In Why Things Bite Back, Edward Tenner’s (1996) thesis is that changes imposed on the natural world, such from technology, produce revenge effects, unintended consequences that are generally unanticipated, often undesired, and frequently ironic or paradoxical. Per the author, it “is almost a constant … that the real benefits usually are not the ones that we expected, and the real perils are not those we feared (p. 347).” The text presents a collection of vignettes operating in reciprocity with the thesis. The thesis structures the vignettes into a history. The vignettes provide evidence supporting the thesis, which is further supported by three arguments.
Tenner’s thesis is reasonable in that it is consistent with other accepted principles. Technology plans actions to produce consequences that are intended, thus expected. Unintended consequences result from an inability to predict them. They become revenge effects by (1) failure to see that inability and (2) disjointness between expectation and outcome. Revenge effects result from a confluence of ignorance, hubris, and complexity.
Not all things are knowable, so not all things can be predicted. A base-line of ignorance is built into the structure of physical reality. Heisenberg’s Uncertainty Principle (Evans, 1955) is, in one sense, about atomic structure. But, in another sense it sets an absolute upper limit on human knowledge. In practice, actual human ignorance always greatly exceeds the limit set by Heisenberg.
It can be difficult to see the limits that unavoidable ignorance imposes on human ability as unskilled people tend to be unaware of the fact. As described by Kruger & Dunning (1999), “difficulties in recognizing one’s own incompetence” leads people to overestimate their skill. Where awareness of ignorance might lead to humility, some hubris is intrinsic to human nature, which often leads to bold action by those who not know that they do not know what they do not know.
Complexity is a property of systems that exhibit intermediate levels of interdependence, connectedness, and diversity (Page, 2009). Humanity is both a part of and apart from the natural world. Humans are complex and complexity is abundant in the natural world (Page, 2012). Emergence is a result of complexity in which macroscopic properties are disjoint from the microscopic properties of a system’s elements (Miller & Page, 2007). One example is the “invisible hand” of Adam Smith (1776), a spooky-sounding description of how a complex system’s emergent behavior can seem paradoxical to an individual, as it tends “to promote an end which was not part of his intention.” The properties of a forest are not understood from the properties of a tree. The natural world, including humanity, behaves in ways that can seem unpredictable, ironic, or paradoxical. Complexity, ignorance, and hubris are known principles that conspire to produce what Tenner describes as revenge effects. Tenner’s thesis is reasonable.
Bowler & Morus (2005, pp 479-480) describe the Manhattan Project in terms that typify Tenner’s thesis both in the ironic nature of its effect and in its exchange of an acute and immediate problem for another that is deferred and chronic. The Project was a United States undertaking to develop a nuclear weapon during World War II. It was launched in response to a parallel effort believed to be underway by the German Reich with which the nation was at war. The Project succeeded, albeit after V-E Day, after which it was revealed that there was no counterpart German program. Still, the Bomb was used in 1945 to end the war in the Pacific and to frame the post-war relationship with the Soviet Union. Less than four years later, the Soviet Union possessed a nuclear weapon whose development was both spurred by the nuclear attacks on Japan and propelled by the Manhattan Project’s results, which were acquired though espionage. The nation’s effort to avoid facing a nuclear armed adversary, ironically created a nuclear armed adversary. In line with Tenner’s thesis, the Manhattan Project exchanged the acute (albeit illusory) problem of a nuclear armed Germany for the chronic problem of a nuclear armed Soviet Union, with the attendant nuclear arms race, mutual assurance of destruction, and (using Tenner’s words) the “burden of constant vigilance” demanded by four decades of global Cold War.
