Discover more from Energy Talking Points by Alex Epstein
How the establishment uses the “straw man” fallacy and the “soft man” fallacy to dismiss powerful challenges — the case of Tyler Cowen and Fossil Future
Upon learning that I considered his recent comments on my book Fossil Future to be a severe distortion of the book’s conclusion and arguments, prominent economist Tyler Cowen offered to feature my objections on his popular blog Marginal Revolution. (Welcome, Marginal Revolution readers! If you’d like to subscribe to this free Energy Talking Points newsletter, just click below.)
I took him up on this opportunity for 2 reasons:
First, I would like to give Marginal Revolution readers (and other new readers) the opportunity to consider Fossil Future’s actual conclusion and arguments, vs. what I regard as their misportrayal in Tyler’s comments.
Second, I think Tyler’s comments involve the use of two fallacies that, together, are often used to dismiss powerful challenges to dangerous establishment ideas:
“Strawmanning” powerful new ideas to make them appear unreasonable.
“Softmanning” the challenged establishment ideas to make them appear reasonable.
I hope that seeing these fallacies illustrated in detail will help readers spot them in other contexts.
Tyler Cowen’s strawmanning of the energy/climate policy advocated by Fossil Future
Tyler’s comments on Fossil Future portray the book as advocating endless, multi-century growth in fossil fuel use and CO2 emissions. Specifically, he uses the formulations “keep on producing increasing amounts of emissions for centuries on end” and “keep on boosting carbon emissions without end” to capture what the book is arguing (in contrast to his view).
But Fossil Future does not advocate anything of the sort.
Fossil Future argues for increasing fossil fuel use over the next several decades. It does not specify what should happen to fossil fuel use after that but instead 1) provides guiding principles deciding on pro-human policies toward fossil fuel use, and 2) advocates policies in the meantime to maximize the growth of cost-effective alternatives to fossil fuels.
Allow me to elaborate and illustrate with extensive quotations from Fossil Future, since most readers of Marginal Revolution (and many other readers of this piece) have not read the book and will understandably be skeptical of my claim that Tyler has severely misrepresented it.
The primary subject matter of Fossil Future is: What should happen to fossil fuel use over the next several (2-4) decades?
It focuses on this time period because it’s the time period that today's energy/climate policies are overwhelmingly aimed at.
Fossil Future's position about the next several decades is: if we carefully weigh the relative benefits and side-effects of continuing fossil fuel use by the standard of “global human flourishing”—in a world where far more energy is needed as quickly as possible—we need more overall fossil fuel use, not less.
Fossil Future is very clear about the timetable it is focusing on. Criticizing the mainstream position, it uses some variant of “rapidly eliminate fossil fuel use” 56 times. In advocating its own position, Fossil Future uses some variant of “continuing fossil fuel use” 47 times, designed to capture the near future, vs. 100 years in the future, let alone the “centuries on end” Tyler refers to. The book repeatedly refers to a several-decade timeline. For example, in considering the viability of alternatives to fossil fuels it says “our extremely strong baseline expectation over the next thirty years should be...” [page 204]
As one commenter on Tyler’s article put it—one of the few that was not misled, having already read Fossil Future—“Alex's book is clearly focused on the next several decades as are all of the politicians and their destructive policies claiming that we need to eliminate fossil fuels rapidly. 95% of your response to his book is irrelevant.”
About the more distant future—multiple generations from now—Fossil Future does not, contrary to Tyler’s portrayal, advocate for “carbon emissions without end.” It actually does not offer any specific predictions or prescriptions because there are too many uncertainties about the future state of energy economics, the future state of climate, and the future state of our ability to master climate.
Instead, it offers principles, specifically:
1. Principled guidance on how to make decisions about energy/climate policy given the state of economics and science at a given time.
Fossil Future on the crucial principle to evaluate what to do about rising CO2 or any other side-effect of fossil fuels: “the freedom from endangerment,”
If a side-effect is not a demonstrable and significant harm, it does not violate the freedom from endangerment. But even if a side-effect is a demonstrable and significant harm, it only violates the freedom from endangerment if it meets the criterion of being “reasonably preventable.” “Reasonably preventable” means that something can be prevented without doing greater damage for most or all people.
What side-effects are considered reasonably preventable will depend on the danger of the side-effect and the state of our ability to produce energy without that side-effect.
