WHAT IS LIFE? DEFINE LIFE. |
In the literature on the science/religion debate, numerous references are made to the 'origin of life'. I started pondering - well before we can talk about the origin of life we must have a comprehensive definition of LIFE. What is life? Definitions in dictionaries are very unsatisfactory. Students taking biology classes could not define. I began to search the literature and found that a specific definition is usually lacking. The following, published in the UWO Western NEWS, October, 24, 1996 summarizes my research, provides a definition of LIFE, a brief summary of comments, and my comments on the significance and implications.
The debate in the United Kingdom about the disposal of frozen embryos raises once again two questions - What is Life? What is the Origin of Life? These embryos in their present frozen state are not alive and therefore do not possess life. Only if they are implanted do they have the potential of developing into a living human being, who has LIFE!
In addition, a potato-size rock fragment with an age of about four billion years, found in Antarctica twelve years ago, and identified as originating on Mars, contains microscopic structures, suggesting primitive life-forms. [See GSA TODAY,July 1997,p.1] Are they? Just what is life?
In 1993, I organized at the biennial International Society of History, Philosophy, and Social Studies on Biology (ISHPSSB) conference at Brandeis University, Waltham, Massachusetts, a symposium entitled - WHAT IS LIFE? DEFINE LIFE, as a preliminary step in yet another attempt to examine the beginnings or origin of life. In preparation, definitions from several dictionaries were compiled. Most were considered useless. A multitude of books and articles were searched and a list of 22 definitions were assembled. An article by J.B.S. Haldane, published in 1947 entitled "What is Life?" opened with the statement 'I am not going to answer the question - ' but he did include a critical aspect incorporated in the definition below. The ISHPSSB membership was invited through the NEWLETTER to submit definitions of less than 150 words. The submissions were disappointingly few, and some so long and complex, using technical language, I considered them incomprehensible.
Before the conference, the definitions from dictionaries, books, articles, and personal submissions were distributed to the contributors, and at the conference. At the session after a preliminary statement by the organizer, the discussion was vigorous, dominated by three or four individuals. Every individual in the audience was asked to make a statement, and a couple were most helpful; reluctance to speak by some individuals at a group meeting is a common characteristic. One participant was most verbose until the organizer intervened and terminated his interjections, as he seemed determined defining LIFE should be avoided. Two concepts did emerge but not with unanimous agreement. 1) A free living single cell, such as an amoeba, is alive and therefore exhibits life. 2) a virus which can exist only within another organism, is not alive so does not exhibit life.
Subsequent to the meeting, on the basis of the compiled definitions and the meeting discussion, the following definition of life was composed.
Life is a succession of energy-producing electro-chemical processes by a naturally occurring, simple or complex organism composed of a combination of molecules, each consisting or systematically arranged carbon, hydrogen, and oxygen atoms, and a few other elements, forming cells, which consume 'food' and produce 'waste', both consisting of solid, aqueous, and gaseous matter; the process is called metabolism; the organism is capable of living within the environment without dependency on any other organism; energy use is manifest by growth with size limits for most; self-healing; possibly movement; self-replication with each offspring slightly different; irritability; capable of modifying their living environment, both beneficially and detrimentally; with eventual termination of energy production, or death. exceptions are egg, sperm, spore, seed, and virus, which do not consume food and produce waste; the first four are replication structures, and the fifth has premature life-terminating capabilities. (about 146 words) revised 96-08-26.
Does this definition have any official status such as endorsement by a professional scientific, philosophical, legal, government, or other organization? NO! the purpose for publishing is to draw attention to the fact that a rational discussion about the beginnings or origin of life, demands that a comprehensive definition of life is a prerequisite. this should also hold for the debate about those frozen human embryos, and microscopic structures in a piece of rock which is presumed to have come from mars. otherwise the only fruits of the debate are an increase in the carbon dioxide content of the atmosphere.
The following summarizes "letters-to-editor" in the uwo campus newsaper, and comments of correspondents.
This definition now allows the question - what actually happened when life originated? there is also the question - where did life originate? a common tendency is -- out there, and then transported to earth!! that merely begs the question about the origin of life. i believe that life originated here - on earth, and not elsewhere. the american astrophysicist, harlow shapley described earth as a grain of sand, with a whiff of atmosphere, a film of water, and a smear of biology, plodding its way around the sun with monotonous regularity. another question is when did life originate? the oldest rocks on earth with entities considered as fossils, have a date of about 3.7 billions of years.
then there is the question - did life originate by chance or design? a basic assumption of the entire spectrum of scientific research is to establish order, or system, or a classification from which predictions can be made. in his book the blind watchmaker, richard dawkins wrote on the final page (p.317) "The true explanation for the existence of life must embody the very antithesis of chance". allow me to state in the positive - the existence of life must embody design!
C. Gordon Winder, University of Earth Sciences, London ON Canada, N6A 5B7
Slightly modified 01/05/11.