Alec Nevala-Lee

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Archive for March 29th, 2018

The dreamlife of engineers

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In 1985, the physicist Freeman J. Dyson delivered a lecture at the semiconductor company Analog Devices in Norwood, Massachusetts, which later became a chapter in his book Infinite in All Directions. He opened the talk, which he called “Engineers’ Dreams,” with these words:

There are two ways to predict the progress of technology. One way is economic forecasting, the other way is science fiction. Economic forecasting makes predictions by extrapolating curves of growth from the past into the future. Science fiction makes a wild guess and leaves the judgment of its plausibility to the reader…For the future beyond ten years ahead, science fiction is a more useful guide than forecasting. But science fiction does not pretend to predict. It tells us only what might happen, not what will happen. It deals in possibilities, not in probabilities. And the most important developments of the future are usually missed both by the forecasters and by the fiction writers. Economic forecasting misses the real future because it has too short a range; fiction misses the future because it has too little imagination.

Dyson took the title of the talk from a book by the science writer and rocket scientist Willy Ley, of which he said wistfully: “The dreams which are recorded in his book are mostly projects of civil engineering, enormous dams, tunnels, bridges, artificial lakes and artificial islands. The interesting thing about them is that they are today totally dead. Nobody would want to build them today even if we could afford it. They are too grandiose, too inflexible, too slow…History passed these dreams by. We do not any longer find it reasonable to think of flooding half of the forests of Zaire in order to provide water for irrigating the deserts of Chad.”

Engineers’ Dreams was one of Dyson’s favorite books, and it pops up elsewhere in his writings. (Notably, it figures prominently in his essay “The Search for Extraterrestrial Technology,” in which he lays out the logic behind the ultimate engineering project—the Dyson Sphere.) As an example of how even a genius can fail to foresee how the history of technology will unfold, he told a story about the mathematician John von Neumann, whom he fondly described as perhaps “the cleverest man in the world.” Speaking of a talk that von Neumman delivered in the early fifties, Dyson said:

Meteorology was the big thing on his horizon…He said, as soon as we have some large computers working, the problems of meteorology will be solved. All processes that are stable we shall predict. All processes that are unstable we shall control. He imagined that we needed only to identify the points in space and time at which unstable processes originated, and then a few airplanes carrying smoke generators could fly to those points and introduce the appropriate small disturbances to make the unstable processes flip into the desired directions. A central committee of computer experts and meteorologists would tell the airplanes where to go in order to make sure that no rain would fall on the Fourth of July picnic. This was John von Neumann’s dream.

“Why was Von Neumann’s dream such a total failure?” Dyson asked. “The dream was based on a fundamental misunderstanding of the nature of fluid motions…A chaotic motion is generally neither predictable nor controllable…Von Neumann’s mistake was to imagine that every unstable motion could be nudged into a stable motion by small pushes and pulls applied at the right places. The same mistake is still frequently made by economists and social planners, not to mention Marxist historians.”

Von Neumann’s other mistake, Dyson added, was to think of computers in the future as expensive and rare, rather than cheap and widely available, and to underestimate how technology tends to move away from “big and sluggish” applications. Thirty years later, however, we seem to be talking more urgently about such grandiose projects than ever, at least when it comes to the problem of climate change. Whatever their real merits, such measures as fertilizing the oceans with iron, releasing sulfur dioxide into the atmosphere, converting carbon dioxide on a large scale into limestone, or building a solar farm the size of Nigeria would undoubtedly be massive acts of engineering. As Elizabeth Kolbert recently wrote in The New Yorker:

Everyone I spoke with, including the most fervent advocates for carbon removal, stressed the huge challenges of the work, some of them technological, others political and economic. Done on a scale significant enough to make a difference, direct air capture of the sort pursued by Carbon Engineering, in British Columbia, would require an enormous infrastructure, as well as huge supplies of power.

Kolbert quotes the physicist Klaus Lackner, the founder of the Center for Negative Carbon Emissions, who wondered why “nobody’s doing these really crazy, big things anymore.” But we’re certainly discussing them today. And one of the most prominent advocates of such measures is Dyson himself, who wrote in the late seventies—before it was fashionable—that atmospheric carbon levels could be controlled by planting a trillion trees. (He later proposed the genetic engineering of special “carbon-eating trees,” of which he conceded: “I suppose it sounds like science fiction.”)

On some level, it’s ridiculous that we’re even contemplating such projects, as David Keith, the founder of the firm Carbon Engineering, observed to Kolbert: “You might say it’s against my self-interest to say it, but I think that, in the near term, talking about carbon removal is silly. Because it almost certainly is cheaper to cut emissions now than to do large-scale carbon removal.” But when it comes to “chaotic motions” of the kind that frustrated von Neumann, politics is worse than the weather, and we’re rapidly reaching a point—if we aren’t there already—when planting billions of carbon-eating trees seems more feasible than changing the minds of a few million voters, or even one hundred elected officials. As Kolbert writes:

One of the peculiarities of climate discussions is that the strongest argument for any given strategy is usually based on the hopelessness of the alternatives: this approach must work, because clearly the others aren’t going to…As a technology of last resort, carbon removal is, almost by its nature, paradoxical. It has become vital without necessarily being viable. It may be impossible to manage and it may also be impossible to manage without.

In his talk, Dyson noted that the “qualitative changes” that emerge from the actions of individuals are what make the future so hard to predict: “Qualitative changes are produced by human cleverness, the invention of pocket calculators destroying the market for slide rules, or by human stupidity, the mistakes of a few people at Three Mile Island destroying the market for nuclear power stations.” From an engineer’s point of view, any solution that depends on the rational persuasion of politicians or entire societies is necessarily vulnerable to failure, so it might be better to avoid the problem entirely. I don’t want to believe this, but we may not have a choice. As Dyson concluded three decades ago: “Neither cleverness nor stupidity is predictable.”

Quote of the Day

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I’ll use dirty tricks [in coding] for two reasons. One is if it’s really going to give me a performance improvement and my application is one that the performance improvement is going to be appreciated. Or sometimes I’ll say, “This is tricky; I couldn’t resist being tricky today because it’s so cute.” So just for pure pleasure. In any case, I document it; I don’t just put it in there.

Donald Knuth, to Peter Seibel in Coders at Work

Written by nevalalee

March 29, 2018 at 7:30 am

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