If governments do their job in classifying side-effects as endangerment only when they are reasonably preventable, they achieve two great results: the liberation and therefore growth of energy production and the progressive reduction of pollution and danger. [pages 387 - 388]
Fossil Future on how to think about fossil fuels' benefits vs. its climate side-effects at any given time:
two questions of this part of the book: How powerful is fossil-fueled climate mastery at dealing with the kinds of climate dangers we’re worried about—such as extreme temperatures, droughts, wildfires, storms, and floods?….What are the likely impacts of rising CO2 levels—negative, neutral, and positive—on our naturally dangerous, diverse, and dynamic climate system? [page 258]
Fossil Future on options if the most extreme global warming projections come true over the next century:
if we decriminalized non-carbon nuclear energy, we would have plenty of time to develop the potential of that technology for all types of machines. And that’s leaving aside global climate-cooling technology, which is almost certainly masterable over the next hundred years. So even an extreme amplified greenhouse effect, with a climate CO2 sensitivity of 5°C, would be masterable temperature-wise. [page 232]
Reading Tyler’s portrayal of Fossil Future as advocating “increasing amounts of emissions for centuries on end” you would never imagine that it gives nuanced and novel principles for thinking about at what point in the future emissions should decrease.
2. Principled guidance on how to liberate alternatives to fossil fuels today so that they can cost-effectively proliferate as quickly as possible.
You would certainly never imagine from Tyler’s portrayal that Fossil Future offers a promising path to develop genuine long-term replacements for fossil fuels. But yet the book undeniably does this.
Fossil Future on the value of developing cost-effective alternatives:
It’s crucial to identify how to liberate the use of fossil fuels while also fostering the ability of alternatives like nuclear to substitute where it makes sense today and to develop, if possible, into superior replacements in coming generations. [page 361]
Fossil Future on the imperative to “decriminalize nuclear”:
The key to decriminalizing nuclear is to have consistent safety standards across all forms of energy. It makes no sense to hold nuclear to thousands of times the safety standards of hydro or natural gas.
Safety standards must be based on the principles of “demonstrably and significantly harmful” and “reasonably preventable.” That means scrapping LNT (“linear no-threshold”) as well as ALARA (“as low as reasonably achievable”—which in practice is incredibly unreasonable, leading to unreasonably high costs that cause us to use far more dangerous nonnuclear energy).
If nuclear safety standards were based on these principles, we’d likely see unbelievable innovation as smart people all over the world were finally free to unleash the human flourishing potential of the atom. [page 390]
Fossil Future on the “freedom to develop,” which is crucial to liberating all energy potential, including “ultradeep geothermal”:
Human beings can only engage in cost-effective energy production and therefore modern productivity to the extent they are free to engage in the development that energy production requires. If and to the extent the freedom to develop doesn’t exist, energy cannot be produced cost-effectively or at all. [page 369]
As with solar, wind, and biomass, if geothermal managed to become ultra-cost-effective at some point, it would surely attract opposition from our anti-energy knowledge system due to the inevitably large impact on nature it would have. For example, advanced geothermal, like much oil and gas drilling, makes use of fracking in order to crack rocks and release heat. Does anyone believe that Greenpeace and the Sierra Club wouldn’t come after geothermal fracking if it were widespread? Is there any chance that anti-impact hostility won’t increase if deep geothermal projects are known to be drilling over ten thousand feet below the surface of the earth? [page 231]
Fossil Future on how grids can ensure the most cost-effective options, including alternatives to fossil fuels, win out:
In the context of the electrical grid, choices should be made by some form of what I call “long-term system-cost analysis.” This means looking at the full costs of different options in the long term, given the likely needs of electricity users, and then choosing the best options. [page 379]
Given that Fossil Future 1) argues for increasing fossil fuel use over the next several decades, not centuries, 2) provides principles for deciding on pro-human energy/climate policies in the future, and 3) advocates policies in the meantime to maximize the growth of cost-effective alternatives to fossil fuels, you would expect Tyler’s critical comments to address and refute one or more of these arguments.
Instead, he 1) bizarrely portrays Fossil Future’s position as “keep on boosting carbon emissions without end,” and treats (2) and (3) as nonexistent even though they are crucial to the book’s argument.
