Tuesday, June 17, 2014
Tuesday, June 03, 2014
Evidence for Creative observance
For many years paleontologists have been remarking upon the absence of certain essential links with which to complete, in Arthur O. Lovejoy's phrase, "The Great Chain of Being." There is something disturbing about these breaks in the record, and great rejoicing has occasionally resulted from finding some transitional form, such as the Polyp Hydra (linking animal and vegetable), and the Archaeopteryx which bridged the gap from reptiles to birds -- or so it seemed. Moreover, where such links were still missing, there were often those who were willing to supply them. One very famous practical psychologist, P. T. Barnum, did just this, supplying many such missing links in an exhibit which was part of a larger collection of curiosities the public was invited to see in 1842, seven years before Darwin's Origin of Species was published. The advertisements of the day heralded this exhibition in New York City, which began the American Museum, formed by combining Scudder's and Peele's Museums. It was enlivened with freak shows and stage entertainment. Perhaps some of the reconstructions in present day museums are still in the Barnum tradition!
Gaps in the Record
At first the authorities, faced with the existence of such gaps, attributed this to the "incompleteness of the geological record." When one or two of these missing links were later discovered, their plea seemed to be quite justified. Given time, the chain would be forged completely. But this has not proven to be the case. The missing links persist at many critical points, and there are not a few authorities today who believe that they never will be found. Either they have been destroyed, or evolution has been discontinuous. This
does not mean that they now believe in direct creation by a personal Creator but rather that the small jumps resulting from mutations as currently observed have at times and for unknown reasons been much larger -- large enough, in fact, for a reptile at one fell swoop to suddenly become a warm-blooded feathered fowl. This kind of jump was not termed a mutation but a saltation by R. Goldschmidt. A single quotation from this authority will serve to show what he had in mind when he spoke of saltations:
At first, Christians were quick to underscore the gaps as evidence of the intervention of God. Here, they felt sure, evolution must be abandoned and creative activity introduced. But then inevitably some of the gaps began to be filled in. Those who were a little more far-seeing warned that it was dangerous to emphasize these gaps as evidence of creative activity for two reasons: first, because if they were reduced in number, God would be made smaller and smaller; and secondly, because it tended to minimize the continuous sustaining activity of the Creator in the day to day workings of Nature, reducing God's activity not to sustaining the world but to special interferences in it. In recent years this warning has been issued more and more loudly in spite of the fact that evolutionists themselves have been more and more ready to admit the persistence of the gaps The question is, then, do we need to surrender this evidence of creative activity? If we are careful to remain aware of the fact that God is not merely the God of the gaps but the God of the continuities also, we shall not need to relinquish what seems to me a very strong evidence of direct creation.
We do not believe in God simply because gaps exist, which seem to demand a God to fill them. We know these gaps exist at present, and there seems every likelihood that they will persist, and so we merely say as Christians, "Such gaps may well be points at which God was at work by directly creative means." But the fact is that the scientist with a Christian faith does not actually find himself any less eager to fill in the gaps if he can. It is true that his faith may make the search less important, but it may supply him with a compensating drive -- the desire to explore God's handiwork in creation simply because it is His handiwork. Moreover, few if any paleontologists ever set out specifically to discover a missing link whose form they have already conceived as intermediate between two other divergent forms. They search for fossil animal remains and if they happen to come across an intermediate form, they rejoice as one who finds great spoil. But so would the Christian paleontologist! One's faith in the reality of a Creator who had a purpose really has no bearing on it. Finding an intermediate form like an Archaeopteryx is not really the reward of diligence (though diligence is required), but simply good fortune for the finder. It may seem otherwise with supposed intermediate forms between man and the apes, but here the situation is a little different, because any fossil ape is taken almost automatically as a missing link, even though the finder knows perfectly well that given a certain basic skeletal structure of similar proportions, a like habitat, and a similar source of food, convergence will almost guarantee parallel development. It is only what one might expect. It would be surprising if this were not so.
In some ways, the Christian research worker is in an advantageous position: he may be kept, by his knowledge of the Bible, from making some of the ludicrous mistakes made by eager exponents of man's animal ancestry, such as the construction of Mr. and Mrs. Hesperopithecus out of the tooth of a wild pig. And in so far as he reports upon findings of fossil remains of creatures below man, he may like Hugh Miller achieve an eloquence unattained by the indifferent evolutionist, who sees only data in what he finds. Modern works on geology or paleontology are, by and large, atrociously dull and have none of the eloquence of, for instance, Miller's The Testimony of the Rocks.
Gaps exist all down the line from the very beginning to the very end of the record, from the Cambrian Era to the Pleistocene Age, from non-living to living, from vegetable to animal, from invertebrate to vertebrate, from cold- to warm-blooded, from animal to man. These are merely the major areas in which gaps exist. Gaps appear also between Orders, Classes, Families, Genera, and Species. In the total view it could quite reasonably be argued that there is not one missing link, i.e., between animals and man, but a least a million missing links since there are over a million species. Of course, gaps between species are not really admitted, they are supplied by imagination. But at the other levels they are acknowledged.
Between the non-living and the living, there is a gap. There are some who hold that the viruses supply a bridge, but this is not generally conceded.
To be continued . . .
At first the authorities, faced with the existence of such gaps, attributed this to the "incompleteness of the geological record." When one or two of these missing links were later discovered, their plea seemed to be quite justified. Given time, the chain would be forged completely. But this has not proven to be the case. The missing links persist at many critical points, and there are not a few authorities today who believe that they never will be found. Either they have been destroyed, or evolution has been discontinuous. This
does not mean that they now believe in direct creation by a personal Creator but rather that the small jumps resulting from mutations as currently observed have at times and for unknown reasons been much larger -- large enough, in fact, for a reptile at one fell swoop to suddenly become a warm-blooded feathered fowl. This kind of jump was not termed a mutation but a saltation by R. Goldschmidt. A single quotation from this authority will serve to show what he had in mind when he spoke of saltations:
At this point in our discussion, I may challenge the adherents of the strictly Darwinian view, which we are discussing here, to try to explain the evolution of the following features by the accumulation and selection of small mutants; hair in mammals, feathers in birds, segmentation in arthropods and of vertebrates, the transformation of gill-arches in phylogeny, including the aortic arches, muscles, nerves, etc.: further, teeth, shells of molluscs, ectoskeletons, compound eyes, blood circulation, alternation of generations, statocysts, ambulacral system of ecinoderm, pedicellara of the same, enidocysts, poison apparatus of snakes, and finally, primary chemical differences like hemoglobin versus hemocyanin, etc. No one has accepted this challenge! Corresponding examples from plants could be given.In other words, Goldschmidt argues that there have occurred at many points sudden and radical changes of form involving at times the whole organism, so pronounced as to be quite unexplained by gene mutations. His major antagonist, Dobzhansky, completely disagrees. But on one thing both concur, namely, that blind evolution accounts for everything.
