have taken the position--with the blue arrow--that I can not and will not care any less, despite the capacity to do so.  

I hope that clears things up.  And if it doesn't, I really could not care less.