This is a clearcut example of the “straw man” fallacy: trying to discredit an argument by significantly misrepresenting it, then attacking one’s own misrepresentation.
Tyler Cowen’s “softmanning” of the energy/climate policy advocated by the mainstream
While Tyler severely distorts Fossil Future’s position in a negative way (strawmanning), he also distorts the mainstream view Fossil Future is arguing against, but in a positive way.
The mainstream position on this issue, which is Fossil Future's main target of criticism, is clear: over the next several decades the world should rapidly eliminate fossil fuel use, specifically reaching “net zero” CO2 emissions by 2050. As summarized and demonstrated in Fossil Future:
trusted source after trusted source tells us: that experts, especially climate scientists, have reached a near-unanimous consensus that fossil fuel use needs to be rapidly eliminated. [Page 5]
Catastrophic climate change, along with other negative side-effects of fossil fuel use, such as air pollution and water pollution, make us morally obligated to rapidly eliminate fossil fuel use and reach “net-zero” CO2 emissions by 2050 at the latest—so as to limit warming to 1.5°C, or at the absolute most 2°C, over preindustrial, pre–fossil fuel temperatures. [page 5]
Around the world, with few exceptions, governments are committing to eliminating the use of fossil fuels over the next several decades. In my country, President Joe Biden has made it a goal for the U.S. to have “net-zero” CO2 emissions from electricity by 2035 and from all forms of energy by 2050 [page 394]
Fossil fuel elimination is not something that the Biden administration is unique in pursuing. In fact, the U.S. is one of the last of nearly two hundred nations to sign the Paris Agreement, which commits these countries to a 0.5–1°C limit on global warming from today (1.5–2°C from preindustrial times), effectively a “net-zero” commitment. [page 394]
Fossil Future argues that mainstream position both systematically underestimates the enormous benefits of continuing fossil fuel use and systematically “catastrophizes” the negative climate-side-effects of fossil fuels. (It ultimately attributes these errors to false, anti-human philosophical ideas. [Chapter 3])
It concludes that the current anti-fossil-fuel movement’s advocacy of rapidly eliminating fossil fuel use over several decades would, if successful, be apocalyptically destructive, and therefore urgently needs to be rejected. Further, it argues (prophetically, given today’s energy crisis) that more modest attempts at elimination, which are more likely given the willingness of China, India, and Russia to increase fossil fuel use so long as it is the most cost-effective option, will be destructive.
some countries will see the cost of energy skyrocket, and with it the cost of everything else. Domestic companies will become less competitive, jobs will become scarcer, and incomes will decline. Economic collapse will become a real possibility. At the same time, electrical grids will become less reliable thanks to increasing amounts of unreliable electricity backed up by drastically decreasing amounts of reliable electricity. [page 397]
Instead of engaging with Fossil Future’s arguments against the mainstream view, Tyler criticizes it for targeting that view. For example, he criticizes me for selecting “very weak” experts to counter, such as John Holdren (former chief science advisor to President Obama), Amory Lovins (arguably the most influential energy thinker of the last 50 years), and Bill McKibben (one of the biggest influencers of environmental policies). But what Tyler calls “very weak” experts are, as I explain at length in the book, chosen because they are “designated experts”—those who are treated by mainstream knowledge institutions as spokespeople for all experts.
“Designated experts are individuals and sometimes institutions, often but not always researchers in a particular field by background, whom a knowledge system designates and prominently features as public spokespeople for the best expert knowledge and evaluation on some issue. Designated experts are frequently quoted and consulted because they are considered the people who have synthesized the best research and can both explain it clearly to us (dissemination) and help us decide what to do with it (evaluation). [page 29]
How does Tyler justify criticizing Fossil Future for engaging the mainstream view on fossil fuels and climate?
By distorting what the mainstream view is. Tyler calls advocates of the mainstream, “net zero by 2050,” view “the unrealistic ones”—conveying that they are only held by a marginalized minority of people (including the aforementioned “very weak” experts). And he portrays the mainstream view as supporting “some trajectory where—at a pace we can debate—carbon emissions end up declining,” with the “pace we can debate” extending “centuries.”
But the mainstream discussion of fossil fuels does not remotely involve “a pace we can debate.” It involves established international agreements that have decided on exactly the pace Fossil Future criticizes: net-zero CO2 emissions, or very close to it, by 2050. No mainstream institutions are saying “net-zero by 2250” (which Fossil Future argues is entirely possible if we decriminalize nuclear energy).
