Debate, without rebuttals, would merely be a series of speeches with no relation to each other. Like ships passing in the night, there will be no clash, no conflict and ultimately, no debate. Rebuttal, like argumentation, is one of the foundations of debate. What is rebuttal then? It is a speaker saying that an opponent's argument is not valid and showing why it is not valid. If argument is about building logic links in a case, then rebuttal is about the breaking of these links.