The works of Adam Smith are filled with quotable moments. The pin factory. The poor man’s son. The invisible hand. The butcher, the brewer, and the baker. The dog and the philosopher. The impartial spectator. The man of system and his chessboard. And our propensity to truck, barter, and exchange. All of these are so well known and so often quoted that I’ve had editors ask me just to refer to them in passing rather than quoting them in full.

But I’ve always been a fan of the weird little corners of Smith’s work. I like his discussion of why nude statues are better than statues with clothing. I like his insistence that “[w]e do not grow weary of a good flower and fruit painting,” his discussion of special effects in the theater, and every time he lets loose one of his rare humorous barbs against Jean-Jacques Rousseau’s thought or Lord Shaftesbury’s style.

So it’s no surprise that one of my favorite moments in Smith’s writing is a fragment of a letter he sent to his mother from Oxford as a young man in November of 1743. “I am just recovered of a violent fit of laziness, which has confined me to my elbow-chair these three months” (Correspondence of Adam Smith, Letter #5, 29 Nov. 1743).

If the charming archaism “elbow-chair” is insufficient to explain my love for this passage, Smith’s delightfully paradoxical phrase “a violent fit of laziness” should be self-recommending for any lover of good prose. Who hasn’t felt exactly this sensation when confronted by a pile of end-of-semester grading or an article that needs just one more revision? Smith struggled for his whole life with what the early moderns called “scholar’s melancholy” and famously warned against its dangers in his History of Astronomy.

Leave it to a scholar intimately acquainted with these sensations of disorder and disjointedness to find the words for the sensation of a lassitude so extreme it feels like a physical attack. Smith seems to have gotten up from his elbow-chair in time to avoid the “lunacy and frenzy” that follow such an attack, but he was surely aware of the potential dangers.

So in two brief lines this letter combines great prose and medical history, two of my favorite things. But it also does something else that I think is even more important. It humanizes a great thinker. It’s all too easy to think of Smith as some sort of Emersonian transparent eyeball—observing the world around him but not really taking part in it. We are tempted to imagine him producing two great works of philosophy and economics in a sort of grand solitude. And we are, perhaps, inclined to think of him as endlessly productive, constantly working, writing, and revising.

But in the same way that it is a mistake to think of Smith’s view of the market as a place that is endlessly and relentlessly productive, regardless of cost, it’s a mistake to think of Smith that way. He liked theater and dinner with friends. He liked traveling and taking long walks. Smith could even be lazy. He could be depressed and overwhelmed. He could stagnate. He could be unable to do so much as write a letter to his mother for a solid three months. But he could also rouse himself, shake off his lassitude, and get back to work.

Smith is, for the many reasons that I am certain will be amply demonstrated by other “favorite Smith quotations” chosen for this volume, an inspiration and a model for economists and philosophers. This letter, to me, makes him a model for any writer, anywhere. Don’t be ashamed of the down time you spend in your elbow-chair, but don’t forget to get up and get back to your desk.

And send your mom a note. She misses you.