At first, Christians were quick to underscore the gaps as evidence of the intervention of God. Here, they felt sure, evolution must be abandoned and creative activity introduced. But then inevitably some of the gaps began to be filled in. Those who were a little more far-seeing warned that it was dangerous to emphasize these gaps as evidence of creative activity for two reasons: first, because if they were reduced in number, God would be made smaller and smaller; and secondly, because it tended to minimize the continuous sustaining activity of the Creator in the day to day workings of Nature, reducing God's activity not to sustaining the world but to special interferences in it. In recent years this warning has been issued more and more loudly in spite of the fact that evolutionists themselves have been more and more ready to admit the persistence of the gaps The question is, then, do we need to surrender this evidence of creative activity? If we are careful to remain aware of the fact that God is not merely the God of the gaps but the God of the continuities also, we shall not need to relinquish what seems to me a very strong evidence of direct creation.
We do not believe in God simply because gaps exist, which seem to demand a God to fill them. We know these gaps exist at present, and there seems every likelihood that they will persist, and so we merely say as Christians, "Such gaps may well be points at which God was at work by directly creative means." But the fact is that the scientist with a Christian faith does not actually find himself any less eager to fill in the gaps if he can. It is true that his faith may make the search less important, but it may supply him with a compensating drive -- the desire to explore God's handiwork in creation simply because it is His handiwork. Moreover, few if any paleontologists ever set out specifically to discover a missing link whose form they have already conceived as intermediate between two other divergent forms. They search for fossil animal remains and if they happen to come across an intermediate form, they rejoice as one who finds great spoil. But so would the Christian paleontologist! One's faith in the reality of a Creator who had a purpose really has no bearing on it. Finding an intermediate form like an Archaeopteryx is not really the reward of diligence (though diligence is required), but simply good fortune for the finder. It may seem otherwise with supposed intermediate forms between man and the apes, but here the situation is a little different, because any fossil ape is taken almost automatically as a missing link, even though the finder knows perfectly well that given a certain basic skeletal structure of similar proportions, a like habitat, and a similar source of food, convergence will almost guarantee parallel development. It is only what one might expect. It would be surprising if this were not so.
In some ways, the Christian research worker is in an advantageous position: he may be kept, by his knowledge of the Bible, from making some of the ludicrous mistakes made by eager exponents of man's animal ancestry, such as the construction of Mr. and Mrs. Hesperopithecus out of the tooth of a wild pig. And in so far as he reports upon findings of fossil remains of creatures below man, he may like Hugh Miller achieve an eloquence unattained by the indifferent evolutionist, who sees only data in what he finds. Modern works on geology or paleontology are, by and large, atrociously dull and have none of the eloquence of, for instance, Miller's The Testimony of the Rocks.
Gaps exist all down the line from the very beginning to the very end of the record, from the Cambrian Era to the Pleistocene Age, from non-living to living, from vegetable to animal, from invertebrate to vertebrate, from cold- to warm-blooded, from animal to man. These are merely the major areas in which gaps exist. Gaps appear also between Orders, Classes, Families, Genera, and Species. In the total view it could quite reasonably be argued that there is not one missing link, i.e., between animals and man, but a least a million missing links since there are over a million species. Of course, gaps between species are not really admitted, they are supplied by imagination. But at the other levels they are acknowledged.
Between the non-living and the living, there is a gap. There are some who hold that the viruses supply a bridge, but this is not generally conceded.
To be continued . . .
Saturday, May 10, 2014
Evolution and a Succession of Forms
In giving introductory courses in the life sciences, which are naturally presented from the evolutionary point of view, university professors often refer to the "Evolutionary Base Line." By this is meant a succession of forms of life which are chosen to represent what are believed to be the basic steps in the process of development from amoeba to man.
This base line begins with unicellular forms such as Paramecia, but it is worth noticing that an authority like Gaylord Simpson considers the step from no life to amoeba as being as great as the whole passage from amoeba to man. In order to make the picture more or less complete, the Evolutionary Base Line will be given very briefly with a note explaining the advance represented by each form in the series.
The line is traced from the invertebrates to the vertebrates through Amphioxus, a creature which stands lowest in the phylum Chordata. This creature lacks a brain in the accepted sense, all its controls being distributed along the dorsal cord. It differs from other invertebrates in the possession of a pharynx perforated by gill slits which, however, serve to strain food rather than to provide an oxygen supply. Next in this base line it is customary to place the Lamprey, which has its notochord apparently encased in part in bony segments. Lampreys have "nostrils," rudimentary eyes, ears under the skin, and a single nasal pouch. These animals have a brain, but no movable jaw and no fins. Next comes Climatius which, like the former, is quite small but now has a kind of primitive jaw. Then comes Cladoselache, with paired fins, fully developed jaws, jointed and muscled, and with both upper and lower segments free to move. We are then introduced to Crossopterygians. Here we find the presence of bony structures underlying the fins constituting genuine limbs. These are viewed as the forerunners of legs in amphibians. Unlike the animals which preceded, they possessed a simple lung. Associated with these representative creatures in the base line are the Dipnoi, or lung fishes, which are at a similar level of development except that they have a modified mouth construction in which there is an opening from the nasal sac (now a kind of lung) to the inside of the mouth. This enabled the animal for a limited time to dispense with the use of the gills and use oxygen stored in the nasal sac. In conjunction with the development of fins with a bone sub-structure, it became possible for these creatures to make short trips out of the water. It is generally held that, in Devonian times, extended drought dried up many rivers leaving only stagnant pools.
When these became depleted of oxygen, the lung fishes were able to move to new pools. Thus began, supposedly, the conquest of the land.
The most primitive amphibians appear in the Carboniferous Era, namely, the labyrinthodonts, in which appear rudimentary legs with five webbed digits and a more highly developed olfactory sense. Later in the Carboniferous Era, the Cotylosaurs are first discovered. One particular species, the Seymouria, have genuine legs which, however, were very squat and suggest that the possessor was not really at home on land. Nevertheless, the Seymouria produced the first land-type eggs in which the water environment is contained within the egg and surrounded by a "shell."
