The Extraterrestrial Life Debate
Historical, Philosophical and Scientific Perspectives
U.S. Naval Observatory
About the Lecture
Extraterrestrial life has been one of the major themes of 20th century science, and has roots that go back to ancient Greece. Because the debate has been at the very limits of science, it is a window on how science has functioned with little data, attempting to answer a question of profound importance to humanity's place in the universe. Today the discovery of the Martian meteorite, life in extreme environments, a likely ocean on Europa, and some 50 planets beyond our Sun assures that the search will intensify in the 21st century.
In this lecture, I will provide historical background to the subject, examine the current debate, assess the likelihood of life beyond Earth, and summarize the philosophical implications. Whether cosmic evolution ends in planets, stars and galaxies, or in life, mind and intelligence, will determine the long-term future of humanity. The very search for a "biological universe" affects our world view today, just as Copernicanism and Darwinism affected the short-term and long-term future.
About the Speaker
Steven J. Dick has worked as an astronomer and historian of science at the U.S. Naval Observatory since 1979. He obtained his B.S. in astrophysics (1971), and MA and PhD (1977) in history and philosophy of science from Indiana University. Best known as an historian of the extraterrestrial life debate, his doctoral dissertation was published as Plurality of Worlds: The Origins of the Extraterrestrial Life Debate from Democritus to Kant (1982) . He tackled the entire scope of the twentieth century debate in The Biological Universe: The Twentieth Century Extraterrestrial Life Debate and the Limits of Science (Cambridge University Press, 1996) , and its abridgement and update Life on Other Worlds (1998) . The latter works argue that the idea of extraterrestrial life is a world view analagous to the Copernican theory, with widespread implications. Dick has written on these implications, notably in a volume he edited entitled Many Worlds: The New Universe, Extraterrestrial Life and the Theological Implications (2000) . Dick has served as Chairman of the Historical Astronomy Division of the American Astronomical Society (1993-1994), and as President of the History of Astronomy Commission of the International Astronomical Union (1997-2000).
He is currently working on a history of the U. S. Naval Observatory.
Find his books at Amazon.com:
Plurality of Worlds: The Origins of the Extraterrestrial Life Debate from Democritus to Kant (1982) (Out of print)
The Biological Universe: The Twentieth Century Extraterrestrial Life Debate and the Limits of Science (Cambridge University Press, 1996)
Life on Other Worlds (1998)
Many Worlds: The New Universe, Extraterrestrial Life and the Theological Implications (2000)
President Spargo called the 2120th meeting to order at 8:15 p.m. on, October 6, 2000. Mr. Grant, a former Recording Secretary of the Society read the minutes of the 2119th meeting and they were approved as read.
The speaker for the 2120th meeting was Steven J. Dick. The title of his presentation was “The Extraterrestrial Life Debate: Historical, Philosophical and Scientific Perspectives”. Mr. Dick is an astronomer and historian of science at the U.S. Naval Observatory.
Before launching into his talk, Mr. Dick noted that three former Presidents of the Society had been astronomers from the U. S. Naval Observatory:
Simon Newcomb – Second President (1879-80) and successor to Joseph Henry
William Harkness – Ninth President (1887)
W.S. Eichelberger – Thirty-Seventh President (1915)
When the speaker speculated that the Society may have had other speakers from the U.S. Naval Observatory in the past 85 years there were affirmative murmurs from the audience.
Whether there is extraterrestrial life is a major question of our time. The discovery of the Martian meteorite, life in extreme environments, a likely ocean on Europa (a moon of Jupiter), and some 50 planets beyond our Sun assures that the search for extraterrestrial life will intensify in the 21st century. The speaker provided a historical background on the subject, examined the current debate, assessed the likelihood of life beyond the Earth, and summarized the philosophical implications.
The philosophical debate goes back to ancient Greece. Questions about the origin of life – whether it is “written into the laws of nature” or the result of a freakish accident unique to our planet, about evolution – whether there is compelling evidence for or against the Darwinian assertions of directed ingenuity and creative adaptation, and about the theological implications of extraterrestrial intelligence – of finding, if we should, after thousands of years of speculation, that we are not alone, have long engaged the leading thinkers.
The idea of extraterrestrial life is a world view analogous to the Copernican theory, with widespread implications. The Copernican theory of a heliocentric universe, which replaced the geocentric universe, took more than a thousand years to be accepted. It eventually gave birth to a new physics, caused wrenching controversy in theology, and made the Earth a planet and the planets potential earths. Few other revolutions in history have had such broad, if delayed, consequences. The galactocentric revolution in the early 20th century, on the other hand, is an example of a silent revolution, largely because the galactocentric model did not pose a threat to societal institutions. When scientific revolutions impinge upon metaphysics or social theory they are likely to become unusually polemical and possibly unacceptable. The speaker suggested that the consequences of the discovery of extraterrestrial intelligence will likely follow the Copernican pattern.
Today there are two views of the cosmic evolution that began with the “Big Bang,” a physical universe, consisting of planets, stars and galaxies, or a biological universe. Within astro-biology the debate is whether is it a weak biological universe, teeming with microbes and simple biological forms, or a strong biological universe with multiple centers of intelligent life. Still, there is no scientific evidence for a biological universe. All theories, including the potential evidence of life on the Mars meteorite, have been proven false.
Nevertheless, most people seem to believe there must be extraterrestrial life. An answer to Fermi's famous questions: “Where are they? Why haven't we seen any traces of intelligent extraterrestrial life?” is the Drake equation conceived as a means to estimate mathematically the number of worlds that might harbor intelligent life. The speaker believes the importance of the Drake Equation is not in the solving, but rather in its contemplation. Specifically, the very search for a “biological universe” affects our world view today, just as Copernicanism and Darwinism affected the short-term and long-term future. Whether the cosmic evolution ends with planets, stars and galaxies – the physical universe, or with life, mind and intelligence – the biological universe, will determine the long-term future of humanity.
Mr. Dick kindly answered questions from the floor. President Spargo thanked Mr. Dick for the Society, and welcomed him to its membership. The President then announced the next meeting and made the usual parking announcement and adjourned the 2120th meeting to the social hour at 9:28 p.m.
Willard S. Grant
The Drake Equation
Dr. Frank Drake conceived a means to estimate mathematically the number of worlds that might harbor beings with technology sufficient to communicate across the vast gulfs of interstellar space. The Drake Equation, as it came to be known, was formulated in 1961 and is generally accepted by the scientific community.
N = R* fp ne fl fi fc L
N = the number of communicative civilizations
R* = the rate of formation of suitable stars (such as the Sun)
fp = the fraction of those stars with planets (current evidence indicates that planetary systems may be common for sun-like stars)
ne = the number of Earth-like worlds per planetary system
fl = the fraction of those Earth-like planets where life actually develops
fi = the fraction of life sites where intelligence develops
fc = the fraction of communicative planets (those on which electromagnetic communications technology develops)
L = the “lifetime” of communicating civilizations.