My dissertation advisor at Columbia University was William V. Harris, who employed his own Ph.D. in straightforward political history to cultivate a wide range of specializations in ancient Roman history, ranging from dream culture to history of emotions, to ancient economics and numismatics, education and literacy, even environmental history. But he was originally most famous for transforming the entire field of Roman studies with work expanding on his original dissertation studies in Roman political history, with his publication of War and Imperialism in Republican Rome. One of his many points of valuable advice to me was this: when you write a book on a topic, make sure it is so thorough and well-cited as to become required reading in the subject for decades; in such a way, even, that even after it may become obsolete, it will still be necessary to read, owing to it remaining the most comprehensive treasure trove of essential sources, evidence, and analysis that even opponents of its thesis must study. (Close readers of my catalog will recognize how well I took this advice.)

But the relevant point for today is that the crucial innovation Harris advanced in War and Imperialism (and conclusively proved there by marshaling an overwhelming collection of evidence for it) was to debunk what was then the going mainstream consensus in the field of Roman Imperial studies that the Romans just “accidentally” acquired an empire merely by defending themselves against attackers so successfully. Called the Defensive Empire Thesis, I remember still being taught this in high school in the 1980s, a decade after Harris published his decisive refutation of it (it takes quite a while for a new paradigm to take hold among the expert community; and quite a while more for that new paradigm to finally filter down into high school textbooks). The original notion was that the Romans kept getting attacked and betrayed, so they “had to defend themselves,” and in the process just “ended up” occupying, so as to pacify and shut down threats from, hostile neighbors; “neighbors” eventually meaning the entire Mediterranean and most of Europe, including even England (and attempts at Ireland). You know, those island guys who live right next to Italy and pose such a threat to it. Harris proved that in fact the Roman Senate had long cultivated specifically the strategy of instigating wars of self defense specifically as a pretext to assemble and govern an empire. In other words, it was all just a strategy of conquest. In the process Harris also demonstrated that the Romans from the earliest periods recorded were fundamentally, at every level, a militaristic culture entirely constructed around the ideal of foreign dominance, and maintained a cultural strategy of such for centuries. Harris has since distilled this monumental academic work for a wider audience (and expanded it to cover the entire history of the Empire) in Roman Power: A Thousand Years of Empire.

This did piss off a few people. #HistoryMatters. The Defensive Empire Thesis was popular among modern war-hawk politicians who, you know, kind of liked the idea. It could be deployed to “explain away” all kinds of uncomfortable things, from the entire Cold War (we “had” to invade Vietnam and fund proxy wars in Afghanistan and Central America; it was “self defense”), to how a baker’s dozen of Eastern sea colonies became a Mighty Empire of Fifty States by conveniently “defending itself” from coast to coast—and even all the way to frickin Hawaii—against all those unruly “savages” occupying it. All while comparing ourselves to the Glorious Roman Empire. Mr. Awesome, high-five Mr. Awesome. The same principle was even still used to justify our second invasion of Iraq; “defensive war” being promoted by neocons to shore up control of the oil market even after the “excuse” they were selling had long been debunked by actual experts as just that kind of bullshit. Voters who went through high school before the 90s were prime targets for that rhetoric. After all, this is what they had been taught. They never got the memo, “concept rescinded.”

I’ve discussed before how consensus in history changes all the time. And this requires admitting a consensus can be wrong (see On Evaluating Arguments from Consensus and Efraim Wallach on Old Testament Studies; and, related to today’s topic, my survey of the consensus-change in ancient history with respect to our understanding of science & technology in Ancient Industrial Machinery & Modern Christian Mythology). One prominent example is in ancient economics, in particular Imperial Roman economics.

The Paradigm Shift

The original consensus, developed in the early 20th century, held to a few tropes: the ancient economy was primitive and simplistic, lacking all the amazing developments in the Renaissance (or even Middle Ages) deemed formative of the modern Age of Empires; this was because the ancient mind was saddled with primitive thinking and “mental blocks” preventing them from discovering obvious things like insurance and credit and venture capital; including a class mindset that “separated” intellectual educated thinkers (“bookworms”) from actual practical makers and doers (“craftsmen”) thus ensuring they never worked together and thus never learned from each other and thus never put two-and-two together in respect to economics and industry (or science at all); part of which resulting in (or from?) their dependency on slaves, which stifled and discouraged innovations in productivity. Every single thing I just said is false. And has been proved false, completely reversing the consensus of old, into a completely new paradigm today. This transformation started with rebellious scholarship questioning it in the 90s, culminating in a windfall of such consensus-challenging studies in the first decade of the 21st century. That new paradigm is now the new consensus. And as with the Defensive Empire Thesis, the memo still has not gotten to everyone; as it depends on how much one is even paying attention to the latest developments in a given field. But all the actual experts in ancient science, technology, and economics are well on board now.

