The Sciences



Sign up for our email newsletter for the latest science news

Out-of-body experiences

Science is a discipline based on accurate reporting of facts and requiring that opinions and theories be based on and true to relevant facts. Discover magazine has failed to respect these basic requirements of science in Steven Kotler’s “Extreme States” article on out-of-body and near-death experiences [July]. There are several instances where the writer’s reporting and interpretation of factual data is questionable, but I will deal with just those where he casually maligns me. Kotler states, “Both phenomena have had a serious credibility problem. Much of it stems from the scientists who did the earliest investigations. Charles Tart, a psychologist at the University of California at Davis, who did the first major study of out-of-body experiences in 1969, and Raymond Moody . . . designed experiments of questionable rigor and made matters worse by ignoring the peer-review process and publishing their results in best-selling books.” Facts: My first major study of out-of-body experiences was published in 1968, not 1969, and was published in a peer-reviewed journal, not a best-selling book. Readers may, for convenience, access a reprint of that paper (“A Psychophysiological Study of Out-of-the-Body Experiences in a Selected Subject,” Journal of the American Society for Psychical Research 62, 3–27) at my web archive.

I have mentioned that study in later books of mine but cite the original reference—something Mr. Kotler must not have bothered to consult. As to “questionable rigor,” it was the first modern laboratory experiment of the phenomenon, so I naturally pointed out ways in which future studies could be improved—that is a standard part of science writing. My conclusion as to what the study had found? “It is hoped that the present study, insofar as it has shown that these experiences can be studied by the techniques of modern science, will encourage other investigators to carry out further experiments” (page 23). It was quite successful in breaking the ground for others to follow. As to “Both Tart and Moody later wrote follow-up books partially debunking and partially recanting their previous ones,” Kotler must have dreamed this up. I have never “debunked” or “recanted” my original research article, and I stand by its 1968 report of facts and data today, more than 35 years later. Discover should, as many other popular magazines do, employ fact-checkers, especially when dealing with controversial material.

Charles T. Tart

Professor, Institute of Transpersonal Psychology, Palo Alto,


Professor Emeritus, University of Calif. at Davis

Discover does employ fact-checkers, and we take that responsibility very seriously. We apologize to Professor Tart for publishing certain incorrect facts in the article and for not being persistent enough in trying to reach him to address criticisms of his work. Tart is a pioneer in consciousness research. 

The editors

A palpable hit?

Planetary scientist H. Jay Melosh is of course correct that the Deep Impact probe will have a negligibly small effect on comet Tempel I’s orbit [“Impact Geologist Waits for the Big One to Hit,” Discover Dialogue, July]. But over the really long term, orbits in the solar system are chaotic. Moving it a micron now might move it too close to Jupiter a billion years from now. Jupiter might slingshot it out of the solar system or into a collision with Earth. Melosh asserts that an impact in the oceans “would not be terribly bad.” Has he considered the damage caused by the resulting tsunami?

Frank Weigert

Wilmington, Delaware

It is true that comet Tempel 1’s chaotic orbit is unpredictable over the very long term. The essence of chaos is that any small initial perturbation grows exponentially over a term controlled by the size of the “Liapunov exponent.” Most of the perturbations suffered by the comet are due to the irregular venting of gas and dust and are much larger than the impulse Deep Impact will deliver. Therefore, it would be impossible to attribute any particular orbital change in the future to Deep Impact. Moreover, long before the Liapunov exponential time has elapsed, the comet will be gone, evaporated by the sun, like innumerable previous comets, whose only remaining trace is a periodic meteor shower. I have indeed considered impact tsunamis, which in my opinion have been the subject of outrageous hyperbole. Don Korycansky’s current work at the University of California at Santa Cruz confirms the discovery of the Van Dorn effect in the 1960s under the auspices of the U.S.

Naval Research Laboratory. The effect predicts that explosion- and impact-generated tsunamis will break on the continental shelf and thus will not cause large run-ups onto land. This is a consequence of the wavelengths of impact-tsunami waves, which are between that of storm waves (tens of meters) and earthquake tsunamis (hundreds of kilometers). Local impact-tsunami damage is known from the gigantic Chicxulub impact on Yucatán 65 million years ago, but at that scale of impact, tsunamis were the least of the hazards faced by Earth’s biota.

Contrast and Compare

H. Jay Melosh

Regarding the June letter from James Bramson of the American Dental Association in response to “Our Preferred Poison,” your March feature about mercury: Mr. Bramson’s choosing to draw an analogy between table salt (a chemical compound) and mercury fillings (an amalgam, as he states) would make anyone with an elementary knowledge of chemistry feel less than reassured. If this is the ADA’s best counterargument against those concerned about mercury exposure from amalgams, one wonders whether this organization is remotely qualified to judge the health dangers of this or any product.

Jeff Miller

Belmont, California

Doctor, doctor, give me the news

I enjoyed “Dr. Mushroom” [July] and share Greg Mueller’s passion for fungi. His statement “We don’t have an antidote for the amatoxins” (acquired by ingesting the Amanita virosa mushroom) may be true in the United States, but not in Europe. Thanks to the application of the German Commission E Monograph study of medicinal plants, an amanita-poisoned patient brought to a European emergency room could receive intravenous silymarin, a complex of milk-thistle constituents. Silymarin was cited in the Commission E study as a supportive treatment for inflammatory liver conditions and as a life-saving treatment in cases of poisoning.

Nancy Collins

Statesboro, Georgia

Remember the plants

I enjoyed your July Think Tank 25-year review and forecast of paleontology. It was a good summary of many important advances in vertebrate and primate paleontology. However, there was a glaring omission. Your plant blindness is showing. I’m sure that there were important advances in our understanding of plant evolution in the last 25 years and that there are paleobotanists out there with thoughtful insights to share. Animal evolution did not happen in isolation from other life, especially plant life. Without land plants, the most complex terrestrial life would most likely be a microbial crust.

Priscilla Spears

Conifer, Colorado

1 free article left
Want More? Get unlimited access for as low as $1.99/month

Already a subscriber?

Register or Log In

1 free articleSubscribe
Discover Magazine Logo
Want more?

Keep reading for as low as $1.99!


Already a subscriber?

Register or Log In

More From Discover
Recommendations From Our Store
Shop Now
Stay Curious
Our List

Sign up for our weekly science updates.

To The Magazine

Save up to 70% off the cover price when you subscribe to Discover magazine.

Copyright © 2023 Kalmbach Media Co.