The account to which we now come is an example of science writing in which free use is made of the words in the General Science List and of words which are international in science. The words of the second group are put in italics with * after them, and may be taken as not needing to be made clear to anyone with any knowledge of science. Those in the first group which come into these pages (and are marked out by being put between single quotes) are listed after this with their senses in Basic, in the order in which they come in.
|rock.||(great natural mass of) stone or stone-like material; any special sort of solid material present in great amounts in the earth|
|shell.||hard outer cover of certain sea and land animals.|
|deposit.||solid material put down, specially by water, on some other body; depositing-the process of putting down material in this way.|
|solution.||substance, specially a liquid, having another substance (solid, liquid, or gas) so mixed with it that .there is a regular distribution of the molecules of the one among those of the other, and the mixed substance gives no sign of the separate existence of the two; the condition of being so mixed in a liquid and so on.|
|age.||time for which anything has been in existence, how old it is; great stretch of time, division of history.|
|generation.||the act or process of producing offspring; the group of offspring produced by a given plant, animal, or group; one stage or level in a family-tree.|
|enviroment.||place and other outside conditions in which a living thing has its existence and development.|
|mean.||condition, quality and so on equally far from two opposites, coming between them, specially as taken to be representative of what is most normal, generally come across.|
Charles Lyell's Principles of Geology
The idea of 'Evolution,' or the development of different sorts of things from simpler forms by natural processes, was not new in the year 1859.1 Not only had such ideas come to the Greeks (probably from Egypt); but a general uncertain belief that some such process was responsible for the different forms of the living things on Earth had been 'in the air' for 70 or 80 years. And, what is more important, a theory of the evolution of the 'rocks' of the Earth had taken a strong position with the printing of Charles Lyell's Principles of Geology in 1830-33.
To make a connection with the past, we will go back to the theories of Buffon, if only because they are signs and records pointing to one special tendency. They put the authority of the Bible on one side: they gave an idea of the Earth's past history, in comparison with which all the records of Man's past were like notes on the last two or three pages of a great shut book, at the broken edges of which a sign might here and there be seen. It was in this way that John Michell (1760) saw the rock-beds of England; though no reading of the signs, and no decision about the true order of the leaves, was possible till the time of William Smith (1769-1839).
At quite an early stage the Italian experts Vallisneri (1721), Marsilli, and Moro (1740) had seen that fossils were grouped in certain rocks; and in his expansion of Moro's theories, Generelli (1749) had made it his design to give reasons for the structure of the Earth, without unnatural changes, without fictions, without hypothesis.2 His general theory, like that of Hooke before him, was that the rocks had been formed under the sea, and lifted by earth-shocks. Donati had seen how 'shells' were being put down in the Adriatic in groups like those seen by Spada, Schiavo, and Marsilli in the rocks; and the fact that earth-shocks were not uncommon in Italy, and that a new island had been sent up by one in 1707 made this theory of sudden change seem very probable.
is Earth had been made by God?
Attempts had been made to put the rocks into groups in the order in which they were formed. Lehmann in Germany (1756) and Arduino some three years later in Italy had made three divisions: (i) the first, or 'Primary' Rocks, coming from the Creation3 (and so with no fossils); (ii) the second or 'Secondary' Rocks produced by destruction of these; and (iii) the third, or Tertiary Rocks formed by later 'depositing,' possibly or probably by the Flood.4 Theories not unlike those of Moro were put forward in Germany by Gesner (1758) and Raspe (1763), after the groupings had been made clearer by Fuchsel (1762, 1773). But almost all these workers were limited in their discoveries by two chief troubles: the need to get their theories into agreement with the Bible-story; and the very limited distribution of ideas at this time.
Had this not been so, the good work of Guettard (1715-86) and Desmarest (1725-1815) in France might have made a great change; though the wall of authority was still very strong even after Lyell's great work. On this point, the trouble was put very clearly by Gesner in 1758, though it was not very different from what had kept Steno's mind back a hundred years earlier.
It was clear from measurings of the rate of depositing in the Baltic that at least 80,000 years would be necessary for forming such mountains as the Apennines. But the range of time given by working from the Bible was not more than one-twentieth of this. There was no doubt that the Bible was right; so that it was clear that the Earth had been made by God, using natural forces, possibly, but certainly using them in ways which were no longer natural.
