Register for an account


Enter your name and email address below.

Your email address is used to log in and will not be shared or sold. Read our privacy policy.


Website access code

Enter your access code into the form field below.

If you are a Zinio, Nook, Kindle, Apple, or Google Play subscriber, you can enter your website access code to gain subscriber access. Your website access code is located in the upper right corner of the Table of Contents page of your digital edition.


Sign up for our email newsletter for the latest science news

Small-scale simultaneity

Regarding the June article “If an Electron Can Be in Two Places at Once, Why Can’t You?” and Sir Roger Penrose’s explanation for the lack of macroscopic quantum effects: It would seem that the absence of “quantum strangeness” on the macroscopic level is well predicted by classical quantum theory. As is demonstrated by the contrast between the wave functions of a free electron and those of a bound electron, the formation of bonds between particles doesn’t so much collapse their wave function as localize it, by making it energetically improbable that a particle will exist outside a particular well of potential. Macroscopic matter is held together by a web of such connections. Quantum effects do not immediately disappear on some scale between buckyball and Ping-Pong ball. Rather, they gradually diminish as the increasing size and interconnectedness of an object enforces relations between particles and thus localizes their probable regions of existence. No appeal to quantum gravity is required to localize the wave functions of composite matter.

Kyle Patrick

Houston, Texas

There are many different proposals for interpreting quantum mechanics and, for those who remain unsatisfied, many alternative suggestions for modifying its formalism, usually involving arbitrarily chosen parameters. My particular suggestion does not involve such an arbitrary choice but comes from a fundamental tension between the basic principles of quantum mechanics and those of standard gravitational theory (general relativity), especially the principle of equivalence. I do not say that quantum effects “immediately disappear on some scale” but that superpositions become unstable, with a decay time that can be specifically calculated. This is experimentally testable, although apparently involving technology at the cutting edge of what is currently possible. —Roger Penrose

Preparing for takeoff

For the record, the claim that dromaeosaurs “could not fly” in June’s “The Dragons of Liaoning” is false. I was the first to publish on dromaeosaurs from Liaoning having asymmetrical flight feathers on their hands, which confirmed that these dromaeosaurs had actual wings and the ability to fly. The paper describing the fossils of these flying dromaeosaurs was one of several regarding fossil birds and pterosaurs included in The Dinosaur Museum Journal, Volume 1, August 1, 2002. For the past two decades, scientists using cladistics have claimed that dromaeosaurs were nonavian ancestors of birds, representing the best examples of how ground-dwelling dinosaurs supposedly evolved into birds. This has been one of the biggest mistakes ever made in paleontology. Perpetuating this mistake does a disservice to your readership.

Stephen Czerkas

Director, the Dinosaur


Blanding, Utah

It is not so easy to make a simple correlation between asymmetrical feathers and flight. Many flightless living birds display these feathers, but they are only one small part of a multipart flight apparatus. What does Czerkas mean by flight? Is it powered flight as in birds, gliding, or even parachuting? Asymmetrical feathers may confer an aerodynamic advantage in any of these, but whether the second two are necessarily homologous to bird flight is a complex question. Where are the data (like wind-tunnel or biomechanical studies) that support his claim that these animals were winged? Czerkas’s assertion that the use of cladistics is “one of the biggest mistakes ever made in paleontology” is laughable. Cladistics is an empirical method that estimates genealogy and is used throughout systematic biology. If Czerkas understood cladistic analyses, he would realize that none of us ever said that dromaeosaurs were the ancestors of birds. Rather, the current hypothesis places dromaeosaurs and troödontids together in a group that shares a common ancestor with birds. Could some basal dromaeosaurs fly? I have an open mind, but I await data and evidence rather than simplistic wing-waving. —Mark Norell, curator of paleontology,

AmericanMuseum of Natural History

Ethical culture society

While I empathize with embryologist Doug Melton in his quest to treat the diabetes that affects his children [“Doug Melton: Crossing Boundaries,” June], his logic regarding bioethics seems flawed. He believes that most people confuse ethics with morals and that their ethics are based on their religious beliefs. I would argue that our human dignity is the precursor for ethics and that the artificial creation of living, thinking organisms must take into account the dignity of those created. If we do not take this approach, then the work of Nazi doctor Josef Mengele and those involved in the Tuskegee syphilis experiments was not intrinsically wrong but merely governed by a different view of ethics. Government regulation in a healthy democracy may minimize the potential for those with overwhelming ambitions to ignore individual dignity.

Greg R. Beaumont

Saint Paul, Minnesota

Our animals, ourselves

I was going to write a philosophical dismantling of the implausibilities in “What Do Animals Think?” [May], such as the overgeneralizing about rather different nonhuman animals, to say nothing of the oxymoronic actions of making the killing of cows more pleasant for them, but William Wegman’s ironic photographs beat me to it. Dogs’ and other mammals’ responses to and offerings of displays of affection, which are so unlike an autistic person’s relationship to other people, completely undermine the model proposed in the article for interspecies understanding. Given the fact of biological evolution, we had better find both striking similarities and dissimilarities to ourselves in our fellow creatures—otherwise, how to explain ourselves? The place to begin is with the deep similarities, and affection is one of them.

Ken W. Gatzke, professor of philosophy

Southern ConnecticutState


New Haven, Connecticut

I was very disturbed by “What Do Animals Think?” in which you claim that animal scientist Temple Grandin “has done more to improve animal welfare than almost any human alive.” What has she done to improve the lives of billions of farm animals that spend their entire existence in overcrowded buildings where they can barely move? If Grandin cares so much about animal welfare, then why is she not promoting vegetarianism?

Tiffany Yesavage

Golden, Colorado


In a caption on page 66 in June’s “Can a Single Brain Cell Recognize Bill Clinton?” we wrote that negatively charged potassium rushes out of a neuron during an action potential. Those potassium ions are positively charged.

    2 Free Articles Left

    Want it all? Get unlimited access when you subscribe.


    Already a subscriber? Register or Log In

    Want unlimited access?

    Subscribe today and save 70%


    Already a subscriber? Register or Log In