In misportraying the mainstream anti-fossil-fuel viewpoint as “some trajectory where...carbon emissions end up declining,” Tyler describes himself as “steelmanning” the position.
But “steelmanning” is making the best arguments for a particular position. (To see some examples of how Fossil Future does this, see Bryan Caplan’s article “Alex Epstein’s Steelmen.”) What Tyler is doing should be called “softmanning”: pretending that a particular position is much less bold (“softer”) than it actually is.
The most charitable interpretation of Tyler’s softmanning of the mainstream position is that he personally would prefer that Fossil Future address the softmanned position of “some trajectory where—at a pace we can debate—carbon emissions end up declining.”
One obvious problem here is that Fossil Future is in favor of “some trajectory” of emissions declining given its advocacy of developing long-term superior replacements for fossil fuels.
But let’s be even more charitable and say that what Tyler wanted was for Fossil Future to focus on more “moderate,” anti-fossil-fuel positions that I disagree with—e.g., reducing-but-not-eliminating fossil fuel use over the next several decades via escalating carbon taxes.
My answer: I didn’t focus on the non-mainstream anti-fossil-fuel position because the mainstream position is much more powerful and dangerous—but I did address, in detail, my disagreements with the non-mainstream position.
Fossil Future is a book that is trying to counter what I regard as a catastrophically dangerous mainstream anti-fossil-fuel movement. To focus my criticisms on a “moderate” minority of less influential thinkers, while setting aside the mainstream position—which is already implemented in international agreements and national laws—would be to softman that position and thereby fail to alert readers to its dangers.
Nevertheless, Fossil Future’s systematic breakdown of every issue related to evaluating the continuing use of fossil fuels contains counter after counter of mistakes involved in the “moderate” anti-fossil-fuel positions.
To take a just a few of many examples:
Chapter 3 explains the failure of almost every thinker to be clear on their “standard of evaluation,” and instead combine the incompatible goals of “eliminating human impact” (anti-human) with “advancing human flourishing” (pro-human). [pages 74 - 82]
Chapter 4 explains that almost every thinker fails to appreciate the full benefits of cost-effective energy in general and fossil fuel energy in particular, citing example after example that most thinkers fail to take into account. Contrary to Tyler’s portrayal of an intellectual world with some “‘unrealistic ones,’ who don’t see the benefits of fossil fuels,” Fossil Future argues that almost no one fully understands the benefits of fossil fuels. [pages 109 - 173]
In particular, Chapter 4 contains a new and substantially original section called “Our Knowledge System’s Pseudoscientific Benefit Denial via ‘Studies’ and ‘Externality’ Calculations” that is specifically directed at more academic errors. [pages 169 - 173] (This section and many other illustrate the inaccuracy of Tyler’s broad criticism that “In economic language, you could say he is not considering enough of the margins.”)
In the end, the most charitable interpretation of Tyler’s softmanning of the mainstream anti-fossil-fuel position—that he would personally want me to steelman a much more marginal, “moderate” position—is just another instance of Tyler strawmanning Fossil Future, since Fossil Future substantively steelmans every element of the “moderate” anti-fossil-fuel position and Tyler’s comments portray it as not engaging this position at all.
The destructive consequences of “strawmanning” new ideas and “softmanning” the establishment
In general, and with Tyler’s treatment of Fossil Future in particular, the dual-practice of strawmanning a challenge to a mainstream position while softmanning the mainstream position itself has at least 2 highly destructive consequences.
It causes important new ideas to be dismissed without serious consideration.
It causes destructive mainstream movements to remain unchallenged.
How strawmanning causes important new ideas to be dismissed without serious consideration
When influential, credible individuals like Tyler Cowen strawman important new ideas—such as portraying Fossil Future’s careful argument for expanding fossil fuel use as “boosting carbon emissions without end”—countless people will conclude, at best, “nothing to see here.”
This certainly applies to Tyler himself who, once strawmanning Fossil Future’s basic position, proceeds to distort and/or dismiss crucial sections of the book.
Take the question of potential replacements for fossil fuels in the coming decades. Fossil Future provides a careful argument on this issue, arguing that given the need for far more energy, replacing a significant quantity of today’s fossil fuel use over the next several decades would require a truly unprecedented economic breakthrough that we have no evidence of.
