There is no reason for this assumption though. If he says something that is not true, then he is lying even if the opposite is also not the truth.
The real question is: is he making one statement or two? I believe that he is making only one statement with two (purported) facts. If either fact is not true, then the statement itself is a lie.
If a blue duck says, “I am a brown dog,” that is just as much a lie as saying, “I am a blue dog.”
