As an undergraduate physics major in the mid-1980s at the University of California, Berkeley, I knew about Richard Muller—the physics professor who was the subject of Michael D. Lemonick’s interview, “‘I Stick to the Science’”—and his controversial theory that a “death star” was responsible for major mass extinctions. Later, as a graduate student studying climate, I became aware of Muller’s work attempting to overthrow the traditional Earth orbital theory of the ice ages—that, too, didn’t pan out. To be clear, there is nothing wrong in science with putting forth bold hypotheses that ultimately turn out to be wrong. Indeed, science thrives on novel, innovative ideas that—even if ultimately wrong—may lead researchers in productive new directions.

One might hope, however, that a scientist known for big ideas that didn’t stand the test of time might be more circumspect when it comes to his critiques of other scientists. Muller is on record accusing climate scientists at the University of East Anglia Climatic Research Unit of hiding data—a charge that was rejected in three separate investigations. In his interview, Muller even maligned my own work on the “hockey stick” reconstruction of past temperatures. He falsely claimed “the hockey-stick chart was in fact incorrect” when in fact the National Academy of Sciences affirmed our findings in a major 2006 report that Nature summarized as “Academy affirms hockey-stick graph.”  Scientific American itself recently ran an article it billed as “Novel analysis confirms climate ‘hockey stick’ graph” [“Still Hotter Than Ever,” by David Appell, News Scan; Scientific American, November 2009].

Rather than providing a platform for Muller to cast aspersions on other scientists, Lemonick could have sought some introspection from him. How, for example, have the lessons learned from his past failures influenced the approach he has taken in his more recent forays into the science of human-caused climate change? More than anything else, the interview was simply a lost opportunity. Not only can Scientific American do better, it will need to.
Michael E. Mann
Pennsylvania State University

Inside the Meat Lab,” by Jeffrey Bartholet, failed to point out one major issue. Unlike animals, the bioreactor-based meat he proposes does not have an immune system. Hence, the nutrient-rich cell-growth systems would have to be run in a completely microbe-free environment, significantly raising costs. A single contaminant could ruin tons of meat products. If the solution is to introduce antibiotics, then one has to weigh the benefits of mass-producing ethical meat against the dangers of generating antibiotic-resistant bacteria—an all too familiar dilemma.
Louis de Léséleuc
Infections and Immunity Group
National Research Council Canada

“Quotable” [Advances] took a line out of context from an editorial I wrote for the newspaper of the American College of Surgeons concerning new findings in the biochemistry of semen. Research had shown that the seminal fluid might have mood-enhancing effects on women after unprotected sex and promote stronger bonding between partners—a gift from nature. The lighthearted comment you quoted (that it may be a better Valentine’s gift than chocolate) amused most readers of the newspaper but irritated others. Despite my apologies and resignation as editor, a group of women threatened to protest at any medical meeting I attended, so I resigned as president-elect of the organization. Steven M. Platek, co-author of the semen study, commented: “How can someone be asked to resign for citing a peer-reviewed paper? Dr. Greenfield was forced to resign based on politics, not evidence. His resignation is more a reflection of the feminist and anti­-scientific attitudes of some self-righteous and indignant members of the American College of Surgeons. Science is based on evidence, not politics. In science, knowing is always preferable to not knowing.”

It also helps to know the whole story.
Lazar J. Greenfield
Professor emeritus of surgery
University of Michigan at Ann Arbor

Christof Koch and Giulio Tononi [“A Test for Consciousness”] defined an experimental method that seems likely to improve significantly on the Turing test as a way to operationally define and identify “intelligence.” The use of sensible versus nonsensical composite images would surely pose challenges to machines—today and for the foreseeable future. I think the article has two weaknesses, however. First, I think the authors underestimate the rate of progress that artificial intelligence will make in this area if it is deemed important. As they point out, the human ability to discern implausible relationships is based on a vast amount of knowledge acquired from experience. The foundations for giving machines that experience have been under development for decades and are gaining traction in many application areas today. It would be silly to take on faith that these tasks are fundamentally or nearly beyond what machines can do.

The second weakness, in my opinion, is that it confuses consciousness with integrated knowledge. Requiring machines to demonstrate that they understand visual elements and relationships seems a straightforward and appropriate aspect of intelligence. But it does not mean that any machine that exhibited that kind of perceptual and cognitive capability would obviously be conscious.

At its core, consciousness is a term we use to refer to our common human perception that we exist, are aware of ourselves and are aware of our being part of the environment with which we are interacting. Self-awareness and awareness of self versus our environment would seem to be important attributes of consciousness, regardless of how it might ultimately be defined and identified. The authors’ proposed test neither depends on those attributes nor distinguishes those having them from those lacking them.
Rick Hayes-Roth
Professor of information systems
Naval Postgraduate School

In “Living in a Quantum World,” Vlatko Vedral insists that “quantum mechanics is not just about teeny particles. It applies to things of all sizes: birds, plants, maybe even people.” But all his examples of entanglement refer to the teeny particles—atoms and molecules. The fact that, in some examples, the entangled particles are located within organisms—birds, plants—does not prove that these organisms themselves are entangled. Do the particles and the bodies behave according to the laws of quantum mechanics? Vedral’s answer is affirmative. But that something appears that way to the author and his colleagues is not a sufficient base for sweeping generalizations. 
Alexander Yabrov
Princeton, N.J.