Skeptic: No one can know the truth.
Christian: Is that true?
Skeptic: Yes, it is true.
Christian: So, one can know certain truth. In your case, it is true that no one can know the truth.
Skeptic: What if I change my answer to “No, it is not true.”
Christian: Well, if what you told me is not true, why should I listen to you.
Skeptic: Okay! But that was just my personal opinion.
Christian: Is your personal opinion true then?
Skeptic: Opinions are neither true or false. Its a free country, I am entitled to what I say.
Christian: It is a free country in a sense that you are free to speak your mind. I am just asking if what you’re free to speak namely “No one can know the truth” is true.
Skeptic: That is just your opinion of what it means by a free country. Which is neither right nor wrong.
Christian: What about my opinion of 2 + 2 = 3, is that also neither right nor wrong?
Skeptic: It is wrong, 2 + 2 = 4.
Christian: So, opinions can be right or wrong.
Skeptic: Oh! I never thought of it that way.