I cite a lot of this new scholarship, and summarize and describe their case and the abundant evidence backing it, in The Scientist in the Early Roman Empire (particularly Chapter 3, “The Roman Idea of Scientific Progress,” as economic and technological progress is tied up with the question of scientific progress, so I address all three). And I debunk current Christian attempts to pretend this consensus change has occurred in “Christianity Was Not Responsible for Modern Science” in The Christian Delusion (with further support from my article on “The Dark Ages” in Christianity Is Not Great). But in SERE I show in empirical detail why the Slavery Thesis is false (pp. 250-53) and the Snobbery Thesis is false (pp. 409-41). Slavery actually benefits from advances in productivity, it does not by itself impede them; and unlike the American slave system, the Roman slave system was specifically designed to capitalize on that fact. In ancient Rome, slaves becoming skilled and educated, and positively incentivized to be loyal and productive, increased their capital value, and Roman slave owners knew this and took extensive advantage of it. Hence we find the slaves operating a bread factory in Pompeii were outfitted with the Roman innovation of dough-kneading machines for the purpose, thus greatly magnifying their productivity (pp. 215, 236, 251; just one of many examples I outline in SERE). And freedman laws incentivized rewarding effective slaves with capitalized enterprises: an owner could increase profits by freeing a slave into a semi-indentured status, then financing their going into business for themselves (whether it be mercantile or a craft), from which their previous owner earned a profit share on the investment. Similarly, far from there being any imagined “head-hand” divide in the Roman Empire, scholars and craftsmen regularly communicated and collaborated and were often in fact the same people. Scientists and engineers who attended elite schools often came from successful working-class families, and were often even raised in a trade before going to school. Consequently, it was established practice to insist any scientist be also well trained in related hands-on crafts; that in fact, scientists who were not, could be dismissed as frauds. And in result, sophisticated technological advances continued apace (their construction of actual working computers being just a pinnacle indication: SERE, pp. 142, 147, 252, 399).

The Ancient Roman Imperial Economy

This even has a Wikipedia article now. And I provide a bibliography on the new paradigm in SERE (p. 194 n. 595). Newer works are now out showing how mainstream this is, and how sophisticated the study of ancient economics has become, such as Structure and Performance in the Roman Economy: Models, Methods and Case Studies, and the outstanding Oxford Studies on the Roman Economy series. The Oxford Classical Dictionary, the preeminent reference in Roman studies, now has entries on “banks,” “capitalism,” “credit” and “maritime loans” (the latter being the ancient invention of, yes, insurance policies, in this case on shipped cargoes; ancient burial societies were likewise de facto life-insurance companies), as well as, of course, “economy, Roman.” The Romans likewise invented the basic concept of a corporation (in the form of “capital associations” that were given formal legal status, thus even originating the concept of corporate law). And such corporations sponsored large capital business enterprises, including funding and drawing shared profits from various kinds of factories, complete with mechanical automation—ranging from ubiquitous flour factories, even automated stone-mills and lumber-mills, to the ancient equivalent of “canneries,” where managed fish farms directly fed organized factories for processing, jarring, and potting the produce for shipment. The Romans also had private and public banking enterprises, complete with legally recognized letters of credit, loan operations, even managed endowments and annuities.

There were even nonprofit credit enterprises, such as Pliny the Younger’s endowments funding schools and libraries in his home town: at his direction, his bequests were managed as a loan program to local farmers and businessmen (which would have included some women; as we have many inscriptions of women owning and running businesses), and the designated public institutions were paid for in perpetuity by the interest they paid on those loans. And this is no aberration; we have ample evidence this was a common practice all across the empire. Rome also regularly engaged state subsidies of economic infrastructure development because they knew increased economic activity increased state tax revenues. As I wrote in SERE (p. 257):

[N]either the emperor Trajan nor Pliny the Younger [in their correspondence about it] express any moral or religious concerns about a government interest in subsidizing the alteration of nature with a substantial canal project in order to improve the local economics of stone and timber transport—as well as, Pliny adds, the luxury fruit trade, even though the movement of cash crops served no direct government interest.

