The
well-known (and
oft-misunderstood)
Schrodinger's Cat theory is said to
state that a cat, when placed in a
box and the lid closed,
exists in a state that is neither
life nor
death, but somewhere in between, and that its
nature is not determined until the box is
opened. (This is actually wrong, but a detailed explanation is not the purpose of this
missive.)
I present to you the theory of Schrodinger's Momma.
"Yo' momma is so fat," "Yo' momma is so ugly," "Yo' momma's teeth are so yellow," etc. These are common sayings (not so common anymore, really).
When you insult someone's momma, you are not really insulting their mother. You are insulting a sort of meta-momma, if you will. This meta-momma is indeed, all of these things. Perhaps even all at the same time.
However.
Imagine the following conversation:
Person A: "Man, yo' momma is so fat, she plays pool with the planets."
Person B: "Shit, bro, at least my momma can get a damn job."
Person A: "How does she find the time when she's so busy CONSTANTLY SUCKING MY WANG?"
Now, obviously Person A does not want it to become thought that he constantly receives oral sex from someone who is afflicted with obesity, so Schrodinger's Momma exists in a null state until the box is opened, as it were, and she can become the entity capable of being the target of the insult.
It is in this way that you can yo' momma your best friend, your brother, your father, and anyone else up to and including your mother, with no bad blood between you and the insultee.