10. Life: A
brief philosophical review
Safety Research and Health Physics Group, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu 603 102
Questions such as what life is, how life
originated, what is the meaning and purpose of life, have haunted
man from the dawn of history. Various answers also have been given
at different stages of history. This is a brief summary of our
present day understanding on the basis of the findings of science.
What is life? How did life originate ? More particularly how did human life arise? What is the meaning and purpose of life? What is death? These are questions that have haunted mankind from time immemorial. All these questions are related to one another in one way or the other, and hence the answers also ought to be sought in a correlated manner.
The most pertinent and the central one among these questions is "How did life originate?". One answer which has been prevalent for centuries and which is still prevalent among the majority of people is that "Everything in the universe including life is the work of a supernatural creator". This is a fairly simple and comfortable answer. It is comfortable because it spared man the arduous task of finding out answers to the complicated and disturbing questions concerning matter and life. Everything that is known and unknown could be attributed to that supreme unknowable. Probably, the then existing social systems also had their compulsions to perpetrate this convenient idea. This idea is the basis of all religious and idealist philosophies. But human's actual experience contradicts with this idea and often militates against it. But in the absence of a comprehensive scientific understanding based on rigorous experimentation and verification, plausible alternatives could not be proposed.
A break in the long lull came with the renaissance and the dawn of modern sciences. The advancements made in the physical sciences, particularly in mechanics with the expounding of the laws of mechanics by Galileo, Newton and others, a mechanical materialistic view of the world came to the fore. According to this view, the material world including life was conceived as a mechanical process akin to machines. This approach also strengthened the hypothesis of spontaneous generation of life from non-life. In this scheme, worms spontaneously arose from mud, maggots from decaying meat and so on. The spontaneous generation hypothesis also could not do away with the prime mover or the creator and is not basically different from the creationist idea. This hypothesis was originally proposed by the Greek philosopher Aristotle and even up to the middle of the 19th century it was generally held as scientific. The death knell for this theory was sounded by the rigorous experiments conducted by Louis Pasteur in the 1850s.
The foundation of our present day understanding of life and its development was laid down by the epoch-making discovery of the evolution of life by Charles Darwin. In the book "The Origin of Species" published in 1859, Darwin outlined the essential feature of the "secret of life", the unfolding of the process of evolution of higher forms of life from the lower forms through the mechanism of natural selection. The discovery of genetics, originally made by Gregor Mendel in 1860s and its dramatic advancements in this century, laid bare the molecular basis of life. The mystery of life was further unfolded by the theory of chemical evolution, first propounded by A.I. Oparin in 1924. Independently of Oparin, J.B.S. Haldane in 1928 proposed the concept of the `primordial soup', the probable conditions leading to the emergence of life on earth. Another landmark in the historical and scientific development of the subject was the classic paper of J.D. Bernal entitled "The physical basis of life", published in 1947. In the words of Cyril Ponnamperuma: "Historically however all these ideas were forestalled by Charles Darwin in that celebrated letter to his friend Hooker in which he described a warm little pond filled with ammonia, phosphoric salts etc. from which a protein compound was formed ready to undergo still complex changes. Here in a nutshell is the entire concept of chemical evolution".
On the basis of the historical background briefly described, and in the light of the findings of science, let us try to answer the questions one by one. What is life? Life is the product of the development of matter. It is the complex organisation of matter having the property to assimilate the required constituents to reproduce itself. The kernel of life is the self replicating molecule of life , the DNA. In the words of J.D. Bernal: " We can now turn round and define life in molecular terms. Extending Engels, we could say `life' is the mode of motion of the protein-nucleic acid combinations".
How did life originate? According to the theory of chemical evolution, life on earth arose from non-life about 3500 to 4000 million years ago through a long process of chemical evolution spread over millions of years. The age of the earth has been reasonably estimated to be 4500 million years. The progression of chemical evolution may be regarded as taking place in distinct and successive phases from the inorganic to the organic, and the organic to the biological. In his treatise Oparin stated "There is no fundamental difference between a living organism and life-less matter. The complex combinations of manifestations and properties so characteristic of life must have arisen in the process of the evolution of matter".
How did human life arise? The evolution of higher forms of life from lower forms through the intricate mechanism of natural selection was exhaustively and conclusively established by Darwin in his treatise "The origin of species". Human beings are also the product of evolution. In his book "The Descent of Man", published in 1871, Darwin gives a detailed description of the emergence of man through the process of evolution.
What distinguishes human life from other forms of life? In the course of evolution, in organisms there developed the nervous system, which on further development resulted in the central nervous system or the brain. According to I.P. Pavlov, the celebrated physiologist whose pioneering studies led to the scientific understanding of mind-matter relationship, brain is the organ of the most complicated relations of the animal to the external world. Mental activity is the activity of the brain whereby the animal relates itself to the external world. The first form of conscious awareness of things is sensation, which arises from the development of conditioned reflexes. The term `sensation' denotes the particular signals of connections between the animal and the external world resulting from different stimulation of the different sense organs. Sensation develops into perception when an integration of the response to many sense-stimulations takes place in the brain. Continuously responding to and recognising the signals received from its senses, the animal learns to relate sensations together so that together they afford a complex representation of complex objects in complex relations - this is called perception. In animals the mental activity is restricted to sensations and perceptions.
With the development of the enlarged cerebral cortex in the human brain, in addition to sensations and perceptions which animals also posses, human brain acquired a new quality, the ability to think, to conceive ideas. After his emergence, man underwent an evolution, not a biological one, but social. With the ability to think and convey his thoughts to fellow men through the medium of language, man acquired a new form of consciousness namely social consciousness. The sense of ethics, morality, etc. unique to man has arisen from his social consciousness. On this consciousness was built society and its civilisation which distinguishes man from all other animals.
Purpose of life: Life, when it originated, had no purpose as such. Life had resulted from a combination of several random events spread over millions of years and it would not be an exaggeration to say that it was a great accident. With the emergence of man endowed with the power of thinking, which enabled him to understand life itself, it is an altogether different story. Man, the creator of civilisation and culture, has a great purpose in life, and that is to play the conscious role to create conditions conducive to the development and perpetration of life and civilisation.
What is death? An organism dies when
the life process ceases in the organism or that particular organisation
of matter responsible for the life property is destroyed. This
is applicable to human life as well. Even though individual organisms
do have an end in death, life itself can be said to be immortal.
In the words of J.D. Bernal: "The last word about death has
still to be spoken, the important thing is not death of the individual
man or species but the effective immortality of life itself, that
is the effective reproducibility of genetic carrying nucleic acid
molecules. What I am attempting to say is `Life does not die'
but more accurately to have to admit that `Life has not died'
and that potential calamity is still with us".
Life is the product of development of
matter. Life in the course of development and evolution produced
man with the ability to think. Man underwent an evolution not
a biological one, but social, which created society and civilisation.
The purpose of life, as far as man is concerned is to play his
conscious role in creating conditions conducive to the onward
march of life and civilisation.
1. Bernal, J.D., The physical basis of life, London, 1951.
2. The physiological teachings of I.P.Pavlov, Moscow, 1951.
3. Maurice Cornforth, Dialectical Materialism: An Introductory course, London, 1954.
4. Cyril Ponnamperuma, The origins of life, London, 1972.
To Bioethics in India book contents
To Eubios Ethics Institute books
To Eubios Ethics Institute home page