Up to this point, all living creatures were cold-blooded. So long as they stayed in the water, this was no disadvantage, a water environment being probably the most stable environment conceivable. In very hot weather, the deeper waters remain cool and in sub-zero weather, the ice which forms on the top protects the water beneath from dropping too low. It is generally thought that this accounts for the persistence of many fishes, such as Coelacanths, through millions and millions of years with virtually no change in form. However, when the environment over land areas had been prepared by plant life and the atmosphere had been made fit for animals that breathe air, it was then possible for living creatures to leave their watery home and come up to stay on the dry land. At first these had been forays only, then some of the first pioneers began to lay their eggs on the land, though they and the young returned to the water as a natural habitat. Longer and longer stays were made by such creatures in this new environment, but so long as they were cold-blooded, they were at the mercy of the elements, for when the sun went down or cold weather came, their energy was reduced to a very low level.
There is an early creature occasionally mentioned in the Evolutionary Base Line, the Dmetrodon, that was apparently supplied with a strange sail-like structure along its back supported by a number of "masts." Sometimes it looks as though God took delight in experimenting. It is not certain what purpose these served, but it has been thought that they were heat exchangers, a kind of network of arteries set in a thin membrane stretched out to present the maximum surface area to the sun, thus providing the animal with heat more rapidly than otherwise. Presumably, when cold temperatures came, the reverse process was avoided by a form of vasoconstriction so that deep body heat was not lost to the cool air through the heat exchangers. But no cold-blooded animal can remain active and alert outside of a fairly narrow range of temperature variation. Such creatures could never, therefore, become complete masters of the environment.
At this point, it is customary to follow a sideroad in the Evolutionary Base Line. Warm-blooded animals as a class bear their young alive. The egg, as such, is never "laid." But there was a stage ‹ and representatives still exist ‹ in which the transition was not completely made, as represented by the Duckbilled Platypus and the Spiny Anteater, both of which are egg-laying mammals. These creatures are truly mammals and warm-blooded, yet the young they bear appear first as reptilian eggs. A further stage is represented by the Marsupials. These are pouched animals which, like the Duckbilled Platypus and Spiny Anteater, are not included in the base line; but they are also referred to as transitional forms, because although the egg is never laid in this case, the young are nevertheless hatched "too soon" and have therefore to be returned to a kind of "shell" to complete the full process of embryonic development. They are not included because they are too "late" in the series.
Transitional forms between cold-blooded animals and mammals are sometimes represented by the Therapsids, of which one particular species, the Cynognathus, is customarily singled out. It is not necessary here to detail the reasons why this species is considered transitional, except to mention that it has a number of mammalian features, especially in the mouth region. And although it is coldblooded, it appears to have been highly active -- which most coldblooded land animals are not.
Among the earliest representatives of the Placentals, which bear their young in a fully developed state are Hedgehogs, Ground Shrews, and Tree Shrews. The Evolutionary Base Line is traced through the Tree Shrews for several reasons, one of which is its completely unspecialized form. These little animals enjoy the privilege of being able to sit upright and use prehensile front feet to feed. While they have an exceedingly simple brain, they are highly mobile, with limbs capable of complex movements and a fair range of stereoscopic vision.
On a rung nearer the top of the ladder are placed the Lemurs, in which there is a development of fingernails and well-formed "hands," with opposable thumbs widely separated and separable from the rest of the fingers. They appear to have a wide range of vocalization and their eyes are closer to the front than similar mammals which preceded them. They were quite common in Eocene times. Their facial appearance was somewhat foxlike, a fact which has led some authorities to question whether they should be classed as Primates.
Soon after the appearance of the Lemurs, we find the Tarsioids. These creatures are placed much higher in the scale of evolution and are classed as Primates. Their eyes are turned completely forward, the nose is very short, and the flattening of the face is taken to mean that the sense of smell has become less important and stereoscopic vision has now taken over.
To be continued....
Wednesday, April 09, 2014
Setting of the Stage (the Earth Before Man)
THERE IS
little doubt that the first step in preparing the earth as a habitation for man must have been to clothe it with vegetation as a source of food for the animals which preceded him. The earth's earliest atmosphere was almost certainly not suited for the support of animal life of any kind on land, though the seas could do so. All animals which live on land must have free oxygen as a source of energy. This oxygen can be breathed (or taken in through the skin, as it is in insects) mixed with other gases such as hydrogen or nitrogen, for instance. It appears that in the earth's atmosphere, at the beginning, even after noxious gases had been removed chiefly by loss from the earth's gravitational field, the available oxygen was combined with carbon in the form of carbon dioxide. In order to free the oxygen, plants were created to perform this role by photosynthesis, taking in carbon dioxide and setting the oxygen free in the atmosphere again, converting the carbon into usable form. Since all flesh is grass (1 Peter 1:24) in the sense that all animal life depends upon plant life for energy, plant life had to precede animal life not only to make the atmosphere respirable for them but to supply them with food energy.
But the first plants obviously had to be able to survive without soil, since soil is composed of decayed vegetation. Once vegetation of such a kind had multiplied sufficiently to create humus, then higher forms of plant life more effective as sources of energy for animals ‹ and later for man ‹ could be created and planted. That God should create and plant is not strange, for this is what we are told He did with respect to the Garden of Eden (Genesis 2:8).
The course of events was, then, somewhat as follows. The rock at the surface of the earth was broken down into gravel and sand by the action of waves, wind, gravitational shock (i.e., falling and breaking), and by alternating heat and cold, which would fragment the rock by expansion and contraction. In addition, volcanic action
contributed ash and certain chemicals. In due time such combined forces provided suitable beds for the creation and planting of vegetation capable of growing without soil. As W. Bell Dawson pointed out, to begin the process of clothing the earth, God designed plants that could grow in pure sand; and these gradually made soil for plants of higher classes to grow in. There is, for example, one species of pine which is used extensively in France in the dunes along the coast, for the purpose of preventing them from drifting back over the cultivated fields.
These first plants were reeds, rushes, and ferns, and although they often grew as large as trees, they were not the kind of vegetation which higher forms of animals use as food. They served a dual purpose, however. While they lived, they began to remove from the atmosphere its excess carbon dioxide; and when they died, they created a humus which when it had accumulated sufficiently provided the bed into which higher forms of plant life were introduced by creation. Lichens also enter this picture as fundamental to all that followed. "Lichens have no need for soil, but, preparing it, they lay the cornerstone for flowers and trees. They are the plant world's pioneers, bringing life where none existed." When the time was fully come that animals should move out of the sea on to the dry land, there was both air fit for them to breathe and food suitable for them to eat.
