Let's take a look at the first example written at the top. This is one of my favourite fallacies: 'ad hominem 'meaning 'to the man'. The teacher personally attacks the student rather than his argument. Even though it's true that the student is young and native, the teacher must always respond to the points put forward by the student regardless of his or her personal characteristics. Why? Because this is the only way to progress towards the conclusion which could be derived from the discussion.