What was needed was a general uniting of knowledge into an ordered structure of theory, taking in all the facts. But when a great mind came to do this, the effect was to keep back the growth of the science for 50 years of bitter argument. Abraham Gottlob Werner (1749-1817) was a great teacher with a surprising power over the minds of other men, and a very German love of system. He made his name by a well worked-out grouping of minerals' and by discoveries in Crystallography which have every right to a respected memory. But in his theory of the Earth he went from a limited knowledge of Saxony and Hesse to the widest and most general views (dependent on Leibnitz and Lehmann in some degree) with little or no knowledge of the structure of any other part of Europe.
His greatest error was to take over from the past the idea of the Great Deep (or Universal* Ocean*) by which the earth had been covered at the Creation, and say that the earliest rocks were chemically deposited from it at a time when there were no living things. Rocks had been formed, he said, all over the Earth at the same time, and under like conditions, and there had been no far-ranging violent changes from the time of the Flood.
Now in France, the work of Guettard and Desmarest had made it quite certain that volcanoes*, commonly taken to be fire-mountains, had sent liquid rock over, through, and between water-formed beds, in a way which made any theory of chemical depositing from 'solution' quite impossible. And these rocks were very like some of the 'primaries' in a number of ways. Werner, however, had only seen the basalts* round Freiburg; flat tables on the mountain-tops which had the same form as the common strata* or parallel beds formed by water. So though Desmarest had been able to make comparisons with rocks in other places, and to see that the Freiburg basalts, like those of Staffa, were 'igneous' rock, that is, rock formed at great heat, this had no authority with the "Neptunian School," as it was named: after Neptune, the Roman sea-god.
Building of future rocks with destruction of past earths
In the year 1788 James Hutton (1726-1797) first made public his theory, later printed with additions (1795) and given a wider public in the more pleasing prose of his friend Playfair's Illustrations of the Huttonian Theory (1802). The uniting purpose of these was to give an account of the earth's structure based only on observations of fact; that is to say, on reasoning from changes of the sort still going on. Hutton was attempting to do for the structure of the Earth what Laplace had made complete for the motions of the stars: to give a reading of the Past and Future based only on reasoning from present observation. Great changes, said Hutton, had gone on very slowly in very great time.
The earliest rocks were igneous, the later ones chiefly water-formed; but from time to time there had been great outbursts of heated rock (producing the basalts and the Scots granites*) which had been forced through earlier strata. Everywhere there was to be seen the destruction of past earths, from which, when the broken bits were taken to the sea by rivers, the building of future rocks would be started, till the sea-beds were lifted, and a new land took the place of the old; then that again would go through the same unending process of change and destruction under the rains and snows of a far-off future. Looking back into the great uncertain ranges of past time, he saw "no sign of a start, no sign of an end."
The Vulcanists as an attack on religion
These very Pythagorean views of the Vulcanists (as they were named, possibly not without humor, after Vulcan, the Roman fire-god) were taken as an attack on religion; and this put expert opinion completely against them. Here the outlook of society had an important effect.
The French 'Revolution'5 of 1789 was full of political danger to the other governments of Europe. Somewhere at the back of the Revolution were the ideas of Voltaire and the Encyclopaedists, who had made frequent attacks on the Church and the Bible; so that there was a natural chain of half-unconscious suggestion joining thoughts about 'Jacobinism' (being a supporter of the Revolution), about questioning the Bible, and about having no belief in God. Against this general feeling all Playfair's attempts to make it clear that Hutton had never said there was no God had not the smallest effect. Though Sir James Hall, using a development of De Saussure's tests on minerals, made it certain that rock heated till liquid gave something with a structure very like basalt, this did not have any weight with those who saw that the Wernerian theory gave room for a Creation and a Flood, the Huttonian did not.
This was the position till 1830-1833, when the Principles of Geology of Charles Lyell (1797-1875) was first put before the public. What Werner might have done for Geology, Lyell did: putting together a beautifully ordered structure from the great and ever-increasing mass of observations, in a clear and balanced prose which of itself gave weight to his views. The great number of experts in geology before and after Lyell make hard reading: as if they did their work hammer in hand. Not so, Lyell, whose knowledge of Gibbon had given him more, possibly, than he got from Hutton and Playfair. The art of writing a prose at once strong and delicate, balanced and natural, with all the force of a great mind, is not common enough among men of science for this side of Lyell's work to be overlooked. His theory went farther than Hutton, his facts came from a wider field; and the full force of his argument was on the side of an evolutionary view of the Earth's history. What was named the "Uniformitarian theory" gave an account of the evolution of the rocks by slow and regular ('uniform') changes, of the sort still seen acting, working unendingly through a time so long that in its great stretch the buildings of old Egypt were no older and for no longer than last night's snow-fall.