George Wald, Professor of Biology at Harvard, speaks of the preparation of the atmosphere by plant life in the following way:
Wald spoke of "inventing" a new way to acquire energy far more efficient than the methods by which plants acquire it. The word "invent" is inappropriate since it attributes to inanimate things a consciousness of purpose which they surely do not have. But his remarks serve to point out that the liberation of free oxygen for cellular respiration allowed for the introduction of living forms with immensely increased energy potential. The lowest, and thus presumably the oldest, deposits of minerals are found in non-oxidized form, which seems to demonstrate the initial absence of free oxygen. It is evident, therefore, that animal life could not have existed until the plants had transformed the atmosphere.
This step thus opened the way for the introduction of creatures which were far less tied to their environment, one further step in the unfolding of God's purposes in the ultimate creation of man. As Wald put it: (
Everything is orderly and purposeful, there is nothing accidental about the order in which forms of life appear from amoeba to man. Next time we'll take up the discussion of
little doubt that the first step in preparing the earth as a habitation for man must have been to clothe it with vegetation as a source of food for the animals which preceded him. The earth's earliest atmosphere was almost certainly not suited for the support of animal life of any kind on land, though the seas could do so. All animals which live on land must have free oxygen as a source of energy. This oxygen can be breathed (or taken in through the skin, as it is in insects) mixed with other gases such as hydrogen or nitrogen, for instance. It appears that in the earth's atmosphere, at the beginning, even after noxious gases had been removed chiefly by loss from the earth's gravitational field, the available oxygen was combined with carbon in the form of carbon dioxide. In order to free the oxygen, plants were created to perform this role by photosynthesis, taking in carbon dioxide and setting the oxygen free in the atmosphere again, converting the carbon into usable form. Since all flesh is grass (1 Peter 1:24) in the sense that all animal life depends upon plant life for energy, plant life had to precede animal life not only to make the atmosphere respirable for them but to supply them with food energy.
But the first plants obviously had to be able to survive without soil, since soil is composed of decayed vegetation. Once vegetation of such a kind had multiplied sufficiently to create humus, then higher forms of plant life more effective as sources of energy for animals ‹ and later for man ‹ could be created and planted. That God should create and plant is not strange, for this is what we are told He did with respect to the Garden of Eden (Genesis 2:8).
The course of events was, then, somewhat as follows. The rock at the surface of the earth was broken down into gravel and sand by the action of waves, wind, gravitational shock (i.e., falling and breaking), and by alternating heat and cold, which would fragment the rock by expansion and contraction. In addition, volcanic action
contributed ash and certain chemicals. In due time such combined forces provided suitable beds for the creation and planting of vegetation capable of growing without soil. As W. Bell Dawson pointed out, to begin the process of clothing the earth, God designed plants that could grow in pure sand; and these gradually made soil for plants of higher classes to grow in. There is, for example, one species of pine which is used extensively in France in the dunes along the coast, for the purpose of preventing them from drifting back over the cultivated fields.
These first plants were reeds, rushes, and ferns, and although they often grew as large as trees, they were not the kind of vegetation which higher forms of animals use as food. They served a dual purpose, however. While they lived, they began to remove from the atmosphere its excess carbon dioxide; and when they died, they created a humus which when it had accumulated sufficiently provided the bed into which higher forms of plant life were introduced by creation. Lichens also enter this picture as fundamental to all that followed. "Lichens have no need for soil, but, preparing it, they lay the cornerstone for flowers and trees. They are the plant world's pioneers, bringing life where none existed." When the time was fully come that animals should move out of the sea on to the dry land, there was both air fit for them to breathe and food suitable for them to eat.
George Wald, Professor of Biology at Harvard, speaks of the preparation of the atmosphere by plant life in the following way:
The atmosphere of our planet seems to have contained no (free) oxygen until organisms placed it there by the process of plant photosynthesis. . . .
Once this was available organisms could invent a new way to acquire energy, many times as efficient. . . This is the process of cold combustion called respiration.
Wald spoke of "inventing" a new way to acquire energy far more efficient than the methods by which plants acquire it. The word "invent" is inappropriate since it attributes to inanimate things a consciousness of purpose which they surely do not have. But his remarks serve to point out that the liberation of free oxygen for cellular respiration allowed for the introduction of living forms with immensely increased energy potential. The lowest, and thus presumably the oldest, deposits of minerals are found in non-oxidized form, which seems to demonstrate the initial absence of free oxygen. It is evident, therefore, that animal life could not have existed until the plants had transformed the atmosphere.
This step thus opened the way for the introduction of creatures which were far less tied to their environment, one further step in the unfolding of God's purposes in the ultimate creation of man. As Wald put it: (
Photosynthesis made organisms self-sustaining; coupled with respiration, it provided a surplus (of energy). To use an economic analogy, photosynthesis brought life to the subsistence level, respiration provided it with capital.But this is not all. The new atmosphere thus generated had an equally important function of another kind:
The entry of oxygen into the atmosphere also liberated organisms in another sense. The sun's radiation contains ultraviolet components which no living cell can tolerate. We are sometimes told that if this radiation were to reach the earth's surface, life would cease. That is not quite true. Water absorbs ultraviolet radiation very effectively, and one must conclude that as long as these rays penetrated in quantity to the surface of the earth, life had to remain under water.These stages of preparation reinforce the concept of purpose, because they indicate the timed introduction of the requisite elements in the economy of Nature at each step as required -- and very frequently without predecessors. The appearance of lichens, for example, looks much more like deliberate creation than the outcome of pure chance. Similarly, later on, lungs seemed to be in the making at the same time that the atmosphere was being prepared for creatures that could make full use of such structures, a circumstance which again looks much more like planning than the operation of pure chance.
With the appearance of oxygen, however, a layer of ozone formed high in the atmosphere and absorbed this radiation. Now organisms could for the first time emerge from the water and begin to populate the earth and the air. Oxygen provided not only the means of obtaining adequate energy for evolution, but the protective blanket of ozone which alone made possible terrestrial life.
Everything is orderly and purposeful, there is nothing accidental about the order in which forms of life appear from amoeba to man. Next time we'll take up the discussion of
To be continued . . .
