Arguments that We Have the Original Text

When I have public debates with scholars over whether we can know the original text of the New Testament or not, I stake out the claim that we cannot, and they stake out the claim that we probably can. Part of my argument is always the one I started to outline in the previous post. If we take something like the Gospel of Mark, our first complete manuscript of Mark is 300 years after Mark was first produced and put in circulation. So how can we know if that manuscript is extremely close to the...