Tenner includes a menagerie of non-native species in his discussion of disrupted ecosystems: gypsy moths, killer bees, and fire ants; tumbleweeds, kudzu, eucalyptus, puncture vines, and Brazilian peppers; sparrows and starlings; German carp and walking catfish. Invasive pests disrupt their host ecosystems and displace native species. Some are introduced accidentally, some intentionally. Some are helped along by technology as they migrate naturally. Technology eugenically strengthens some pests as bacteria resist medication and insects resist pesticides. Tenner’s list is extensive but not exhaustive. Toads were imported to Australia in the 1930s to eat bugs in the cane fields, but did not stay there. Poison-excreting cane toads are now a hazard to humans and animals, threaten Australia’s ecology, and are of no benefit to the cane industry (Queensland, 2011). Rabbits were brought to New Zealand in the 1800s for food and hunting, and to remind new English arrivals of their old home. In their own new home, rabbits thrived and the industry they supported prospered, but they produced disastrous results on the land (Christchurch, 2021). The story of the Gulf Coast lovebug is a cautionary tale against revenge effects. The lovebug is said to have been intentionally introduced to curb the mosquito population but was ineffectual and, because lovebugs are attracted to automotive exhaust, they confine themselves close to moving cars. The lovebug is sometimes said to have been developed in a university laboratory and this would be an exemplary revenge effect except that it is not true (Leppla, 2015).
Just as it disrupts ecosystems to introduce non-native species, it can also be disruptive to suppress a species that is present. Clearing the buffalo from the Great Plans before 1880 clearly helped prepare the ground for the dust bowl of the 1930s (Lorentz, 1938).
A revenge effect is also understood to have contributed to the plague epidemic in medieval Europe. Though New York rats may now be too formidable for that city’s cats (Zhang, 2018), it is generally understood that cats eat rats and the job of a medieval housecat was to keep rats from the home. But if witches seem real, one might attribute a more diabolical role to a cat. The devastating impact of bubonic plague on 14th century Europe is often attributed to the widespread killing of cats after a decree on witchcraft by Pope Gregory IX in 1233 (Mark, 2019). It is believed that with fewer cats, there was an abundance of rats whose fleas spread the disease. Though the actual impact of Pope Gregory IX on plague transmission is contested, this would be, and is popularly understood to be, a revenge effect.
Likewise, the hygiene hypothesis (Zaccone et al., 2006) suggests another revenge effect of species suppression. The argument goes that improvements in modern hygiene have suppressed human pathogens and parasites. This suppression of harmful organisms has created a lower incidence of infection. Fewer infections have, in turn, increased the incidence of allergies and autoimmune conditions, which has been observed. The hygiene hypothesis is unproven. But,the goal of improved hygiene is to improve health and if improved hygiene does harm to health, then this would be a revenge effect.
When technology CEO Amjad Massad (2021) remarked that "the internet was supposed to be the great equalizer but paradoxically it centralized wealth and power in one geographic area", what he observed was a revenge effect. That the Internet is so pervasive makes it easy to forget how new it is. That such cynicism surrounds it today makes it difficult to remember how much optimism surrounded its introduction. Before the World Wide Web became an Information Superhighway, early enthusiasts predicted its peer-to-peer structure would improve upon the legacy hub-and-spoke model by which public information had long been distributed (D. Childs, personal communication, 1992). In 1994, an enthusiastic Vice President launched whitehouse.gov (Internet Scout, 1994) to create a regular and personal connection between the executive branch and citizenry. Less than three decades later, that communication became so regular and so personal that the President was banned from Twitter to prevent “the risk of further incitement of violence (Collins & Zadrozny, 2021).”
In 2009, the HITECH Act became law so that electronic health records could be stored on the Internet to simplify medical record-keeping and improve patient care (Brand, 2011). Complicating, rather than simplifying care, electronic health records quickly become a leading cause of physician burnout (Collier, 2017).
Nakamoto (2008) introduced an electronic cryptocurrency to empower e-commerce. It promised to bring down the high transaction fees extracted by banks and prevent currency manipulation by governments and other financial interests. It was to create inherent trust by preventing forgery and fraud while enhancing personal autonomy and privacy (Reiff, 2021). But, revenge effects appeared as cryptocurrency quickly found a role in currency speculation (Langton, 2021), fraud (United States Department of Justice, 2021), money laundering (Oberheiden, 2021), and extortion (Myre, 2021).