Against this view there was not only the school of Freiburg, but that of the 'Catastrophists,' who had a belief in a past of sudden and violent changes ('catastrophes'), among which the Flood might be put. Here there was a connection with the sciences of living things: in France, De Lamarck (1744-1829) and Cuvier (1769-1882) took opposite views of the past history of the animals, the first having a belief in change by a sort of self-adjustment to natural conditions, while the second was a supporter of the old belief in the sudden general destruction of living forms, after which there came a new stage of development. There was no doubt by this time that a number of species', or sorts, of animals had come completely to an end; while others seen at the present day seemed not to have been in existence in the past (though this was naturally less certain, the chances of getting the fossils being small). Lamarck's theory was that animals had a power of self-development by something like conscious attempts, the blood and 'living forces' being given a special direction to any parts used in a special way (as, for example, the cow-family makes use of its head in fighting, or the horse-family of its legs in running); and that these developments were given by the animal to its young. (It is this last idea, that changes in the living animal may have an effect on its offspring, which is now commonly named Lamarckism.)
In this there was an idea of Evolution, as opposite to the belief that God made the animals at the Creation, one and all in their present forms. A number of arguments for change in species had been put forward by Erasmus Darwin in his Zobnomia (1796) and in notes to his works in verse; but (then as now) the writer of The Loves of the Plants was not taken very seriously. Earlier again, Robert Hoake had had an idea of the possible effects of living-conditions, seen the different forms of the same species in the animals kept by man (dogs, sheep, etc.), and made the suggestion that small regular changes in what were at first only different examples of the same species might, in time, give lines of offspring so different that they would not be judged to be of the same species.6 A strong argument, first put forward by Erasmus Darwin and used later by Charles, came from Cuvier's work on Anatomy, in which it was seen that the species grouped together commonly had structures with a general design, as if there were only a certain number of forms, which had undergone special adjustments for their special conditions and behaviors. This seemed to make it necessary to say that God's powers of invention were somewhat limited: an improbable way out of a hard question.
Zoology and Botany
Here a short note may be given on the past history of Zoology and Botany, and specially on this question of grouping, or classification*. In 1660 John Ray had made his system of plants, in which those with one seedleaf (Monocotyledons) were first grouped separately from those with two (Dicotyledons); and in 1676 Nehemiah Grew, another Fellow of the Royal Society, had taken the first steps in the discovery of the sex-organs* in plants. This work was taken farther by Rudolf Camerarius (1665-1721) and Geoffroy, till Carl von Linné, or Linnaeus (1707-1778) put forward his complete system of groupings. Like Ray, Linnaeus went on from plants to animals, and it is from his work that we get our system of international names in the Latin form. His observations made it clear that the place of Man in the system was with the Apes, or higher monkeys; and from about 1770 playing with the idea that the two were relations was one of the amusements of men of learning with a taste for something out of the common. Discoveries of fossil Man , however, are not very frequent; so that even in Lyell's time it was possible to say that no signs of his existence had been seen in any but the newest orders of rocks...
In England, William Smith (1769-1839) had put into effect Hooke's uncertain idea of a time-scale of the rocks, using the fossil groups as guides. The wide observation and detailed geological maps produced by this great worker had been the mark of a new stage in the science.
In 1808 Cuvier and Brogniart had done the same work with the rocks of the Paris Basin, when the first had put together the fossil bones of a number of animals no longer seen anywhere on earth, some of them of a quite shockingly improbable size. Work of the same sort was done later by Saint-Hilaire (1772-1844), who was a strong supporter of the theories of Lamarck. In 1844 there was printed a book named Vestiges of Creation, by Robert Chambers (1802-1871), though he did not put his name to it. This, like the writings of Herbert Spencer (1820-1903), had in it a general idea of evolution, though there was still no ordered basework of detailed facts, and no suggestion of a process less uncertain and generally improbable than Lamarck's.
These were the conditions under which Darwin's theory was put forward; and strong as was the position of the Bible in England, great though the dangers were of openly making a suggestion that its account was false, the very fact that belief was so important made this the most probable country to be the heart of the latest great war between Science and 'Religion,' that is to say, the Churches.