Instead of engaging this argument, here’s what Tyler says (followed by my comments):
I think he is also too pessimistic about the long-run and even medium-run futures of alternative energy sources.
He does not specify Fossil Future’s views, which are actually very long-term optimistic about nuclear in particular provided we “decriminalize” it. [pages 234 - 237, 332]
More generally, I don’t think a few book chapters—by anyone with any point of view—can really settle that.
This is just an empty dismissal.
I find the market data on green investments more convincing than his more abstract arguments (yes, I know a lot of those investments are driven by subsidies and regulation, but there is genuine change afoot).
Fossil Future engages this “market data” extensively; Tyler’s comments lead readers to think that it doesn’t. [pages 210 - 223]
Even more distortions and dismissals are involved in Tyler’s treatment of the climate portions of Fossil Future. Fossil Future has 3 chapters (7-9) dedicated to the “climate side-effects” of fossil fuel use, which argue carefully that:
The “climate mastery” benefits of continuing fossil fuel use are enormous yet largely ignored by mainstream thinkers. [Chapter 7]
There are various distortions of mainstream climate research that mislead the public about the actual state of climate science. [Chapter 8]
If you factor in the climate mastery benefits of continuing fossil fuel use and the actual range of projections made by credible people on climate science, there is no case for global climate catastrophe, let alone apocalypse, and certainly no case for rapidly eliminating fossil fuel use. [Chapter 9]
Yet Tyler’s treatment of these chapters does not remotely indicate their content, often distorts their content, and includes frequent empty dismissals that are fitting for an argument that has already been discredited via strawmanning.
In a number of places, such as pp.251-252, and most significantly chapter nine, Epstein denies the likelihood of climate apocalypse,
As Fossil Future explains, the mainstream scientific accounts don’t actually involve apocalypse. [pages 330 - 332]
but I just don’t see that he has much of a counter to the standard, more quantitative accounts.
An empty dismissal of 3 chapters of novel, powerful arguments about factors omitted and distorted by “standard” accounts.
He should try to publish his more optimistic take using actual models
Fossil Future’s policy analysis considers even extreme projections by “actual models.” [pages 232 - 234]
, and see if it can survive peer review. Why should I be convinced in the meantime?
Another empty dismissal. Fossil Future gives very clear arguments about errors that many mainstream projections of the overall impact of fossil fuel use, including its climate impacts, commonly make. But after strawmanning the book, Tyler does not feel compelled to acknowledge these arguments’ existence, let alone address them.
I found chapter nine the weakest part of the book. Maybe he feels he wouldn’t get a fair knock by trying to publish his alternative take through “the standard process,” but as it stands his casual take
“Casual take” is just an insult, and a staggeringly inaccurate one.
doesn’t come close to overturning what I consider to be the most rational, consensus-based Bayesian estimate of the consequences of making no transition to green energy
Fossil Future doesn’t advocate “making no transition to green energy” on the multi-century timetable Tyler discusses. And is Fossil Future right or wrong about the errors it attributes to many evaluations of our “fossil future”? Saying “doesn’t come close to overturning” without explanation is just another empty dismissal.
Nor is there, for my taste, enough discussion of how much climate risk we should be willing to take on.
This gives no indication of Fossil Future’s extensive, nuanced discussion of what’s involved in climate risk—including its extensive unique material on “fossil-fueled climate mastery.” [pages 336 - 348]
It is not just about “beliefs most likely to be true.”
“Beliefs most likely to be true” is an insult that doesn’t remotely reflect the content of Fossil Future.
Note that the less you believe in climate models, the more you should be worried about tail risk.
Fossil Future doesn’t disbelieve in climate models; it discusses their limitations and then argues that even the extreme model projections don’t justify the mainstream policy position.
In these matters, do not assume that uncertainty is the friend of inaction.
Fossil Future has no such assumption. It seems like Tyler is just repeating a favorite talking point of his here to counter people who question climate catastrophe claims.
By strawmanning Fossil Future’s conclusion and its arguments, Tyler at best misled countless people into thinking that Fossil Future has nothing new or interesting to offer them, and at worst misled countless people into having a totally distorted view of what Fossil Future argues. Even more so because of his conclusion “I fear the final message of the work will lower rather than raise social welfare.”
