The origin of life is certainly one of the most important outstanding questions in science today and not part of the current theory of evolution, which relies on the genetic system of life already being in place. In 1953, graduate student Stanley Miller, working under the guidance of the eminent chemist Harold Urey, made an amazing discovery in a very simple laboratory experiment. He found that the primary building blocks of life, the amino acids as well as other organic compounds, can be synthesized spontaneously by sending an electrical spark through a mixture of methane, hydrogen, ammonia, and water.50
At the time these were thought to be the ingredients of the primitive Earth’s atmosphere. Theists since have been quick to point out that the exact ingredients in the early Earth may have been different and concluded, therefore, that Miller’s results were no evidence for natural origin of life. Indeed, life did not spontaneously form from the ingredients in Miller’s experiment, and no one has yet managed that feat. However, many experiments have confirmed Miller’s findings with a wide range of gases.
The Miller-Urey result provided excellent evidence for a more general principle in nature that many people still find difficult to accept. They demonstrated, in the laboratory, that simple molecules can assemble naturally into more complex molecules. As described previously, this feature of simplicity evolving into complexity can be found in physics and other sciences besides biology, and disproves the argument made by proponents of intelligent design creationism that the existence of complexity in the universe cannot be explained naturally. In the case of life, since purely natural processes can generate the basic elements of life, no obstacle exists for their ultimate assembly into more complex forms.
Certainly the current biological cell itself is far too complex to have arisen by purely random processes, and no biologist claims it did. However, it is now well established in the laboratory that chemicals themselves evolve independently of the specific mechanisms of biological evolution.51 If the spontaneous formation of some complex system that had at least some of the properties of life were observed, then it would provide evidence that life had a natural origin.
The exhaustive review of the literature on life’s origins provided by Albrecht Moritz in the TalkOrigins Archive contains many examples of proposed mechanisms and provides extensive links to references. Moritz is conservative: “After critical study of the scientific literature I conclude that advances in our knowledge, with particularly exciting findings in the last decade, have now made the spontaneous origin of life a plausible assumption.”52 Recall that it only takes a plausible assumption to defeat the God-of-the-gaps argument.
See also the beautifully illustrated article “Life on Earth” by Alonzo Ricardo and Jack W. Szostak in the September 2009 issue of Scientific American.53 Here are the key concepts summarized by the editors:
Researchers have found that the genetic molecule RNA could have formed from chemicals present on the early Earth.
Other studies have supported the hypothesis that primitive cells containing molecules similar to RNA could assemble spontaneously, reproduce and evolve, giving rise to all life.
Scientists are now aiming at creating fully self-replicating artificial organisms in the laboratory—essentially giving life a second start in order to understand how it could have started the first time.
50. Stanley L. Miller, “A Production of Amino Acids Under Possible Primitive Earth Conditions,” Science 117 (1953): 528–29.
51. Paul F. Deisler Jr., “How Did Life Begin? A Perspective on the Nature and Origin of Life,” Skeptic 16, no. 2(2011): 34–40 and references therein.
52. Albrecht Moritz, “The Origin of Life,” TalkOrigins Archive, http://www.talkorigins.org/faqs/abioprob/originoflife.html (accessed December 17, 2009).
53. Alonzo Richardo and Jack W. Szostak, “Life on Earth: Fresh Clues Hint at How the First Living Organisms Arose from Inanimate Matter,” Scientific American (September, 2009): 54–61.