Against Hoppe on Argumentation Ethics

Let’s say I’ve been getting bullied at school. I’ve had enough of him one day, so I say to him: “You are annoying me, so tomorrow I’m going to fight you after school.” He responds, “But you are implicitly agreeing to the NAP right now, you can’t argue for fighting me without contradicting yourself.” I respond, “I do agree to the NAP at this moment, but soon, I won’t agree. Just because I agree now by arguing doesn’t mean I agree in the future or past.”