How softmanning causes destructive mainstream movements to remain unchallenged
While strawmanning important new ideas causes people to think “Nothing to see here,” softmanning destructive establishment ideas causes people to think “Nothing to worry about here.”
With today’s anti-fossil-fuel movement, which calls for rapidly eliminating fossil fuel use in a world that needs far more energy, the world needs to be very worried—and it needs smart, influential intellectuals to warn them.
I believe that Fossil Future makes this plenty clear, but the global energy crisis should make it even clearer. The essential cause of this crisis is that the anti-fossil-fuel movement artificially restricted the supply of fossil fuels, on the false promise that unreliable solar and wind could replace a lot of fossil fuel use. Artificially restricted supply made fossil fuel prices artificially high before Russia’s Ukraine invasion and prevented the free world from quickly increasing production in response.
And the anti-fossil-fuel policies that caused today’s global energy crisis have been nowhere near aggressive enough according to the mainstream “net zero by 2050” position.
Softmanning these policies reassures the world when the world needs to be very, very alarmed.
Why it’s common for the establishment to use softmanning and strawmanning together to dismiss powerful challenges
While it’s hard to identify the motive for any particular instances of using strawmanning and softmanning to dismiss a powerful challenge to the establishment, there are two status-related incentives that are often operative: fear of being proven wrong and fear of being marginalized.
Fear of being proven wrong is often operative because if one is basically aligned with the establishment on some issue, a powerful new idea that challenges the establishment, if true, means that one has been significantly and publicly in the wrong—likely for a long time. Strawmanning a powerful new idea is the easiest way of dispensing with it. This often takes the form, not of explicit intent, but rather of doing a biased skimming of a work, looking for things to use to write off the book instead of truly trying to understand the book’s new arguments.
Fear of being marginalized is often operative because if one agrees with a powerful challenge to the establishment, one is in the position of being morally obligated to criticize the establishment position—something which, especially in the case of fossil fuels and climate, can carry with it a host of negative professional consequences. For example, if establishment-friendly commentators join me in condemning the “net zero by 2050 movement” as a mortal threat to humanity’s future, they will incur a lot of ire and quite possibly lose a lot of status. But if they softman Fossil Future’s powerful exposé of the establishment’s “net zero by 2050” position, and instead treat the position as merely some emissions reduction over some extended timetable, they avoid the career-threatening ire of the energy/climate establishment.
The use of strawmanning/softmanning to dismiss powerful new challenges to the establishment is extremely common. In the field of energy/climate, this tactic has been used not just against Fossil Future (repeatedly) but also against the important books Unsettled by Steve Koonin and Apocalypse Never by Michael Shellenberger. (Here is an excellent exposé on the strawmanning of Koonin.) And I am sure many readers will recognize the use of strawmanning/softmanning in their own fields, as well.
The incentives for strawmanning and softmanning powerful challenges to dangerous establishment ideas are potent—but our future depends on intellectuals having the intellectual honesty and courage not to succumb to those incentives.
When the establishment is very wrong about something, we need to welcome new ideas, not strawman them, and be willing to criticize the existing ideas—not softman them. We can see the negative consequences of softmanning the mainstream anti-fossil-fuel movement in the fact that many academics, including climate scientists, who disagree with “net zero by 2050” do not speak up prominently about it. If they did, today's disastrous mainstream position wouldn't be the mainstream position.
I have tried to do my part on energy/climate policy by writing a book that systematically refutes the mainstream call for rapid elimination of fossil fuels and puts forward a rational, pro-human policy of increasing fossil fuel use in the near-term and liberating alternatives to maximize their chances at long-term success.
I was saddened that Tyler strawmanned Fossil Future and softmanned the mainstream anti-fossil-fuel movement. I am glad he is sharing my perspective with his readers, and I hope that this piece motivates him and many others 1) to truly read Fossil Future and 2) to truly state their opinion about the dangerous movement to rapidly eliminate fossil fuels.
EnergyTalkingPoints.com: Hundreds of concise, powerful, well-referenced talking points on energy, environmental, and climate issues.
“Energy Talking Points by Alex Epstein” is my free Substack newsletter designed to give as many people as possible access to concise, powerful, well-referenced talking points on the latest energy, environmental, and climate issues from a pro-human, pro-energy perspective.