Even since the analysis of John D’Arms in Commerce and Social Standing in Ancient Rome it has already long been known in the field that florid literary examples of the aristocratic elite railing against money-making pursuits was mostly for show: the elite (Seneca included, the man usually quoted) routinely pursued profits through often massive enterprises in trade and industry and even the much-maligned “usury” (i.e. offering loans and credit). They relied on trusted intermediaries of lower status (often, indeed, their own freed slaves, as I noted earlier) to manage their commercial and industrial assets and banking contracts; but there was never any reason to believe they were in any way aloof to how their business managers were disposing of their capital investments. And since the 1990s, extensive proof they were very much involved has been assembled, from papyri, epigraphy, and archaeology, as well as a more careful study of those same literary sources, and others.

Indeed, as I show in SERE, when we actually read, for example, Seneca’s drunk-uncle rants against luxury, vanity, and profit-seeking in his society (including the invention, production, and regular consumption of sheer garments, glassware, stage elevators, automated air perfumers, mechanical organ tuning shops, year-round ice vendors, production hothouses, and high-rise apartment complexes), the things he complains about entail a rather massive, sophisticated, commodity-based economy was thriving all around him. He just didn’t like it. Rather like a FOX News pundit declaring themselves “shocked, shocked” that poor people own refrigerators (well, “have access to” would be more accurate—most poor people’s refrigerators in America are the property of their landlord). Their rant is less indicative of the power of the American economy than the seemingly incidental facts “shocking” them, which tell a very different tale. The same can be said of “urban legends.” For example, in the 1970s we had the “urban legend” that oil companies were assassinating suburban inventors of car engines that run on water. No historian thousands of years from now should believe those legends; but rather, the legends themselves indicate how sophisticated the American economy had by then become.

The Romans had their own version of this myth, for centuries telling tall tales of the state murder of the humble inventors of “unbreakable glass” (in its most ridiculous form, the material imagined more closely fitted the Star Trek fiction of transparent aluminum), for fear that it would drive down the price of silver—a tall tale becoming for some authors even a point of comedy. As with “water-powered cars,” there was a vague kernel of truth behind the legend: blown glass had recently been invented in the early 1st century by enterprising Syrian (or possibly Jewish) Romans, and its ability to flood the luxury market across the entire Mediterranean with elegant blown glassware was perceived by some “drunk uncles” of the time as a threat to silverware (“If kids these days start buying glassware instead of silverware, my precious metals contracts will plummet!”), which, unlike glass, can have dents repaired (while glass could be melted and remolded same as silver). It makes no sense economically (the use of silver on tables hardly impacted the values market for the metal), but it makes just enough sense economically to tell us something about the times: people actually understood how economics worked, well enough that the more stupider among them got it wrong (think, “water powered cars”), while the smarter among them were making bank on the same concepts.

For example, it was readily understood that blown glass generated far more economic opportunities than tableware. It was very quickly sussed that blown glass could be rolled into remarkably clear and thin “panes” that we now call “windows,” resulting in a heating revolution in the energy market. As I put it in Scientist (pp. 218-19):

A market soon grew in blown glass cups, jars, vases and other containers. Around the same time, rolled glass was developed, and thus window panes, frosted glass, and swing frame windows appeared on a more significant scale, an often-overlooked advance in heating technology (allowing solar heat to enter a home or building while preventing the warmed air from escaping). Both markets led to the development of substantial glass factories in Roman Germany (and possibly elsewhere) by the 2nd century A.D. Glass mirrors had [already] been introduced in the previous century. Glass lamps and streetlights eventually followed, though it is unclear when. In any case, [we know] lanterns with transparent casements of glass, soapstone, skin, parchment, or horn, were certainly in use by the 1st century A.D. [Blown glass also found its way into advances in scientific instruments.]

Of course I give many more examples in Ancient Industrial Machinery & Modern Christian Mythology. And a great many more examples in The Scientist in the Early Roman Empire. For example, I discuss “Hero’s coin-operated vending machine,” a Roman-era invention based on earlier Hellenistic machinery. In his treatise on water-and-air-powered machines, Hero of Alexandria explicitly says all he lists are actually pieces of machines, individual components, with example uses, not exhaustive accounts of all their various applications, explaining that engineers can assemble his components into many diverse complex systems of machines to satisfy all manner of clients’ needs—which needs were always, in some sense, economic. For example, Hero’s sample use for his vending machine is for dispensing fixed quantities of holy water to temple visitants (one coin inserted, produces one small container’s worth of blessed water). Which, I note in SERE (pp. 224-25):

…is worth bringing up again as an example of technological ingenuity serving the purpose of profit and efficiency. The machine Hero describes was apparently invented to relieve temple custodians of the laborious task of selling fixed quantities of holy water to pilgrims and supplicants, thus permitting a substantial increase in sales through mechanization. This would seem to be a case of a scientific engineer contracted by a business to produce a machine that would reduce labor and increase profits. It hardly matters that the business in this case was a religious operation, rather than industrial or agricultural.