Like most of the great theories, Darwin's is simple. His special quality was that of being able to take a far-ranging and detailed mass of facts and give it an order and design, much as Newton had done with the facts of motion. Only -- and it is an important point -- there was here no question of using the clear and certain authority of numbers. Like Geology, the sciences of living things are necessarily based on reasoned argument about what seems probable. Where time is all-important, the only possible base for theory is argument from the little which may be seen to the much which might be.
The uniting idea of the theory seems to have taken form at different times in the minds of Darwin and A. R. Wallace as the effect of reading the same book: Malthus's Essay of Population (1798), which Darwin had seen in 1838, and Wallace 20 years later, though before Darwin had made his theory public. Malthus's theory was that there was a natural tendency for the number of living persons (the 'population') to go on increasing till there was not enough food; when the condition was only balanced again by war, disease, or some other cause of a high death-rate (such as need of food). Darwin and Wallace saw 430 that under these conditions there was a tendency for those who were 'better' in some way to keep themselves from death; if not as far as the natural limit, at least long enough for them to have more offspring than those who were 'worse.'
This is "the survival of the fittest": a formula* of words which has from the first been a general cause of error.7 The sense of 'survival' is simply the one we have given ('going on living long enough to have offspring'); but that of 'fittest' ('best able to go on living in the conditions') was taken to have a suggestion of 'necessarily better' about it (the 'better' being measured in some less simple scale of values) which is unsupported by Darwin's use and by the facts. The Thread-worm is not 'better' than the Mammoth (Elephas primigenius) in any but the sense that thread-worms are still among us, while mammoths are not.
Darwin's theory of "natural selection" said that in any group of offspring no two would be quite the same in every smallest detail. Under changing conditions (of weather, food, the attacks of other animals) some of these small details might be a great help in the general competition for the needs of existence which had been named "the struggle for existence."8 If conditions were hard enough, this small detail might have 'survival-value'; so that this one animal had offspring, while his brothers and sisters did not, or had less. In the family produced by this animal (in the second 'generation,' that is) there might again be two or more with the special qualities which had given their father a better chance of 'survival'; so that in time the number of that species with what had at first been an uncommon quality would be increased till what had been 'uncommon' was now 'normal' among that group. This process of automatic adjustment to living-conditions was "natural selection.'
Competition between animals of the same sort, taken as sex-groups, is part of the 'conditions.' In general, the males will be in competition for the females: so that being able to keep up the fight against weather, need of food, etc., is only part of the war. 'Environment,' or the living-conditions, then, is not a simple thing: it takes in everything which may have an effect on offspring-producing in numbers greater than the 'mean.'
Taking the argument the other way, into the past, it becomes clear that this process of adjustment gives a reason for the general design to be seen in animals of the same great groups (Mammals,9 Fish, Birds, Insects, and so on) and for the special qualities seen in the species. A species is a development of one general design which has gone through a long process of adjustment to special environments. Whales,10 for example, are mammals which have gone through a process of adjustment to fish-like conditions: the ostrich,11 emu,'12 and cassowary' 13 are birds which have gone through a process of increase of weight and power of running, and loss of the power of flight; and so on. But all these special forms seem to be developments of a small number of simpler designs; so that there has been a process of development in time from simple to complex, as an effect of natural selection, which is the 'cause' of the different species. Going back farther, there was at some time deep in the past some one First Living Thing, the Adam of the plants and animals; and from it all things have been produced by this process of evolution of complex from simple, under the ever-present forces of change and destruction.
Darwin's theory was supported by facts from all fields of observation; and it gave ideas as widely as it took. In Geology it gave a most clear and certain reason for the distribution of the fossils in the different beds, and made it clear why the higher forms of living things were never seen in any but the newest beds, while in the older and deeper rocks only the simplest forms were seen. It gave a new authority to Smith's time-scale, and made Palaeontology 14 less the natural history of the past than a science of the causes of the present. To all questions about the order of fossils, there was no answer but Darwin's.
15 Evolution put together the facts from Geology and Palaeontology, those from Comparative Anatomy and Morphology (the structure of animal forms), the observations used in grouping, the special knowledge got from producing the animals in common use among men, and made it clear that through this theory these were all in agreement with one another, and with what might be seen to take place among animals or plants under natural conditions, and with the facts of their distribution in different parts of the earth. In addition to all this, it gave a reason for the existence of signs of parts which seemed to be of no use (those of leg-bones in one form of snake, the tail-structures in the Apes and in Man, and the wings of running-birds, never used in flight): feeble, unused, and incomplete structures for which the theory of Special Creation (as in the Bible story) was able to give no reason at all. Again, the theory had the support of Embryology, in which a sort of fossil behavior had been seen in the development of the embryo16 of the higher animals, a tendency for certain parts to go through stages in which they were like those of simpler animals. (In fishes, for example, there is a worm-stage; in mammals, a fish-stage.) This had been noted in the brain by Tiedemann, and made the base of a theory of Embryology by Meckel (1781-1833).
