Sam Enright is involved in innovation policy at Progress Ireland, an independent policy think tank based in Dublin, and he also manages a publication titled The Fitzwilliam. Most notably, on his personal blog, he curates a well-received link roundup; the following is a condensed version of his Links for April.
Blogs and Brief Links
1. We bid farewell to Robert Skidelsky. Regrettably, my interaction with his work has been limited to the abridged edition of his extensive works on Keynes, which, it turns out, are not easy to come by in paperback. Someone really should consider a reprint. Hereâs a notable excerpt from Skidelskyâs Money and Government (2018):
Ronald Coase recounted how the English economist Ely Devons told him, âIf economists wanted to study horses, they wouldnât observe horses in the wild. Instead, they’d sequester themselves in their studies, pondering, âWhat would I do if I were a horse?â and soon arrive at the conclusion that they would maximize their utilities.â This jest encapsulates a deep insight into the economic methodology.
Stumbling upon this quote while perusing Rebecca Loweâs reading listâthe first entry being an essay by T.S. Eliot on literary criticismâwas quite the delight. Rebecca encountered it during a mini-conference in St. Louis, Missouri, organized by Sebastian Garren, which, I must humbly admit, drew inspiration from the Fitzwilliamâs Milton Friedman conference. My emoji usage is sparse, but: đ„č
2. David Friedman responds to my piece on his father. Most sourcesâincluding biographies, Wikipedia, and The New Yorkerâclaim Milton Friedman stood at a diminutive five feet. David counters, asserting his dad was 5â3â, and Iâm hardly in a position to dispute this. What gives? There are countless photos of Milton alongside individuals of known heights, and three inches isnât exactly negligible. This seems like a significant oversight. Furthermore, for those who felt I was unnecessarily harsh in my initial post, I only mentioned Miltonâs height because he genuinely seemed to take pride in it. Short kings deserve respect.
3. Gavin Leech discusses the current state of Chinese AI. He concluded that thereâs about a yearâs lag behind Western developments; however, given the post was penned in November 2025, he admits itâs likely outdated by now. Still, itâs worthwhile for its insights on how China ‘distills’ knowledge on cutting-edge models from the open internet.
4. Nicholas Decker argues that Steven Berry, Jerry Hausman, and Ariel Pakes should have been awarded the Nobel Prize in economics. This is also a good read for those seeking to grasp the Hausman test in fixed versus random effects estimation within panel data, which admittedly flew over my head as an undergraduate.
5. Stephen Malinaâs links are worth exploring. My favorite entry features Afra Wangâs piece on a Beijing vibe coder. The quote from Liu Xiaopai strengthens Dan Wangâs hypothesis that âno two peoples are more alikeâ between Americans and Chinese:
Over two decades spent creating software have drawn profound inspiration from Paul Grahamâs Hackers & Painters. Graham posits that software is the best business due to its marginal cost nearing zero. Software creators, akin to painters, engage in creation rather than mere construction labor. These ideas have significantly shaped my approach. I also appreciate Tools of Titans and Tribe of Mentors by Tim Ferriss.
6. A comprehensive archive of books mentioned on the Conversations with Tyler podcast.
7. Shruti Rajagopalanâs insights on Delhiâs recent AI Summit are not to be missed. Her Substack and podcast are essential resources.
Music and Podcasts
1. Tyler Cowen and Alex Tabarrok delve into the history of options pricing. I was particularly struck by the tale of polymathic (often French) economists whose pioneering work went unrecognized by (predominantly Anglo) economists due to a lack of mathematical understanding for decades. For instance, Augustin Cournot was applying the concept of Nash equilibrium back in the 1830s. Louis Bachelier derived the equations for Brownian motion a mere five years before Einstein rediscovered them independently and had sketched the foundational framework of Black-Scholes theory over seventy years earlier.
2. Joe Studwell discusses African economic development. I have yet to read How Africa Works, but it’s on my list; perhaps we can organize an African economic development edition of the reading group.
3. Rebecca Lowe and Tyler Cowen engage in a discussion about the definition of freedom. The podcast features a lively format where the host and guest strive to arrive at a workable definition of a philosophically rich term. If I were to grace such a podcast, Iâd find topics like âalignmentâ or âcausalityâ quite intriguing.
4. Talking Heads’ Speaking in Tongues is a must-listen. My favorite track is Moon Rocks, while This Must Be the Place leaves me a bit underwhelmed. Notably, Brian Eno did not produce this album, having been the driving force behind the previous three, which apparently led to some behind-the-scenes tension.
5. The Clashâs Combat Rock has drawn criticism for being less robust than either London Calling or The Clash. Nevertheless, Rock the Casbah is a standout track, and now seems an appropriate time for satirical takes on Ayatollah Khomeiniâs decrees. Interestingly, I learned that Straight to Hell serves as the Vietnam protest song sampled in Paper Planes, which is rather cool.
