A close friend send me some pages from a book she is reading – Ministry for the Future – by author Kim Stanley Robinson, which was published in 2020. It is about an organisation that is chartered with defending the rights of future generations and they pursue various projects accordingly. Its major challenge is climate change, after a “deadly heat wave in India” and the narrative allows the author to entertain very interesting discussions about economics, ecology and society. It is classified as “hard science fiction” because while the work reflects the imagination of the author, he bases the narrative on “scientific accuracy and non-fiction descriptions of history and social science” to bring home the challenges we face with climate etc. The pages I received came from Chapter 73 (pages 365-366), which has a two-page discussion about Modern Monetary Theory (MMT). The author writes in his future scenario that “Enough governments were convinced by MMT to try it. That it influenced so much policy through the late thirties was regarded as a sign either of progress or of desperate fantasy solutions.” While the discussion is interesting, I want to focus on one of the ideas the author presents because they illustrate an important distinction between ‘Keynesian’ and ‘Post Keynesian’ thought on fiscal policy and MMT analysis.