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Evolution is the scientific concept that life gradually adapts to changes in the environment through a process of mutation, natural selection and the struggle for survival. This idea was first described by Charles Darwin in 1859 and is now accepted as the most fundamental principle in all life sciences.
Although not explicitly mentioned in the Tipiṭaka, the idea of evolution is remarkably consistent with the Buddha’s teachings about the craving to live (bhavataṇhā), that everything changes (anicca) and that everything arises from natural causes rather that divine creation.
In the Aggañña Sutta the Buddha says that after the Earth came into being it was completely covered with water, that the first life-forms floated on the surface where they fed on nutrition and that they gradually changed from simple to complex over a vast period of time (D.III,84-88).
Buddhists have always believed that animals are worthy of love and respect, that humans can sometimes be reborn as animals or animals as humans and, therefore, they are quite comfortable with the concept of evolution.
When, in the course of a developing epoch a world reaches the stage at which life becomes possible, inorganic matter, by a natural process which biochemists may now be on the point of being able to duplicate, becomes transformed into cellular structure which exhibits the characteristics of life; that is growth and the assimilation of nutriment from its surroundings. Since doubt began to be felt about the theory of the supernatural creation of life on our planet, scientists have been seeking other explanations of its origin:
According to a report of C. Meunier, Louis Pasteur had conducted a series of experiments to ascertain whether viable bacteria or their spores existed in carbonaceous meteorites, the object being to discover whether the germs of life had reached the earth in debris of a shattered planet of our system. His results were negative and remained unpublished; but even had the panspermic theory, as it is called, proved to be correct it would still not have solved the problem of the ultimate beginning of life, but only shifted it a stage further back. At the time of writing it is generally believed by those who are studying this question that wherever life may have arisen in the universe it has done so independently.
The latest researches have revealed certain steps in the process of evolving living organisms which seems to give an outline of the necessary conditions and stages for life to appear. It has been known for a long time that some very rudimentary organisms, such as viruses, occupy a borderline position between the organic and inorganic, and these may well be the pattern of life in its initial stages. It now seems probable16 that at some point of the earth’s development a process of direct hydration of hydrocarbons occurred as the result of their combining with whole molecules of water.
The organic compounds then by interaction with ammonia yielded nitrous derivatives of hydrocarbons together with derivatives of oxygen. The data furnished by organic chemistry show that low molecular hydrocarbons and their oxygen and nitrous derivatives when in a humid atmosphere or an aqueous solution go through a far-reaching polymerization and condensation, which eventually leads to the formation of very complex substances, very closely resembling those that are found in the composition of living organisms.
In the earth’s primary hydrosphere many types of sugars and other carbohydrates could have been formed, and recent experiments have shown that such complex and at the same time widespread substances in organisms as porphyrines, nucleotides, and others can be synthesised from the simplest carbon and nitrogen compounds.
The next stage, that of the formation of the protein molecule, depends only upon the formation of amino acids, which are its basis. This has been illustrated by the experiments of S. Miller, who after passing electrical sparks through a mixture of methane, hydrogen, ammonia and water vapours was able to detect by the method of paper chromatography the presence of glycine, alanine and other amino acids in the solution. From these and other experiments which have shown how amino acids may be polymerized into chains of amino acid particles to form the basis of the protein molecule, a general plan of the process whereby the primary synthesis of proteins and other complex organic compounds could have taken place on the liquid surface of our planet is now made clear.
The problem, however, does not end there. To become living cells the protein bodies have to acquire the property of continually regenerating themselves from the substances that form their external environment. This process of self-regeneration and self-reproduction is not found anywhere in the inorganic world. It is metabolism which is the distinguishing characteristic of life. This involves a highly complicated series of co-ordinated activities in the organisation of living bodies.
Hundreds of thousands of chemical reactions must take place in a living body, and these not only combine harmoniously in a single sequence, but the entire order of events must be regulated to condition the self-preservation and reproduction of the vital systems, in conformity with the conditions of the external environment.
Therefore the origin of life is essentially the origin of metabolism, the processes of assimilation and dissimilation of nutriment and this, apparently, to a specific end.
The stage at which it arose in the simplest living organisms represented the vital point of transition from inert substance to living cell structure. Buddhism gives four modes by which living organisms come into existence, corresponding to four genetic types of beings, the oviparous (born of eggs), the viviparous (born alive), the moisture-generated and the abiogenic, or spontaneously arisen beings.
It is said that in the Developing Epoch beings were first born abiogenically, through the action of their past kamma operating on matter. Later on, this spontaneous arising of life gave place to sexual transmission of the seed, and beings became either oviparous or viviparous. Some commentators include fish and worms among the moisture-born, but there is no canonical authority for this; it was their own interpretation in the light of a belief which persisted even in England until the 18th century.17
In the Aggañña Sutta (Dīgha Nikāya) we are told that there was a period in the early history of the earth when great downpours of water covered its surface. It was in this liquid world that the spontaneously-arisen beings first appeared. They then lived subsisting on the nutriment they extracted from the surface of the water. It is not difficult to see in this, when allowance is made for the nature of the Pali language and the ideas it was capable of expressing, a very close approximation to what science now supposes to have occurred:
When solutions containing individual protein substances such as those we have been discussing are mixed together, the protein molecules which at first were evenly distributed throughout the solvent begin to unite in molecular piles. When one of these piles reaches a critical point in size, containing perhaps several millions of molecules, it separates into drops, which are called coacervates. All the proteins that were diffused in the solution now concentrate in these drops, while the surrounding liquid becomes deprived of any. Now these protein coacervate drops, despite their liquid consistence, evidently possess some kind of internal, very elementary organisation. They have a marked ability to absorb different substances from the solution around them.