Wednesday, March 19, 2014
the Concept of Teleology
ALFRED KUHN pointed out that modern objections to the inclusion of the concept of purpose to account for any phenomenon in Nature are traceable to Emmanuel Kant's "Critique of Teleological Judgment." ) Kant held that such a concept really explains nothing, because it makes the "end," or objective, the cause. The end becomes the beginning. The argument is circular and therefore without force.
However, not all agree. Indeed, in recent years the older teleological view is regaining favour, especially among those whose main concern is with the origin and the nature of life, where behaviour at a molecular and cellular level, as well as at the whole animal level, is increasingly difficult to explain in purely mechanistic terms. Thus Peter T. Mora of the National Institute of Health, Bethesda, Maryland ‹ during the discussion which followed a paper entitled "The Folly of Probability,"
which he presented at a conference on the general subject of the origin of prebiological systems ‹ argued that the present insistence among biochemists that the concept of purpose must be rigidly excluded from all research into the origin and nature of life is proving just as defeating and unhealthy as the medieval insistence was that no other concept was acceptable. It is interesting to note that Dr. Mora's paper, according to the chairman (J.D. Bernal of England), raised "the most fundamental questions of the theory of the origin of life that have been raised at this conference, or as far as I know elsewhere." Mora's conclusion is that "a certain type of teleological approach must be pertinent to the study of living systems," and therefore we ought to "dare to ask whether there is something special in the living which cannot be treated by physics as we know it. . . ."
This is in marked contrast to the views of an older generation. Leo Berg in his Homogenesis observed: "The history of science has taught us that vitalism, as a hypothesis, is valueless, it has in nowise aided us in making any progress in the interpretation of facts." Later he said:
It is true that the teleological explanation may be a lazy man's way out of an intractable problem. But it may also be the worshipful man's insight. The difficulty is to find the balance. But one does not find the balance by simply denying the alternative route to understanding. Sir Alister Hardy said in his book The Living Stream, that while we may regard the fabric of an organism as a mechanical configuration, "I would not for the world be thought to believe that this is the only story which life and her children have to tell. One does not come by studying living things for a lifetime to suppose that physics and chemistry can account for them all." And Susanne Langer, with her characteristic eloquence and insight, pointed out:
However, not all agree. Indeed, in recent years the older teleological view is regaining favour, especially among those whose main concern is with the origin and the nature of life, where behaviour at a molecular and cellular level, as well as at the whole animal level, is increasingly difficult to explain in purely mechanistic terms. Thus Peter T. Mora of the National Institute of Health, Bethesda, Maryland ‹ during the discussion which followed a paper entitled "The Folly of Probability,"
which he presented at a conference on the general subject of the origin of prebiological systems ‹ argued that the present insistence among biochemists that the concept of purpose must be rigidly excluded from all research into the origin and nature of life is proving just as defeating and unhealthy as the medieval insistence was that no other concept was acceptable. It is interesting to note that Dr. Mora's paper, according to the chairman (J.D. Bernal of England), raised "the most fundamental questions of the theory of the origin of life that have been raised at this conference, or as far as I know elsewhere." Mora's conclusion is that "a certain type of teleological approach must be pertinent to the study of living systems," and therefore we ought to "dare to ask whether there is something special in the living which cannot be treated by physics as we know it. . . ."
This is in marked contrast to the views of an older generation. Leo Berg in his Homogenesis observed: "The history of science has taught us that vitalism, as a hypothesis, is valueless, it has in nowise aided us in making any progress in the interpretation of facts." Later he said:
We are enabled to work fruitfully in the field of natural science only by the aid of forces recognized in physics, and every naturalist should endeavor to interpret nature by mechanistic means. . . .This could be true if the only object of research is the collection of measurable data for the purposes of prediction, if the only tools of research are those that measure and weigh, and the only way of obtaining a hearing among one's peers is to adopt an entirely mechanistic approach or else find oneself without a voice and a hearing.
It is true that the teleological explanation may be a lazy man's way out of an intractable problem. But it may also be the worshipful man's insight. The difficulty is to find the balance. But one does not find the balance by simply denying the alternative route to understanding. Sir Alister Hardy said in his book The Living Stream, that while we may regard the fabric of an organism as a mechanical configuration, "I would not for the world be thought to believe that this is the only story which life and her children have to tell. One does not come by studying living things for a lifetime to suppose that physics and chemistry can account for them all." And Susanne Langer, with her characteristic eloquence and insight, pointed out:
Since the assumption of a Divine Creator, who might exercise the required foresight and ingenuity, is proscribed in the scientific sphere, the analogy of the industrial plant can be carried out only with a replacement in the managerial and planning departments; and this is commonly made surreptitiously by a literary trick of using what purports to be a mere figure of speech ‹ the introduction of "Nature" or "Evolution" as the agent who supplies the blueprints and materials and guides the attainment of her (instead of His) purposes. This ready evasion of a difficulty, which really shows up the weakness of the machine model, has become the stock in tradeSubsequently, he noted that there is a frank return to teleology by such outstanding workers as H. Krebs, and more recently A. V.
not only of science writers, but of excellent, authoritative scientists writing on problems of adaptation, organic integration and evolutionary tendencies.
Langer gives one example: A. von Szent-Gyorgyi in his book Oxydation and Fermentation wrote: "Nature discovered oxydation by molecular oxygen. . . ." And again, "We usually find that the way Nature reaches its purpose is the only possible way, and yet, in spite of its simplicity, the most admirably ingenious way." Surely these things could only be said of a personal agent, and who else could this possibly be but God Himself? Langer says, "The factory manager is left nameless."
Andre Schlemmer pointed out long ago that life behaves so unlike a machine in so many ways, that the mechanistic approach simply has to be abandoned again and again. Thus the body has very un-machine-like powers to heal itself, to repair and renew its parts, to make compensatory adjustments in order to insure the same work output. And "the most materialistic biologist cannot refrain from falling into teleological language as soon as he turns to explain the process." He is simply forced to personify the agent who oversees it.
Max Kleiber, an internationally renowned physiologist, brought up in the school of Claude Bernard, objected strongly to any such course of action by a scientist. Science must rid itself of any appeal to a "personal" agency in the works. Thus he said:
In an attempt to clear science of theology, the postulate that man is a machine is a rather tricky analogy, because an essential characteristic of a machine is that it is planned for a purpose, which implies a designer. . . . The study of man as a machine leads to teleology, and that leads naturally to the question of the mind of the designer of man. This mind must work in a way similar to that of the human mind, if we are to understand its planning; we understand the planning of the machine because the designing engineer thinks as we think. So we are back to theology.He then observed that as an evasion of this rationale, some atheistic teleologists deified nature itself! But he asked, "Can a biologist learn to understand what the inventor of a fish or a man had in mind when he designed these creatures?" How blind can one be, indeed!
