In a one last gasp exercise to transform students into thinking adults who know something about biology, we have senior seminar. Today's topic deals with how do you know something, and when it is OK to have your own opinion. And of course in science this all hinges on evidence. So to prime the discussion an essay was assigned about a 300 million year old rock. Now what makes this rather controversial is that most of the people who would deny the age of this rock are of a particular type of religious belief. Some blow back has already reached my email Inbox. So maybe it will be a lively discussion for a Monday in late February on a particularly gray day of falling temperatures all of which does so much to provide an uplifting attitude. So this will be a great day to hand back exams (mostly good, but with a few rather poor results) and essays marked up for revision (Hoo, boy, are they marked up!). This is always particularly amusing because in this day of spell checkers "they're misuses of simple words our to painful two bare even if there sound is write".