I was taken aback by Mariette DiChristina’s announcement in “Science Communication 101” [From the Editor] that she was stepping down as editor in chief and moving on to a position at Boston University.

I have been a consistent reader of Scientific American since 1963. About 10 years ago I began to notice a positive difference in the magazine: coverage of both science and world events! Finally, you were encouraging scientists to take their rightful place in the world, with coverage of topics such as women’s health and the reality of industrially caused global warming.

Most media publications have succumbed to glitzy marketing. The opposite has happened in your case. I credit much of this welcome orientation to DiChristina. I’ll probably never meet her, but I hope she continues to exercise her incredible vision in her new position and that the editors of Scientific American choose a successor who has the intelligence and vision that she has exhibited.

JON DEAK Artistic Director, Very Young Composers, New York Philharmonic


“When ‘Like’ Is a Weapon” [Science Agenda], the editors’ opinion article on the growing use of disinformation campaigns, says that journalists “must be trained in how to cover deception” and governments “should strengthen their information agencies to fight back.” What it overlooks is that, in many cases, politicians and journalists not only do not want to stop deception, they benefit from it. In this current political cycle, Donald Trump and the GOP have become masters of disinformation. Likewise, some journalists are already trained to cover deception.


The editors say, “Little is known ... about the effects of long-term exposure to disinformation.” But the American colonies and the U.S. have a 400-year history of it, including lies supporting the African slave trade, the deliberate genocide of Native Americans and the Jim Crow era of racism—as well as those about the “imminent threat” of Russia and China during the cold war and Iraq having weapons of mass destruction.

There is no need for further research. What is required is a clear-cut exposure of the liars that is just as nasty as they are.

JOHN JAROS Philadelphia

After reading the editors’ assessment, I was disappointed to go to your Web site and see articles identified as “Most Popular.” You cannot know which articles are most visited in the print magazine, so this seems to be another clickbait system where those that get the highest number of “views” are promoted. It doesn’t mean they are better written or convey better science.

JOHN DOHRMANN via e-mail


In “Virtually Reality,” George Musser refers to both the multiverse seemingly implicit in some cosmological models, which appears straightforward, and the many-worlds interpretation of quantum theory, which seems to engender difficulties.

He presents a scenario in which a photon may pass through or be reflected from a half-silvered mirror. It seems there should be a 50–50 chance of each result and two equally real worlds where each has occurred. Yet what if we prepare the mirror so that there is a two-thirds probability of the photon passing through? Are there now “A” and “B” worlds where it did so and a “C” world where it was reflected? Or are there still just two worlds, but one is somehow twice as “real” or probable?


MUSSER REPLIES: Smith has put his finger on the main conceptual problem with the many-worlds interpretation: probability. For the very reasons he gives, you can’t just count worlds; you need a more sophisticated analysis of how observers should weigh the possibilities, given that they don’t know which world they live in. California Institute of Technology cosmologist Sean Carroll has an easy-to-follow discussion regarding the quantum multiverse in his new book Something Deeply Hidden.


“Too Much of a Good Thing,” by Claudia Wallis [The Science of Health], reports on a study that links vitamin B consumption with hip fractures. This kind of correlation does not imply causation. Older people who consume large amounts of vitamin B may just be more active, which could also lead to more hip fractures.

WILLIAM QUARLES Berkeley, Calif.

WALLIS REPLIES: Good point. Epidemiological studies such as the ones I described indeed cannot prove causality. These were, however, two large, high-quality studies, and there are some plausible mechanisms to link the vitamins and fractures, which makes a connection harder to dismiss.


I am amazed there is a debate on the reality of mathematical objects, as described in “Numbers Game,” by Kelsey Houston-Edwards. At least since the days of Immanuel Kant, it has been clear we live in a reality of ideas that reside in our individual and collective mind. These ideas represent an external reality but are not that reality itself. Furthermore, most of our conscious thoughts build on our understanding of external reality and affect it through our actions. Mathematics is only as fictional as law, love, economics and government.

CLYDE OAKLEY Centennial, Colo.

Why are mathematical constructs singled out when the question of existence is applicable to every word, symbol and concept? To suggest the number one or the verb “run” are real rather than models of real things is to espouse a dualism similar to Plato’s worlds of being and becoming. The instantiations of mathematics and every field of study are discovered; the models are invented. Otherwise the current theory of physics is foundationally flawed.



In “A New World Disorder,” Claire Wardle refers to Russians hacking into e-mails from the Hillary Clinton campaign as an example of “genuine information that is shared with an intent to cause harm.”

I don’t understand the fuss about Russians’ efforts to discredit Clinton. If they didn’t falsify anything, I would have considered it a public service. Aren’t voters entitled to get as much information about the character of a candidate as possible?

FRED BUSHNELL Pfalzgrafenweiler, Germany

WARDLE REPLIES: There are a number of reasons certain information should be leaked or shared, which is why we have protections for whistle-blowers. But illegally hacking into an e-mail service to “reveal” information that should have been secured is not a characteristic of a functioning society. We have freedom-of-information laws in many countries to allow the investigation of communications and actions by people in authority. I wrote the article partly to get people to think about the complexities of this space. Sometimes it’s in our interest to have access to genuine information, but that’s why we have laws and ethical guidelines around secret recordings, hacking and whistle-blowing: the same techniques that can be used for the public good can be used by bad actors who are trying to publicize information that does not benefit the public interest.