Hill, both Nobel Laureates. The latter referred to "innumerable examples in both animal and plant life of what can only be described as evidences of superb engineering ‹ which, of course, invites acknowledgment of a superb 'Engineer'." Kleiber would have none of this. He said, "Instead of accepting an analogy between a creator of organisms and a designer of machines and hunting for divine blueprints, the Darwinistically oriented physiologist is stimulated to search for causes, and even if he does not completely succeed he usually finds a lot of what is interesting on his way." This seems to me a rather unsatisfactory motivation for the dedication of one's life to research. And if Krebs and Hill, and a growing number of other workers in the life sciences, are any indication, it is a futile approach as well.To be continued . . .
But Kleiber was, it seems to me, fighting a losing battle, especially when dealing with the extraordinary abilities of the animal body to prepare itself for a role that is yet future. The embryologist sees this particularly -- though he may be reluctant to say much about it because of the pressure of scientific opinion to the contrary. Sir Charles Sherrington expresses his wonder at it all, but is clearly not willing to acknowledge the existence of a divine Designer behind it. But his style of writing contrasts notably with that of, for example, G. G. Simpson writing on the same subject. Simpson exemplifies a peculiar blindness in a remarkable way. Thus in a paper entitled "The Problem of Plan and Purpose in Nature" (emphasis mine), he wrote:
An eye, an ear, or a hand is also a complex mechanism serving a particular function. It, too, looks as if it had been made for a purpose. This appearance of purposefulness is pervading in nature, in the general structure of animals and plants, in the mechanisms of their various organs, and in the give and take of their relationships with each other.
It is indeed.
Darwin said he never contemplated the design of the eye without a tremor. And Sir Charles Bell in 1832 wrote his Bridgewater Treatise, The Hand: Its Mechanism and Vital Endowments as Evincing Design, almost as an act of worship. Such was the spirit of the time which moved some men to praise and others to tremble. Other later men of equal stature with Bell, like Sir Charles Sherrington, acknowledged their unstinting admiration of the eye as an
optical instrument and yet could no longer see it as evidence of design by the Creator.
One may compare Simpson's treatment of the eye in his Meaning of Evolution (pp.169‹175) and be impressed with his knowledge of the data on eyes in general. But one also senses the coldness, and one might almost say the disinterest of the writer, in the basic questions that such an organ raises. If one reads, by contrast, Sherrington's treatment of the same subject in his Man on His Nature (pp.105‹l09), one begins to capture something of wonder in the author's mind. How sad, then, to find that he too was blind to the possibility that the designer was a Person, personally approachable and personally rejoicing in His own creations.
One writer of comparatively recent times, whose work is always a delight to read ‹ perhaps because of his willingness to admit the fact of purpose ‹ was F. Wood Jones of England. In his Trends of Life, he stated the present position very clearly when he said:
Against the tyranny of modern orthodox views on teleology there is no reason whatever why we should not rebel, for orthodoxy in this case, is not supported by scientific facts, but rests for the most part on prejudices inherited from the "intransigent materialism of the nineteenth century."It is true. Prejudice, not scientific objectivity, has been the real reason for the rigid exclusion of the concept of design and purpose in accounting for natural phenomena. It certainly did not prevent Joseph Priestley in his research in chemistry, nor Sir Charles Bell in his research in physiology. Nor did Newton's faith prevent him from formulating his Principia, acknowledged to be one of the most extraordinary creations by the human mind in mathematics. There is really no sound reason to exclude the possibility of a Personal Creator superintending His own created order, though it may humble man a little by making him dependent upon revelation wherever his own limited means of exploration of the natural world prove inadequate.
Friday, February 28, 2014
Evolution- the study of origins (Part 5)
Water is the most universally effective chemical solvent known, dissolving more substances than any other liquid, though being itself exceedingly stable chemically. It thus provides the fluid medium in which extremely slow chemical reactions may proceed rapidly. It constitutes the fluid medium in the body which makes the body a functioning chemical plant of high efficiency. Water also has almost the highest heat capacity of any known substance and therefore is probably the ideal stabilizer of the temperature of the planet, absorbing enormous amounts of heat without itself becoming too warm for life and then surrendering that heat without itself becoming too cold. Its unusual properties in all three states -- solid (ice), liquid, or gaseous (vapour) ‹ within the temperature ranges common to the earth make it tremendously important as a mechanical agent in modifying the earth's surface, weathering the rocks and creating a bed for the first plants, and allowing for its own re-circulation by evaporating into cloud formations and then being condensed and precipitated. Its ability to absorb large quantities of oxygen at comparatively low temperatures guarantees survival of living organisms in oceans and lakes. Its exceptional property of expanding slightly just above the freezing point allows it to form a protective layer of ice that floats on the surface and prevents large bodies of water from freezing solid and destroying marine life.
Meanwhile, the earth has a proper relative proportion of land and water surface in order that the land may be neither parched through insufficient precipitation nor turned into a swamp through excess. The topography of the land is such that it assists in the process of watering the earth by causing turbulence in air currents which pass over it, thus bringing about the breakup of cloud formations.
(6) The existence of the moon is also of fundamental importance tothe earth. As far as is known, it is the largest satellite relative to the size of its parent body. From this point of view it is, in fact, huge. The moon has sufficient mass to cause tides, and tides are of great importance in keeping the oceans fresh. The possession of a moon of such a size by our earth is of importance in more than one way to life as we know it. What currents do in vitalizing rivers, tides do for the oceans.
All these coincidences add up to an impressive testimony to the uniqueness of the earth as a theatre for the unfolding of God's plan. In his book Man on His Nature, Sir Charles Sherrington remarked:
Dean H. Kenyon and Gary Steinman, in their book Biochemical Predestination, would go one step further and argue that the raw materials for life were created in such a form that life must have been predestined by them. They put it this way: "Biochemical Predestination means that the limits beyond which evolutionary processes could not stray, would be determined largely by the properties inherent in the evolving bodies as preset by the (raw) materials from which the (finished) materials were fabricated."