In 2012, the White House blog trumpeted the Internet as a powerful egalitarian force – “the Great Equalizer” (Kanevsky, 2012). In 2013, Zuckerberg wrote that “the Internet not only connects us to our friends, families and communities, but it is also the foundation of the global knowledge economy (Ortutay, 2013).” More recent headlines tell a different story. The internet has ushered in a “new gilded age” (Krugman, 2014) driven by “tech monopolies” (Fung, 2020) practicing “surveillance capitalism” (Laidler, 2019) and algorithmic “mood manipulation” (Meyer, 2014), driving and exploiting “polarization” (Barrett et al., 2021) and “tribalism” (Wheeler, 2020); generating unsustainable levels of “income inequality” and “wealth disparity” (Pearl & Stewart, 2019).
The internet has been a fount of unintended consequences, consistent with the predictions of Tenner’s thesis, though not manifest until after its publication.
In the 1990s, passenger-side airbags were widely adopted in the United States. These were intended to protect passengers from harm in the event of a major collision, but in minor collisions they had the unintended consequence of killing small children (CDC, 1998) thus creating more harm than they prevented. In contrast with the air-bag experience in which a technology was adopted in response to the harm caused by accidents, after the disaster at Fukushima in 2015, Japan quickly abandoned nuclear power technology in response to the harm caused by that accident. A subsequent study contends that this produced its own revenge effect, causing even more deaths in Japan than the Fukushima disaster caused (Manson, 2020) (Neidell et al., 2019).
The world’s worst recorded nuclear power disaster occurred in 1986, before Tenner’s book was published. The author speculated that in the future it might have the reverse revenge effect of promoting environmentalism in the former Soviet Union. In 2003, former Soviet president Mikhail Gorbachev participated in the dedication of the European Green Belt (European Greenbelt, 2017) giving evidence that this may have happened. The green belt was itself created as a reverse revenge effect of the Cold War in a region where the absence of “human disturbances along large parts of the Iron Curtain and the surrounding areas resulted in the conservation and emergence of large areas of pristine nature and a connected system of various natural habitats and landscapes (European Greenbelt, 2017).”
Tenner’s thesis is reasonable in light of known principles, is supported by additional basis case, and is supported by predictive cases from after its publication. Thus, Tenner’s thesis is valid as a description of technology’s history and a guide in developing technology’s future. However, it has limitations and caution is warranted against its overuse. Some revenge effects, like the plague rat theory, are contested. Some, like the hygiene hypothesis, are unproven. And some, like lovebug folklore, are simply untrue.
The practical application of Tenner’s thesis is imprecise. Throughout 1999, in a global display of anticipating consequences, the Y2K bug was predicted to cause large-scale infrastructure failure in which planes would fall from the sky. Through great effort and expense, the Y2K disaster was averted. There was relief on New Year’s Eve as the lights stayed on and planes stayed in the air. But hoarding in 1999 led to a reduced demand for goods in 2000, and a recession in 2001. Reflecting Tenner’s thesis, this was unintended and unexpected. But when planes really did fall from the sky, in September of that year, this was a long-anticipated outcome but had no connection to Y2K, the long-anticipated cause. Tenner’s thesis is unwieldy.
The Law of Unintended Consequences is prominent in the public consciousness. A threat of unintended consequences is often used as an argument against action, sometimes in bad faith, sometimes when positive action is called for. The argument is powerful because of a cultural bias that weighs harmful action as worse than harmful inaction. Consider the ancient maxim, primum non nocere, that admonishes against harmful action and underlies the non-maleficence principle of bioethics (Jahn, 2011). Doing harm is always unethical. Missing an opportunity to do good is not, so non-maleficence is more compelling than beneficence and this can distort the perception of potential revenge effects. Tenner’s model is like any tool or technology. It is made to be used, but must be used wisely and with restraint.