In “A Man-made Contagion,” by Jeneen Interlandi [Advances], Michael T. Osterholm of the National Science Advisory Board for Biosecurity argues, regarding studies creating mutations that would allow the H5N1 virus to readily spread between humans, that “physicists have been doing ... classified work for 70 years. We have to find a way to do the same in the health sciences, without compromising our safety and security.”

Classified physics work has put the future of our species in question, so not “compromising our safety and security” would require more stringent controls in the health sciences than were applied in the physical ones. Additionally, new life-forms can be created in an inexpensive lab with commercially available ingredients. Nuclear weapons materials are more difficult to obtain.
Martin Hellman
Professor Emeritus, Electrical Engineering
Stanford University

It would be best to destroy the existing mutated virus and place the information on creating it under the same kind of security as hydrogen bomb instructions. Freedom of information groups do not argue that thermonuclear weapons information be released to all; it is beyond foolishness to argue that infinitely more dangerous biological warfare information be made public.  

Previously in biology, the benefits of publicly shared knowledge outweighed the dangers. This is no longer always the case. We have changed the terrain here, and our mind-set must change, too.
David Green
Brooklyn, N.Y.

Is Space Digital?” by Michael Moyer, describes a proposed experiment by Craig Hogan of Fermilab near Batavia, Ill., that claims to test the holographic principle. The article quotes both of us, as theorists who played a central role in the discovery and general formulation of the holographic principle. But it fails to mention that we believe that Hogan’s experiment does not actually test this principle.

The holographic principle asserts a fundamental relation between quantum information and the areas of spacetime’s surfaces. Observation already supports it: no object in the universe is known to violate this relation. In fact, it could be ruled out by experiment: for example, if novel forms of matter were discovered that permitted violations of the holographic bound on information storage.

The principle, however, does not predict the quantum “jitters” that Hogan’s experiment seeks to detect; it predicts their absence. They would conflict with Einstein’s principle of relativity, which is central to the formulation of the holographic principle (and to our understanding of countless previous experimental results).

The holographic framework does make distinctive predictions. For an experiment occupying a region of space of about a meter in radius, it predicts subtle correlations that involve approximately 1070 photons. That is just about enough energy to make a black hole as big as the entire experiment. The length of time that it would take to accumulate the required information from the black hole would be around a quadrillion quadrillion qua­drillion times the age of the universe.

The same is true for a larger or smaller experiment: the distinctive features of the principle always involve enough photons to create a black hole as big as the experiment and an extraordinary length of time to collect the required information. Hogan’s experiment is absurdly far from this regime.
Raphael Bousso
University of California, Berkeley
Leonard Susskind
Stanford University

Marc B. Garnick’s fine article on prostate cancer [“The Great Prostate Cancer Debate”] neglects one very important consideration in its support of reduced screening: death from untreated cancer, though low, is quite often slow and very painful. I would much rather die of just about anything else.

In addition, treatment of advanced prostate cancer is no cakewalk. My prostate cancer was removed surgically after it was diagnosed, but my brother’s was too far advanced. He is now being treated by hormones and other drugs, and his life is far from rosy: weight gain, hot flashes, heart problems and incontinence are not his only problems. For me, the prostate-specific antigen (PSA) test was a godsend.
Joe Cusack
Scottsdale, Ariz.

The discussion should not be about the many low-grade tumors that elevated PSA tests find but about how many mid- and high-grade tumors are discovered. The fact that elevated PSA scores can indicate the possibility of aggressive cancers in the prostate sooner than any other noninvasive test should justify some per­iodic PSA testing for men. How often these screenings should be done and at what age they should begin is the proper question, not whether they should be eliminated.  
Henry Maze
San Mateo, Calif.

GARNICK REPLIES: Whether prostate cancer screening will reduce the death rates and suffering from prostate cancer forms a key and critical question underlying any screening program. The thinking behind such programs hypothesizes that cancers start as a microscopic focus, turn into a localized cancer—becoming more regionally advanced in the organ from which they arose—then metastasize, eventually claiming the life of the individual. Thus, screening and finding these cancers “early” should result in saved lives. Yet although nearly every screening program finds seemingly less aggressive and earlier-stage cancers than those found later on, the expected improved survival rates have not materialized.

Although it is reassuring to think that “catching” prostate cancer early will save lives, the complexities and differing genetic makeup of prostate cancers that ultimately determine the disease’s biological behavior are probably the most important factors. Oncologists remain hopeful that future biomarkers will be developed that will inform us not only of whether cancer is present but of what the behavior—and hence the need for treatment—of that cancer is likely to be.