We are often told that the chances of life on other planets like the earth are very considerable, and there is no need to suppose that the existence of life here is really so exceptional. I think the total situation is more complex than the public has been led to believe. In a paper entitled, "Some Cosmic Aspects of Evolution," which G. G. Simpson contributed to a symposium held in Europe in 1968, he dealt with some aspects of the possibility of life elsewhere in the universe and concluded with the following remarks:
In my opinion those chances are effectively nil for the mere one hundred million planets of Shapley's minimum or even for Hoyle's less reasonable billions of billions.
And this touches one other point. We are making an assumption that the universe was created a very long time ago. It is quite conceivable that God could have created everything instantaneously and set the stage for man in a moment. Yet this would have two effects: First, it would have prevented us from seeing how wise, methodical, and orderly is God's work. The suddenness of instantaneous creation is frightening rather than reassuring and, as a rule, God has only adopted this method when He desired to make a special impression. It is not His normal way. Moreover, "taking time" implies a certain determination, forethought, and unchangeableness of purpose, as though the end result was something greatly to be desired how ever long it took to achieve. It seems to have taken a long time to prepare the earth for man, and so long as we believe it was a preparation for man, we can derive considerable assurance and
comfort from the knowledge that God was prepared to work so patiently. Yet from His point of view, there may have been no delay involved. Le Comte du Nouy made this remark:
Unfortunately, for a little over one hundred years, since Lyell and Darwin's time, man has not been willing to see the whole process as purposeful with respect to himself. The insights of previous generations of naturalists have been, and largely continue to be, laid aside as inappropriate to the naturalistic world view. But the categorical denial of teleological explanations, a denial which at first seemed so stimulating to our understanding of the natural order, is now beginning to prove to be a barrier to further advances in understanding, and there is a new wind blowing.
To be continued . . .
Meanwhile, the earth has a proper relative proportion of land and water surface in order that the land may be neither parched through insufficient precipitation nor turned into a swamp through excess. The topography of the land is such that it assists in the process of watering the earth by causing turbulence in air currents which pass over it, thus bringing about the breakup of cloud formations.
(6) The existence of the moon is also of fundamental importance tothe earth. As far as is known, it is the largest satellite relative to the size of its parent body. From this point of view it is, in fact, huge. The moon has sufficient mass to cause tides, and tides are of great importance in keeping the oceans fresh. The possession of a moon of such a size by our earth is of importance in more than one way to life as we know it. What currents do in vitalizing rivers, tides do for the oceans.
All these coincidences add up to an impressive testimony to the uniqueness of the earth as a theatre for the unfolding of God's plan. In his book Man on His Nature, Sir Charles Sherrington remarked:
A great American physiologist, Lawrence Henderson, has set forth the particularity of the physical and chemical conditions whose occurrence on the face of the earth render possible the existence of the systems we call living. Certain anomalous properties of water in conjunction with universal powers and space-relations of the carbon atom, along with exceptional conditions of radiation and temperature, are shown to form a sort of conspiracy of circumstance allowing life to be, both here and now.
Dean H. Kenyon and Gary Steinman, in their book Biochemical Predestination, would go one step further and argue that the raw materials for life were created in such a form that life must have been predestined by them. They put it this way: "Biochemical Predestination means that the limits beyond which evolutionary processes could not stray, would be determined largely by the properties inherent in the evolving bodies as preset by the (raw) materials from which the (finished) materials were fabricated."
We are often told that the chances of life on other planets like the earth are very considerable, and there is no need to suppose that the existence of life here is really so exceptional. I think the total situation is more complex than the public has been led to believe. In a paper entitled, "Some Cosmic Aspects of Evolution," which G. G. Simpson contributed to a symposium held in Europe in 1968, he dealt with some aspects of the possibility of life elsewhere in the universe and concluded with the following remarks:
The chances that anything like man, or for that matter like any other terrestrial species except perhaps the most primitive, exists elsewhere in the universe are, I think, the same as the chances that any other planet has had exactly the same history as earth -- and as its inhabitants -- in every essential detail for two billion years and more.
I therefore earnestly doubt whether there are any manlike beings waiting to greet us anywhere in the universe. The opposite opinion, even though it has been advanced by some eminent and sensible men, seems to me to underestimate either the complexity or the rigidity of historical causation.Our earth therefore may be somewhat more significant than we might suppose, even though astronomers have shown that it is such a tiny speck of material in an inconceivably vast universe. The question arises, can such a tiny speck, looked at from this point of view, be really so important? The answer, I think, may be found this way: There are two alternatives. One would be to make the earth much larger relative to the universe. And the other would be to make the universe much smaller relative to the earth. As we have seen, the first alternative is out of the question; the size of the earth cannot be changed very much. Then what of the latter alternative? What would happen if the universe were made smaller? Is it not true that in due time we should pierce through space until we have found its boundaries? Then suddenly it would not seem so big after all. At first this might not matter very much. But in the end and in a subtle way, when we found we could comprehend the whole of it, our view of the Creator would begin to contract and He would seem to become smaller as our exploration became more complete. In a way, man's greatness is sensed by the magnitude of his achievement, and the immensity of the universe -- for the Christian -- adds not a little to our sense of awe and our worship of the Creator. If it is true that the universe is expanding, there is little need to fear that we can ever catch up to, or overtake the greatness of God.
And this touches one other point. We are making an assumption that the universe was created a very long time ago. It is quite conceivable that God could have created everything instantaneously and set the stage for man in a moment. Yet this would have two effects: First, it would have prevented us from seeing how wise, methodical, and orderly is God's work. The suddenness of instantaneous creation is frightening rather than reassuring and, as a rule, God has only adopted this method when He desired to make a special impression. It is not His normal way. Moreover, "taking time" implies a certain determination, forethought, and unchangeableness of purpose, as though the end result was something greatly to be desired how ever long it took to achieve. It seems to have taken a long time to prepare the earth for man, and so long as we believe it was a preparation for man, we can derive considerable assurance and
To an imaginary being, with a life span of ten thousand million years evolution would seem very rapid. To God, whom we cannot even conceive in relation to time, it may well have been instantaneous.There is no doubt, of course, that God could have created the world instantaneously, although this would have involved the making of many things in such a form that they would appear to have an age which they did not, in fact, actually have ‹ trees with tree rings that did not signify age, humus which was not constituted of decayed vegetation, and so forth. Scripture shows that this kind of "creation with a history" has often occurred in a miraculous way whenever it was absolutely necessary. Thus Moses' rod became a serpent (Exodus 4:2‹4) which was probably of comparable length, and therefore of a specific age, since serpents grow with age continuously. When the Lord restored Malchus' ear (Luke 22:51), it was the ear of a man, appropriate to his age even though it had certainly been created instantaneously. There are many such illustrations in Scripture. Undoubtedly the Lord could have accelerated the preparation of the earth for man in the same way, but evidently a better purpose was served by working in a manner more in keeping with human experience in order that man could, if he would, see that it was all done specifically in preparation for his own coming.
