Which is it? or are both equally true?

For some odd reason these two expressions popped into my head during my walk on this very fine autumn day. I'm not even sure what I'm asking, but for some reason it didn't seem possible for both to be true...and then my head started to hurt. Tell me what you think.

"If you are not for me, you are against me."

"If you are not against me, you are for me."