6. The Mingus Big Bandâs The Charles Mingus Centennial Session is a remarkable tribute. Charles Mingus, an iconic figure in jazz, inspired this ensemble established by his widow over a decade after his passing. The opening rendition of Work Song (Break the Chains) is particularly powerful, though it is distinct from the Nat Adderley jazz standard. Interestingly, the trombone player on this album is renowned internet public intellectual Coleman Hughes. What can we deduce from the fact that individuals who attain success often excel in seemingly unrelated fields?
Books and Papers
1. Dave Donaldsonâs Railroads of the Raj: Estimating the Impact of Transportation Infrastructure stands out as one of the most remarkable economics papers of our era. Hereâs Kevin Bryan articulating why Donaldsonâs John Bates Clark Medal was well-earned. This paper, part of his PhD journeyâwhich took an astounding eight yearsârequired manually digitizing 1.5 million data points from mostly handwritten colonial archives. Using this data, he assessed transportation costs in British India by analyzing local fluctuations in salt prices, a highly uniform commodity. Understanding the costs at one location allows for insights into the transportation expenses between various regions. Donaldson estimated a parameter Ξ, measuring the elasticity of trade volume to price changes. By integrating this information with a standard general equilibrium model of trade, he could provide a precise estimate for the welfare impact of railroad expansion during the Raj.
This approach is undoubtedly innovative; however, the endogenous nature of railroad placement poses a challenge: could it be that railroads were constructed only in thriving regions that would have prospered regardless? A stronger case would be showing that equally viable railroad sites, which were not developed for arbitrary reasons, did not experience similar benefits. Donaldson employs the Kennedy plan (1848) and the Lawrence plan (1869) as reference points for railroad expansion in India. This constitutes a placebo testâa term that, interestingly, has little to do with its psychological counterpart. This facet of the paper is arguably the weakest, as itâs possible that the cancellation of planned lines occurred for unrelated reasons, resulting in those regions experiencing lower incomes.
2. In Railroads and American Economic Growth: A âMarket Accessâ Approach, Dave Donaldson and Richard Hornbeck revisit Robert Fogelâs classic 1964 study on railroads in American economic history, which contended that they were not crucial for 19th-century growth. Fogel applied a methodology known as âsocial savings,â whereby he evaluated the quantity of goods transported by new technology and calculated the costs using the next-best alternative. His findings revealed a surprising degree of substitutability among railroads, canals, and other transport modes. He concluded that the absence of railroads in 1890 would have resulted in only a 2.7% decline in GNP, a figure significantly lower than expectations at the time.
3. Tyler Cowenâs The Marginal Revolution: Rise and Decline, and the Pending AI Revolution is more of a monograph than a traditional book, and can be read for free here. Iâm still grappling with how to leverage Tylerâs AI integration effectively beyond mere uploads of EPUBs to Claude for questions.
The first section of The Marginal Revolution provides an intellectual history of the âmarginal revolutionâ in 1870s economics, spearheaded by William Stanley Jevons, LĂ©on Walras, and Carl Menger. A Hollis Robbins review succinctly summarizes:
In the 19th century, as statistics advanced, two phenomena emerged: first, marginalismâthe notion that economic value derives from the effect of one additional unit under constant conditions (e.g., an extra loaf of bread or an additional hour of labor); second, averageismâthe view that aggregates are best depicted through averages, with groundbreaking ideas such as Adolphe Queteletâs âaverage manâ and William Stanley Jevonsâs calculations of index numbers and average consumption across populations. Tyler posits that marginalism and averageism are interlinked methods that evolved together, with averages becoming central to measurement while marginal reasoning aids in interpreting those measurements. The marginal unit only holds meaning within a distribution, and the distribution gains significance because marginal changes can be inferred from it. Tyler posits that the forthcoming AI revolution is bringing averageism back into focus.
Chapter three tackles the delayed emergence of marginalism, a concept that, while obvious today, took time to mature. Tyler likens economics to geology and evolutionary biologyâfields that are conceptually straightforward yet historically sluggish in their progression. He also makes a sociological observation that, given the shared understanding of marginalism among competent economists, the competitive landscape shifted towards more technical areas, like econometrics and meticulous empirical analysis.
Additionally, he discusses precursors to marginalism, such as Jules Dupuit. Notably, many principles of marginalism were independently articulated by the Irish polymath Dionysius Lardner in his 1850 work on railway economics (!!!). Itâs bewildering that this never surfaced during our Irish railway economics event. Should anyone wish to explore this figure for The Fitzwilliam, kindly reach out!
One fascinating detail (page 43) is that:
In the 1860s, Jevons created a Logical Abacus, sometimes referred to as a logical piano, an early computer capable of executing some logical operations faster than humans. It is currently housed in the Museum of the History of Science at Oxford University.