Unfortunately, for a little over one hundred years, since Lyell and Darwin's time, man has not been willing to see the whole process as purposeful with respect to himself. The insights of previous generations of naturalists have been, and largely continue to be, laid aside as inappropriate to the naturalistic world view. But the categorical denial of teleological explanations, a denial which at first seemed so stimulating to our understanding of the natural order, is now beginning to prove to be a barrier to further advances in understanding, and there is a new wind blowing.
To be continued . . .
Tuesday, February 25, 2014
Part 4 the Earth as regarding Evolution
IT IS a curious thing that so long as man was viewed as the centre of the universe because of his unique relationship to God, the earth which is his home automatically achieved its special status by association, and very little thought was given to its peculiar fitness in performing this function. It was only after man had been dethroned and the geocentric concept of the universe had been abandoned, that man suddenly began to realize what a unique body the earth really is.
The uniqueness of the earth as a setting for life is indeed quite extraordinary and the fact is very widely recognized among scientists who nevertheless view it as a purely accidental circumstance. The kind of uniqueness here in view involves a number of factors: (1) its size, (2) its rate of revolution, (3) its mean distance from the sun, (4) the variations in its distance as it circles the sun, (5) the constitution of its surface, and (6) its satellite, the moon.
(1) The size of the earth determines the constitution of its atmosphere, and the constitution of its atmosphere determines the nature of the living forms upon it. (6)
If it were much larger, it would have retained a large percentage of gases inimical to life. If it were much smaller, its gravitational forces would have been insufficient to retain virtually any atmosphere at all. The smaller planets with smaller gravitational fields lose a large proportion of their lighter elements during the cooling process. The larger planets retain most of their original atmosphere. Actual measurements show that although the weight of Jupiter is only 317 times that of the earth, so great is the amount of atmospheric strata around it that its volume appears to be 1300 times greater than that of the earth. The planet Mercury, on the other hand, has a mass approximately one twenty-third that of the earth and is known to have no appreciable atmosphere surrounding it, its gravitational field being too weak to retain nitrogen, oxygen, and water vapour.
The earth has, as a result, just sufficient mass that it is able to hold around itself a blanket of gases which both supports life and shields it from lethal rays of the sun. Its size is such that poisonous gases which formed as the earth cooled were not held in the atmosphere but escaped into space. The carbon dioxide, which was held, ultimately supported luxuriant vegetation, which in turn purified it for animal life by setting oxygen free through photosynthesis. Gases, like all other things, have mass, some being heavier than others. It so happens that the gases unsuitable for life were light enough and the earth's gravitational pull small enough that they were lost into space and thereby eliminated.
(2) The rate of revolution of the earth is just right for the continuous renewal of the atmosphere for animal life. Nothing gets too cold or too hot over most of its area, and plants have just sufficient times of light and of darkness to perform their function of regenerating the air (since the unique stability of carbon dioxide depends upon alternating light and darkness)
.
(3) The distance from the sun determines the mean temperature of the atmosphere and the earth. The pliable materials of which living tissue is composed are made up of chains of molecules which retain their physical characteristics within a comparatively narrow range of temperature variation. It appears that apart from the very exceptional properties of carbon in forming these long chainlike molecules, such structures as ourselves and all other pliant forms would not be possible at all. It is only in a very restricted range of temperature that these carbon compounds are stable. If the temperature becomes too cold, these chains become inflexible, and if the temperature becomes too high, they lose their bonds and disintegrate. The range of temperature within which living flesh can continue without artificial protection is quite small relative to the ranges of temperature which may exist on a body in space.
(4) The seasonal variations which take place throughout the year, due to the 23° axial tilt of the earth, are very important for the continuance of human life. Were it not for these changes, micro-organisms which cause diseases and which are favoured by certain environmental conditions, would multiply so extensively that the
human race might very well suffer extinction because of them. Man is not the only animal to suffer on this account. Consider what would happen to the mosquito population if the conditions ideal for their multiplication were to persist throughout the year all over the globe. Surgeon-General C. A. Gordon pointed out that not only does the persistence of a particular temperature and humidity have to be taken into account here, but even the length of day. The length of day, of course, is governed by the rate of revolution of the earth about its axis. In his paper, Gordon gave a chart showing the distribution throughout one year of some of the major diseases caused by these micro-organisms. Were the conditions favouring any one of the disease micro-organisms maintained throughout the year, the consequences would probably be disastrous for man.
(5) The surface of the earth is part water, part dry land, in a ratio of approximately 3 to 1. The uniqueness of water has been pointed out by countless authorities so that the existence of water in a fluid state is itself fundamental to the continuance of life. On this point Harold Blum makes the following observations:
Water makes up perhaps 80 to 90% of all living organisms, and may be regarded as their principal environmental component, since even forms living in air maintain an aqueous internal environment in one way or another. Most of the water on the earth is in the liquid state, but it is also of importance as an environmental factor when in the vapor state and even as a solid.Blum then elaborates upon these properties. His elaboration leaves one filled with wonder at the power and wisdom of God in creating such a medium. But this medium requires a quite specific environment for its continued usefulness. That is to say, it is useful in a unique way -- in a unique environment. Blum sums this up by saying:
Water seems admirably suited for the major role it plays in maintaining a relatively constant temperature for the earth's surface, a matter of paramount importance to living organisms, which can serve only within a very restricted range of temperature. It owes this aspect of its fitness to several properties.
So fitness partakes of the nature of uniqueness, the uniqueness of the earth as an abode of life is a matter that strikes one more forcibly the more he tries to break out of the circle. Not only is the earth as it is, but it has reached that state through an evolutionary process, each step of which has been dependent upon the one preceding it.The stage upon which living systems bowed their debut was set by all the preceding events in the history of the earth ‹ or, for that matter, of the Universe. These events placed important restrictions upon the nature of life and its evolution.To be continued . . .
Life, it seems, did not arise and evolve as a system free to vary in any direction whatever; but as a system upon which great restrictions were placed, some of them even before the earth came into existence.
Harold Blum concludes his chapter "Fitness of the Environment" with these words, "This aspect of fitness is not, then, universal, but exists only in relation to the planet Earth, or to planets that are very nearly like the Earth.''
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