It gave Darwin an important parallel to the fossil-record, in which there was the same order of simple-to-complex; and, again, it was not very clear why there was any need for animals made by Special Creation to go through these roundabout stages.
The effect of the Origin of Species on the general current of thought was greater than that of any theory from the time of Copernicus. It was, it might be said, an effect of the same sort. Copernicus had taken away the Earth from the middle of the Universe,17 and put it among the other stars: Darwin had put Man among the animals, and made living things the outcome of their physical conditions. But where Newton's system had given comforting suggestions of an unlimited care in the adjustment of parts to purpose, Evolution seemed at first to take all sense and value from the idea of purpose: to make Man no more than a chance-formed Higher Ape, looking on for a time at the unresting currents of change by which he had been forced into being, and by which he would, in time, be sent the way of the Pterodactyl, the Ichthyosaurus, and the Mammoth, a man of stone among the fossils of the ice-cold rocks.18
The reaction was quick and violent. Society was ready to have a belief in the effects of environment: the desire for wider education is a sign of it, and this was common talk long before Darwin's time. It was ready to see that 'everything had a use,' and that competition was a 'law of existence'; but it was less ready to see that men might not be completely responsible for their qualities, and not ready at all to have anything to do with a theory which said that the story of Creation was untrue, that Man was a somewhat less indelicate form of Monkey, and that he was not under the guiding hand of God, but part of an unending round of changes and destructions without purpose or design, with no reason for his existence, and no reward at the end of it. About a great number of these things Darwin had said nothing; but it was in this form that the theory came before the minds of the public, and was attacked by the newspapers, by the churches, by political authorities, by private letters; by almost every sort of man with a low opinion of the monkey and a high one of himself. Unlike the wave-theory of light or the laws of Thermodynamics, this was a question in which everyone seemed (to himself) to be a good judge.
For a number of years Darwin and T. H. Huxley and their supporters were kept fighting for the theory, till the churchmen had taken to reading science, and had made the surprising discovery that the hand of God might be as clearly seen in the long and complex process of evolution as in the unnatural industry of the Third, Fifth, and Sixth Days. On science the effect was like that of a fixed bright light; but while some branches underwent a new stage of growth, Biology went almost to sleep for forty years, in which Natural Selection seemed to have given the first, last, and only formula.
In Geology, the great work of Lyell had given so much order that the Uniformitarian theory was the baseline from which almost all future developments were made. The systems of beds under (and older than) the Old Red Sandstone had been slowly worked out by the discoveries of Adam Sedgwick (1785-1873) and Sir Roderick Murchison (1792-1871); American geology, started by William Maclure in 1807, became important with the work of J. D. Dana (1813-1895); and by 1900 the formations* in almost all countries had been worked out by the discoveries of an army of experts using the fossils in what was, at root, Smith's way, and working by a general theory which was Lyell's in design. Knowledge of the conditions and effects of 'ice-ages' had been started by Agassiz in 1840; and though not given full attention till the work of Sir Archibald Geikie (1863) and his son James (1874), was then seen to be an important addition to theory.
The details of the discovery of the different systems and their working-out have no place in a general history; but in all this work, the evolution theories of the building of the Earth and the development of the animals and plants took on an authority like that of the Newtonian system in physics. Observations which seemed to give results not in agreement with the theory were not taken as a sign that it might be false, but as making it certain that if the order of guide-fossils was not regular, then the strata had been violently overturned or twisted in some way, after the fossils were bedded in them. Here Darwin's work is a first step in the direction of later discoveries about the age of the Earth.
It is not hard to see that there is a method in common between the work of Hutton and Lyell, Wallace and Darwin: one in which Past and Present are seen as united parts of an unbroken and regular process.
To put it simply, the method is that of History: only History on a greater scale, and with Man at a different level. When Darwin's later books and Huxley's Man's Place in Nature (1863) had taken their place among valued works of science, this method had taken discovery into some completely new fields. Science took a new and important line when Man was seen as the outcome of his natural conditions.