As is often the case with Tyler, discerning his underlying message in this book proves challenging. Hereâs what I gathered: the âmarginal revolutionâ rendered the economy seem much more comprehensible and intuitive than it truly is. While sophisticated economic theories can be effective for a time, they ultimately lose their predictive capacity. For example, the capital asset pricing model (CAPM), the most influential asset pricing model of the 20th century, includes a key parameter ÎČ, which measures an asset’s sensitivity to market portfolio movements. Recent literature, culminating in Fama and French (1992), reveals that ÎČ does not reliably predict outcomes. Nowadays, the most effective financial models are machine learning algorithms that discern statistical patterns with minimal theoretical foundations.
Two potential explanations for this are:
- CAPM was inherently flawed.
- While CAPM accurately described reality in the past, it no longer does.
Itâs a bit of both. The advent of artificial intelligence has exposed the superficiality of our previous âunderstanding.â Conversely, contrary to the pessimists, economics remains a legitimate discipline that has enhanced our comprehension of various issues. It could simply be that our world has genuinely become less interpretable over time.
Marginalism comprises mathematical identities concerning first-order conditions and optimization. Tyler dubs this âtautological marginalism.â âIntuitive marginalism,â on the other hand, posits that these tautologies hold significance and that reasoning âat the marginâ is valuable in many applications, such as in Jevons paradox. While our intuitive grasp of marginalism may falter in explaining the world, Tyler argues it will persist in the form of weights in future models (page 119):
The training of Large Language Models (and similar AI) will embed marginalism into their fundamental operating principles, as these models are trained on materials incorporating marginalist ideas⊠marginalism will endure, but it will be automated.
The Straussian interpretation of this monograph suggests Tyler is grappling with the experience of being a mid-sixties economist today, witnessing software consuming the world, including his life’s work. Many of my economist friends now wish they had pursued math or computer science in their undergraduate studies. Economics has seen various intellectual frameworks rise and fall, either because the theory was flawed from the outset or because it only elucidated a narrow range of phenomena at specific times. This includes schools that Tyler holds dear, such as Chicago price theory and Mason public choice theory. His sense of melancholy is particularly evident on page 106:
Regrettably, price theory is declining in relevance, dragging marginalism along with it. Previously, some graduate programs favored axiomatized approaches to microeconomics, while others (e.g., University of Chicago, UCLA, University of Virginia) preferred price theory. Nowadays, axiomatizations dominate almost everywhere, except at my own George Mason University.
Lastly, some amusing nuggets: regarding the notion that economics is overly mathematical, we have this quote from Shengwu Li:
âCan you provide an economic intuition for that result?â translates to âCan you explain that using math that has been a part of economics for over 20 years?â
Corollary: Topkisâ theorem counts as economic intuition, along with virtual values and eigenvalues.
Abortion statistics reveal surprising elasticity (page 31):
Data indicates that a hundred-mile increase in distance to the nearest [abortion] clinic correlates with a 25 percent reduction in abortions.
In the latest edition of âeconomists have predicted nine out of the last five recessions,â I stumbled upon the sunspot theory of macroeconomics (page 59):
â[William Stanley] Jevonsâs fascination with averages also manifested in his macroeconomic work on the âsunspotsâ theory of commercial cycles. Jevons suggested a typical business cycle duration of approximately ten and a half years, coinciding with astronomersâ findings of a similar solar cycle duration. He postulated a connection between the two phenomena, though he never successfully substantiated the evidence or causal relationship.â
For the title of Victorian polymath of the month, I nominate William Whewell (p. 103):
âAlfred Lord Tennyson referred to him as âa lion-like man.â [William] Whewell was a genuine polymath, contributing to mechanics, physics, geology, astronomy, mathematics, economics, and poetry. He served as an Anglican priest, translated works by Goethe and Grotius, and orchestrated a groundbreaking citizen science initiative to study ocean tides. He was instrumental in persuading Darwin to take on the role of secretary for the Geological Society of London, emphasizing geologyâs critical role in Darwinâs theory of evolution. Regarding the philosophy of science, Whewellâs major work was his 1837 multi-volume History of the Inductive Sciences, from their Earliest to the Present Times, now largely forgotten outside academic circles but profoundly influential during his time. Whewell also coined the terms scientist (in 1833), physicist, linguistics, consilience, catastrophism, uniformitarianism, and astigmatism, an impressive list. He even suggested the terms anode, cathode, and ion to Michael Faraday.â
Films and Videos
1. Tom Moore and Nora Twomeyâs The Secret of Kells is an absolutely stunning animated film that tells the tale of the creation of the Book of Kells. Legend has it that St. Colmcille initiated the manuscript on the island of Iona before it was transported to Kells in County Meath during the 9th century. This film marks the beginning of a thematic trilogy centered on Celtic mythology, which I sought out after being captivated by the third installment, Wolfwalkers. I aspire to write a more extensive piece on Irish cinema, which has produced many exceptional films. A notable strength of this industry is that, thanks to our sentimental nature, acclaimed international actors often participate (presumably for less remuneration) in local projects; for instance, Brendan Gleeson lends his voice to the Abbot of Kells in this film.
