The Dirty Truth about Plug-in Hybrids,” by Michael Moyer, failed to present an accurate and complete picture of the environmental benefits of plug-in and all-electric vehicles. The “regions” that the article cites are subject to significant ­local variation, especially for communities where increased use of these vehicles might be targeted by local planners. For example, Virginia, which is lumped in with the rest of the Southeast, actually has an electricity production profile much closer to the Mid-Atlantic. Because more than one million folks in the state live within 30 miles of the nation’s capital, increased use of all-electric vehicles would give a reduction in emissions from electrics, not an increase. But even plug-in hybrids would likely decrease local ozone levels, which has been among the most elusive of the targets of the Clean Air Act ever since the act was passed.

All-electrics also do not use oil or cool­ants. Depending on the model, they may not use brake fluid, either. All this would bring additional local and national environmental benefits.
R. Steven Brown
Executive director
Environmental Council of the States
Washington, D.C.

Is there a second “dirty truth” about plug-in cars? With a switch to electric motors, energy now delivered over the “gas station grid” would be delivered over the electric power grid instead. The increase in capacity required by such a change would not come cheaply.

Disaster preparedness and recovery also need to be considered. Before a hurricane, the power grid will have to be large enough to handle a surge as people charge up their cars in anticipation of losing power. Further, because highways often suffer less damage than power lines in a disaster, gas stations can reopen relatively quickly if they have generators to power their pumps. Plug-in cars cannot be refueled until the electric power grid is restored. Switching to electric cars means putting all our eggs in one basket instead of relying on two largely separate grids.

Although plug-in cars and hybrids may well be part of a greener future, I suspect that driving less—reining in suburban sprawl and promoting mass transit—will be key to bringing transportation-based carbon emissions under control.
Stephen J. Schnably
Coral Gables, Fla.

P. W. Singer’s “War of the Machines” reminded me of the 1967 Star Trek episode “A Taste of Armageddon.” In this show the Enterprise has encountered two planets at war, although there is no evidence of death, maiming, destruction, fire, and so on. Turns out the two planets have been waging their war by computer. The computers designate certain areas “hit,” but there is no resulting physical damage to the environment. The people in “hit” areas have to report to a “disintegration center” for voluntary suicide.

Captain Kirk’s solution is to blow up the war computers on one of the planets because, he says, “Death, destruction, disease, horror. That’s what war is all about ... that’s what makes it a thing to be avoided. You’ve made it neat and painless. So neat and painless, you’ve had no reason to stop it.... I’ve given you back the horrors of war ... you have a real war on your hands. You can either wage it with real weapons, or you might consider an alternative.... Make peace.”

Although Singer’s article does not go this far, it seems a not unreasonable step from war by robots to war by computers. A reviewer of the Star Trek episode quoted General Robert E. Lee: “It is well that war is so terrible, or we should grow too fond of it.” I am not fond of war. Would that robots would negotiate peace.
Lila Porterfield
Clarkesville, Ga.

In “No Country Is an Island” [Critical Mass], Lawrence M. Krauss describes the probable apocalyptic effects of a postulated nuclear war between India and Pakistan. After tensions escalated in the late 1990s, the two countries set up a “hotline” and various dialogues aimed at avoiding catastrophe. And despite much mutual animosity, neither India nor Pakistan denies each other the right to exist, in principle and a priori.

Yet many do not appreciate the far greater threat now looming between Israel and Iran. Israel is believed to have hundreds of warheads, with second-strike capability. Moreover, it faces explicit existential threats from Iran and other extremist entities, which are edging closer to nuclear capability. Alone of all peoples, those of Israel have faced attempted extermination in recent history and believe themselves to be under a renewed threat. There exists no logical route whereby dialogue or hotlines could be set up between two enemies in a conflict where one side refuses point-blank to recognize the other’s right to exist per se. Nor would Israel, if faced with certain genocide, have any reason not to take the rest of humanity with it to the funeral pyre.

Whereas there are many reasons to dislike Israel’s obdurate and often ham-fisted foreign policy, the wider interests of humankind are ill served by demands for Israel to be isolated or removed from the planet.
Michael Martin-Smith
Hull, England

In the Key Concepts for Alison Gopnik’s “How Babies Think,” the wording and perspective are not quite correct: “Children learn about the world much as scientists do—in effect, conducting experiments, analyzing statistics and forming theories to account for their observations.” I believe you meant to say: “Children learn about the world much as scientists do—smashing things to smith­ereens, staring in wonder at the results and then breaking out in giggles.”
Michael Jacob
Oakland, Calif.