The assimilated substances then begin to interact chemically with the substance of the drops themselves, chiefly with the proteins. In this way observation has shown that rudimentary processes of disintegration and synthesis of various substances are likely to take place in the drops. If by reason of their individual composition and structure, synthesis takes place more rapidly than disintegration under the given conditions of environment, the drops become dynamically stable formations so long as the given conditions exist, and they may not only persist for an indefinite time but can increase in bulk. They thus exhibit the two primary characteristics of life, assimilation and growth, although they have not yet attained the status of living organisms in the technical sense.
Just as in the laboratory tests which have demonstrated these facts, there must have been a time when the proteins or protein-like substances which originated in the water of the earth’s primary hydrosphere, had to form these complex coacervates. This in turn had to lead to the origination of a “natural selection” of these individual systems. The present theory as to how this came about rests on the assumption that the primordial waters were a solution of various organic substances and inorganic salts. These materials were absorbed by the coacervate drops and entered into chemical reaction with the substances of the drops, giving rise to the processes of synthesis and disintegration.
The efficiency of these parallel processes was determined by the internal organisation, of each individual drop. Consequently it was the drops which in the given circumstances of environment were endowed with a certain dynamic stability, on account of which the processes of assimilation and growth were faster than those of disintegration, which were able to exist for any length of time. Those which were not so suitably organised failed to survive for long, and contributed nothing to the future evolution of organic matter.
They vanished from the scene, while the drops which had the most perfectly adjusted organisation, their power to absorb fresh elements being in excess of the process of decomposition, continued to grow. They would increase in size until they reached a critical point once more, and then they would divide, forming smaller drops which each went its way, inheriting the basic dynamic stability which had characterised the original drops.
Such appears in outline the manner whereby nonliving matter became changed into rudimentary forms of life. It led ultimately to the origin of protein bodies with a fully organised metabolic system, the first truly living beings to appear on this planet.
Now this is all very well, but does the mechanistic view explain everything, when it has explained how life could originate abiogenically? Even when we grant that in the remote epoch we are discussing, there probably was an increase in the amount of organised substance and in the number of coacervate drops in the hydrosphere, and that the organisation of these drops was constantly changing to meet alterations in the environment, with those changes subject always to the rigid control to natural selection, it still seems very doubtful whether life would have evolved beyond the stage of the most perfect adaptability for survival, if there had not been some other factor besides natural selection at work.
Man has gone a long way beyond the point at which he became best fitted to survive; his directional trend now is, if anything, towards the acquirement of faculties more likely to lead to self-destruction than to further progress. And it would not be by any means the first time that natural selection had led a species to destruction.
Using the case of mankind to illustrate the point it may be arguable that it is when natural selection has reached the stage of perfect adaptability to environment that its effect is to work in reverse, precisely because it is a mechanical, not a purposeful, process.
But notwithstanding the powerful arguments in support of this view the fact that in the course of evolution nature produced beings which are not satisfied merely with coming to terms with their environment, but desire satisfactions that have nothing to do with survival—often, in fact, militating against it—introduces a disturbing element into the picture.
To ignore it would be to deny the existence of factors in human life that are at least as important as those of growth and procreation. What need of evolution is served, it might be asked, by those qualities which most distinguish man from the lower forms of life? Such qualities as, for example, self-sacrifice, idealism, concern for the welfare of others? Even among certain animals these characteristics, or something approaching them, are not entirely lacking; yet neither in man nor beast do they conform to the pattern of an activity governed only by natural selection. From that point of view they appear as nothing but aberrant forms of behaviour.
More than that in a world of mechanistic principles no cause can be assigned to them that would explain them away as sports of behaviour parallel to the sports of genetics. And a phenomenon without a cause is a fatal flaw in the system. If these are merely a superior form of conditional reflexes on the higher evolutionary rungs we are still under the obligation to discover by what they are conditioned and why these particular conditionings became effective in some individuals but not in others.
So far as I am aware, there is no theory which plausibly accounts for them on the lines of evolutionary necessity. Returning to the Buddhist view of evolution, we find it to be inseparable from the concept of moral order.
But the moral order, instead of being imposed from without, as part of a preconceived plan, is something which is inherent in the law of causality. The evolutionary ascent is preceded by a descent of beings whose deterioration led them to birth in grosser material forms. Thus, before the advent of the first unicellular micro-organisms it is said in the Aggañña Sutta that beings from the Brahmā-worlds came to spontaneous birth in planes adjacent to the terrestrial sphere, where they remained for a long time.