Extraterrestrial intelligence: the debate continues. The readers respond to Tipler

We compliment PHYSICS TODAY for its stimulating guest comment in the April ‘81 issue by Frank J. Tipler (“Extraterrestrial beings do not exist,” April, page 9). As research physicists in specialties far removed from astrophysics and extraterrestrial biology, but intrigued by Carl Sagan's (and others') unquestioned assertion that numberless intelligent civilizations exist elsewhere in the universe, we have been struck by the paucity of critical response to this hypothesis. This lack being quite an uncharacteristic reaction by the scientific community to what is a controversial proposition. However, with Tipler's counterpoint, it now appears that an opposite view is alive and well, PHYSICS TODAY and Tipler have provided the required first step for the scientific community's consideration, and the usual and absolutely necessary polemics may now proceed.