I quite like this piece. I used to tell my students at the start of every term that they did not have a right to their own opinions in my classes. In fact I told them that I had no time for their opinions at all. Now, why would I say such a nasty thing? Because ‘ordinary’ opinion, not based on evidence, as in the case of taste and preference in colour, is not the same as scientific opinion, which is based on evidence and argument. Until one has ‘done’ science, one has no right to an opinion in a science class.