1%

Everyone who has ever lived is at least 1% persuadable.

Arguments are all around us--this is the basis of Rhetoric Theory.
People are always taking one side or the other--sometimes they do it knowingly, other times they do it ignorantly, but they always take a side.

Some people appear to be unconvincable. They seem like they will never change their stance on an arugment.

The truth is... no one is 100% firm on their opinions and stances. Everyone can be persuaded one way or another. People who seem to be 100% in behalf of their argument are really only 99%; the argument then becomes a matter of discovering in what way they can be pursuaded and whether the cost-benefit of persuading them is worth it.

Most people who are 99% aren't worth arguing with because people tend to be more firm on trivial matters than important ones, and trivial matters aren't worth arguing over.