After all, as atheists have long been pointing out, religions are business enterprises. They are profit-earning companies that sell products and services, which merely “claim” to be “not for profit” (a claim belied by their executives’ private luxury jetliners and elaborate mansions and designer clothes). In antiquity, temples were even some of the most commonly available commercial banks (they managed deposits and ran loan programs with both their own and their customers’ holdings). After all, with all the votive gifts temples accumulated over the years (ranging from straight up cash money, to such weird gifts as a golden foot in honor of a prayer-healed ankle), they became some of the largest holders of investment capital; and were often the best-guarded and most safely-built institutions for the purpose (indeed, the modern word “museum” comes from the ancient word for Temples to the Muses, goddesses of the arts and sciences, which per their subject of patronage often accumulated famous and eventually antiquary paintings, statues, and other curios they could put on display to wow pilgrims and local investors alike). These businesses were as interested in increasing the productivity of their labor force as anyone else. Ergo, temple vending machines.

This doesn’t mean they had “all” the economic advances we now enjoy. Obviously not. Ancient capitalism was less developed than Renaissance (and thence modern) capitalism eventually became. But capitalism it was. The first publicly traded corporate stock was the Dutch East India Company in the 17th century, and that was only a gradual development from simpler commodities stock and bond trading developed (likewise in Amsterdam) in the 15th century. But these are extensions of and innovations upon the core concept of capitalism as the ownership, transference, valuation, and accumulation of capital. Hence ancient venture capital corporations were not based on a concept of stocks and shares, but were based on a conception of capitalism. Which notions we see bowdlerized in those urban legends about the economic effect of glassware on the capitalization of precious metals, alongside the real-world capitalization of extensive glass factories in search of ever-new-and-multiplicitous markets and applications for its products. Which entails a great deal else; for example, developing and optimizing an extensive infrastructure of cargo transport—of delicate products made of glass even.

Likewise, the explicit study and theory of capitalist economics did not arise until even later than the invention of corporate stocks and shares, with the seminal Enlightenment work of Adam Smith in the 18th century, which is so modern it post-dates by half a century the invention of even the industrial steam engine. Nevertheless, Smith did not come up with his ideas out of nowhere. A disorganized assembly of similar notions about the use and maximization of capital dates all the way back, at least, to the ancient Roman Empire. This is evident even in the most likely answer to why steam power was never exploited until shortly before Smith’s time: it was obviously too inefficient to even contemplate. The Roman Empire did experience its own Industrial Revolution, based on the exploitation of water power. And that wouldn’t have happened if they did not recognize that water power was substantially cheaper than human and animal power. And this is a logical, capitalist assessment. Which was plainly made at the time; as the Romans had steam power, and all the components necessary to launch a steam revolution had they seen any sense in it.

Yes, the steam engine (and eventually internal combustion engine) allowed a much greater release of anciently stored energy for industrial and everyday use. Per the analysis of Bradley Layton, “the average energy densities” for flowing water as a power-source “are closer to one-half of a joule per cubic meter to fifty joules per cubic meter,” whereas “a single gallon of gasoline contains approximately forty megajoules of chemical energy,” and though the energy return on investment is larger for water than fossil fuels, water power is far less available, and almost never available in comparable quantity. Which is why we can’t convert our fossil fuel economy back into the Roman-style water-powered economy. But this is after centuries of technological refinement. Anyone unaware of that potential will immediately see steam power as, to the contrary, an enormously cost-inefficient power-source. Just compare how much “fuel” you have to feed a primitive steam-powered pump (of the kind first invented), and what that would cost, to how much “fuel” you’d have to feed a human or animal to continue working the same output eight hours a day. Steam comes out as an absurd waste of money; literally the most inefficient solution to industrial power imaginable. No rational person would even think it worth the bother.

