It's easy to assume that emotions have little place, if any, in thinking well. After all, an argument based on "I just feel this is the way it is" isn't much of an argument at all. So should we check our emotions at the door? To continue in How to Think , Alan Jacobs uses the example of the philosopher John Stuart Mill. He was raised by his father to be a thinker, no emotions necessary with a true Brit stiff upper lip. But as brilliant as Mill was, he reached a point of mental collapse. What rescued him from the brink was a volume of Wordsworth's poetry in which he experienced a delight that had been missing for so long. Mill's writes "the habit of analysis has a tendency to wear away the feelings... when no other mental habit is cultivated, and the analysing spirit remains without its natural complements and correctives." Jacobs interprets this as "The analytical mind constantly separates, divides, distinguishes until its whole mental wo...