CLIMATE CALCULATIONS
In “ClimeApocalypse!” [Skeptic], Michael Shermer draws on the widely criticized work of Danish political scientist Bjørn Lomborg to conclude that climate change is not a large concern when compared with poverty and global health.

This is a false dichotomy; few global issues we face are of greater consequence to the poor and to all living creatures on the planet than climate change. Without immediate, large-scale action, global water supplies, agriculture, disease rates and extreme weather will have profound negative consequences on all of us.

RAFAEL REYES
San Mateo, Calif.

Shermer's analysis is very anthropomorphic. It takes into account only the damages and costs to humans. It also takes into account only the current population with no accounting for future ones.

JOE VIPOND
Calgary, Alberta

SHERMER REPLIES: In response to Reyes: There appears to be a general consensus among scientists that global warming is real and human-caused, but I disagree that there is as much consensus about the consequences. Given the levels of uncertainty in climate models projecting out a century, wouldn't it be prudent to save lives now with the relatively less expensive measures we are already implementing?

As for the anthropomorphism of human suffering: Vipond is correct. We should care for the survival and flourishing of all sentient beings, starting with all primates and marine mammals and then working our way across the evolutionary branches to encompass any that can feel and suffer. Our children, and the offspring of all such sentient beings, deserve to be included in the moral sphere.

PRODUCTIVITY'S PERILS
In “Will Work for Machines” [Science Agenda], the editors discuss the role technological innovations may have played in productivity and corporate profits having increased while incomes fell in the U.S. in recent decades, with job creation not keeping up with population growth.

We live in a culture that rewards corporations for cutting labor costs, which is done in ways that include replacing older workers with younger, less expensive ones; outsourcing jobs to lower-cost countries; eliminating pension plans; and, yes, displacing human jobs with machines.

We need to prioritize the well-being of people as more important than profits. We can partly do so by making profitable corporations carry a higher percentage of the national tax burden and rewarding those that employ a lot of well-paid domestic workers with a lower tax rate.

ROBERT WISE
Campbell, Calif.

The editors neglect the role that “financial engineering” has played in these trends. Over the past 35 years the idea that the only purpose of a corporation is to make money for its owners has become reentrenched in the U.S. and elsewhere. But through much of the 20th century, many corporations shared increases in productivity with their workers in the form of increased wages and benefits.

TIM BUDELL
via e-mail

EPIGENETIC INHERITANCE
In “A New Kind of Inheritance,” Michael K. Skinner discusses the possibility that epimutations (persistent changes in certain molecules that affect gene activity without altering DNA sequences) may be a source of inherited human disease. The article details research into potential examples of multigenerational epigenetic inheritance but does not mention the caveats that currently apply to many studies in this field.

Whereas the described effects of chemical exposures on mice fit one definition of epigenetics, there is no convincing evidence that the inherited phenotypes, or traits, are caused by, rather than just correlated with, alterations in epigenetic marks such as DNA methylation.

DUNCAN SPROUL
MRC Human Genetics Unit
University of Edinburgh

How might the notion of epigenetic transmission of environmentally acquired traits relate to Soviet biologist Trofim Lysenko's ideas about the inheritability of acquired characteristics?

MEL TREMPER
Berwyn Heights, Md.

SKINNER REPLIES: Regarding Sproul's comments: Epigenetic transgenerational inheritance has been shown to occur not only in rodents but also in plants, flies, worms, fishes, pigs and humans. The first step for both genetic and epigenetic mutation research is to identify the associations and reproducibility of the phenomena. That research will then move to the causal-link phase.

In response to Tremper: In the early 1800s Jean-Baptiste Lamarck proposed the theory that environmental factors promoted phenotypic changes that affect evolution, and Lysenko derived his theories from that earlier work. A number of different investigators agree that environmentally induced epigenetic transgenerational inheritance is a neo-Lamarckian concept. Clearly, neither Lamarck nor Lysenko had any concept for the molecular mechanisms involved. The new molecular (epigenetic) insights now provide a mechanism for these earlier observations.

HOW TO IMPROVE EDUCATION
As a retired educator, I was drawn to “The Science of Learning,” Barbara Kantrowitz's article on experiments conducted in “an effort to bring more rigorous science to U.S. classrooms” and their results. But I cringed at the statement that this movement began with the No Child Left Behind Act.

In the late 1950s I went to a teacher's college, where “progressive education,” then in its waning days, was propagandized, and I entered teaching in the days of the National Defense Education Act, with its science-teaching incentives. Then, over the years, came new models and curricula and related grants to education colleges.

Here's the bottom line: Place a student from a home that values education in a class with a teacher who loves his subject and enjoys teaching, and learning takes place. Everything else is window dressing.

ROBERT L. BALLANTYNE
Gilbertsville, Pa.

MATRYOSHKA MULTIVERSE?
In “The Black Hole at the Beginning of Time,” Niayesh Afshordi, Robert B. Mann and Razieh Pourhasan posit that our three-dimensional universe may have arisen from the formation of a black hole in an earlier four-dimensional universe. Shouldn't we then expect to find two-dimensional universes created by our 3-D black holes and 1-D black holes from 2-D ones? And then what?

ANDY ROBERTSON
via e-mail

MANN REPLIES: In principle, this kind of dimensional “nesting” could exist. But there is currently no empirical evidence of such universes.

ERRATUM
Because of an editing error, “Cosmic (In)Significance,” by Caleb Scharf, gave an incorrect measure for the smallest reproducing bacteria. They measure around 200 billionths of a meter.