Steam was exploited commercially in the Roman Empire (Hero describes inventions of steam-powered robotics for the wowing of temple crowds, and the crude powering of an automated billows), but not industrially, most certainly because, as I just pointed out, it was too expensive. Steam engines only became efficient to conceive when they were needed to drain coal mines, the actual occasion of their invention, because that made the cost of running them negative (Savery’s pumps literally produced more coal than they burned)—which circumstance did not arise until the 17th century (the time by which coal had been mined all the way to below the water table). Once the machines existed, improvements on their efficiency could begin, and eventually an unexpected outcome could be realized: the machines became more cost efficient than human and animal power. Then it made sense to retool an entire nation’s industry on the basis of this new technology. The Romans otherwise had invented all the required components and fully understood steam as a locomotive force (SERE, pp. 232-34; and index, “steam engine”), and some even of the underlying science—they did not yet hit upon Boyle’s Law but they knew heat caused gases to expand; and cooling, to contract; and more or less why (Ibid., pp. 157-58). But they were no more able to “psychically” foresee an efficient steam engine than the eventual inventor of the steam engine himself was. But they did see (because they did not have to foresee) the efficiency gains water power afforded, and they exploited it extensively, through their equally extensive use of investment capital. That’s capitalism.

Conclusion

In this case the old consensus was based on bad methods (which only began to relevantly improve after 1950, while the new improved methods only came to be applied to these particular questions after 1990), combined with a number of stubborn presuppositions, exacerbated by a substantial lack of data (tremendous advances in archaeological discovery and synthesis since have contributed a vast new database of information about the ancient economy). As we learned to look at literary texts with less gullibility and more sophistication, especially in respect to “reading between the lines,” we began to extract more, and more accurate, information about the ancient economy. Likewise when we started applying sophisticated new tools in quantified economic analysis (ranging from ice core data to simply counting the number of nails recovered from the ashes of Pompeii). Which ultimately forced us to abandon cherished presuppositions distorting our reading of the evidence, presuppositions that we really never had any evidence for to begin with.

For example, in respect to the urban legends about glass: previous historians literally mistook jokes about this nonsense as historical reports, either as narratives of events that really happened, or that didn’t but were actually believed by the authors who were in fact making fun of them (I’m not kidding: see my historiographic analysis in SERE, pp. 288-90; cf. pp. 273-76). A serious methodological fail, rooted in unfounded presuppositions about ancient “primitiveness” and what various authors “must” have been thinking. At the same time, historians and archaeologists realized they should start asking what should have been obvious questions about the physical evidence: if so much blown glass is being found everywhere and mentioned everywhere, and popping up in so many forms and uses, and we’ve found a massive production facility for it even as far out as Germany, where was all this blown glass coming from? How was it being transported? Who was financing all this? The evidence entails a massive commercial and capitalist economy—just for glass. Multiply by hundreds of other products, and things start to change quite abruptly in how we understand the ancient world. At a 2nd century Roman fortress in Scotland we found they had a warehouse containing almost a million iron nails, consistently manufactured into six different specialized types. You have to explain who made those nails and how they got there, as well as how all six types were invented and developed, and once known-about, ordered. You have to account for all the mining of ore and processing; the fuel burned to forge them; the personnel dedicated to making them, and to transporting them across the whole empire. And then you have to do the math: how much all this cost. And yet it was a throwaway supply item; a mere trivial standardized outfitting of any Roman fort. Multiply that fort by all Roman forts. Just with nails we start to see the massive sophistication of the Roman economy.

In this case the consensus was so rapidly and overwhelmingly overturned by the vast amount of evidence that was able to be recovered, and the absolute clarity with which we could show previous methods of studying the pertinent artifacts and literature, and even of just reaching conclusions in general, were so incompetent. Not all consensuses that should change will enjoy such an onslaught. In Biblical studies, whether the hypothetical Q document or Jesus existed are not likely ever to enjoy any such decisive turn of evidence. For Moses, it took decades, and still fundamentalist scholars can’t accept it. For Q and Jesus the evidence is extraordinarily scant, and wholly problematic. Which is why any position on them can be defended so easily to the satisfaction of anyone’s desperate intuition. It ultimately comes down not to new evidence (there is unlikely ever to be any) but to whether those studying these subjects will ever admit the methods they are relying on are just as incompetent (or incompetently employed) as the methods used to defend the old paradigm in ancient economic history.

In that case we had the advantage of being able to decisively prove those methods incompetent by overwhelming physical evidence. But if we had not had that, the old paradigm might still reign, as defenders of the status quo refuse to accept any logical argument for the ineptitude of their methodologies, and despite a lack of good evidence even for their own position, they nevertheless “rationalize” it with a specious use of what scant and problematic evidence does exist; or even, as often we catch them doing, evidence that doesn’t even exist (or worse, by denying evidence that does). This may be a problem peculiar to Jesus studies, though as Thomas S. Kuhn observed, as likewise David Hackett Fischer (specifically for history), it probably isn’t.