The Foundations of the Origin of Species Two Essays written in 1842 and 1844 · Charles Darwin
PART II{104}.
With equal probability did old cosmogonists say fossils were created, as we now see them, with a false resemblance to living beings{105}; what would the Astronomer say to the doctrine that the planets moved <not> according to the law of gravitation, but from the Creator having willed each separate planet to move in its particular orbit? I believe such a proposition (if we remove all prejudices) would be as legitimate as to admit that certain groups of living and extinct organisms, in their distribution, in their structure and in their relations one to another and to external conditions, agreed with the theory and showed signs of common descent, and yet were created distinct. As long as it was thought impossible that organisms should vary, or should anyhow become adapted to other organisms in a complicated manner, and yet be separated from them by an impassable barrier of sterility{106}, it was justifiable, even with some appearance in favour of a common descent, to admit distinct creation according to the will of an Omniscient Creator; or, for it is the same thing, to say with Whewell that the beginnings of all things surpass the comprehension of man. In the former sections I have endeavoured to show that such variation or specification is not impossible, nay, in many points of view is absolutely probable. What then is the evidence in favour of it and what the evidence against it. With our imperfect knowledge of past ages [surely there will be some] it would be strange if the imperfection did not create some unfavourable evidence.
I conceive there is no probability whatever of this; nevertheless it is certain all the numerous fossil forms fall in<to>, as Buckland remarks, _not_ present classes, families and genera, they fall between them: so is it with new discoveries of existing forms. Most ancient fossils, that is most separated <by> space of time, are most apt to fall between the classes--(but organisms from those countries most separated by space also fall between the classes <_e.g._> Ornithorhyncus?). As far as geological discoveries <go> they tend towards such gradation{110}. Illustrate it with net. Toxodon,--tibia and fibula,--dog and otter,--but so utterly improbable is <it>, in _ex. gr._ Pachydermata, to compose series as perfect as cattle, that if, as many geologists seem to infer, each separate formation presents even an approach to a consecutive history, my theory must be given up. Even if it were consecutive, it would only collect series of one district in our present state of knowledge; but what probability is there that any one formation during the _immense_ period which has elapsed during each period will _generally_ present a consecutive history. [Compare number living at one period to fossils preserved--look at enormous periods of time.] {107} See _Origin_, Ed. i. p. 312, vi. p. 453. {108} See _Origin_, Ed. i. pp. 280, 281, vi. p. 414. The author uses his experience of pigeons for examples for what he means by _intermediate_; the instance of the horse and tapir also occurs.
Our theory requires that the first form which existed of each of the great divisions would present points intermediate between existing ones, but immensely different. Most geologists believe Silurian{117} fossils are those which first existed in the whole world, not those which have chanced to be the oldest not destroyed,--or the first which existed in profoundly deep seas in progress of conversion from sea to land: if they are first they <? we> give up. Not so Hutton or Lyell: if first reptile{118} of Red Sandstone <?> really was first which existed: if Pachyderm{119} of Paris was first which existed: fish of Devonian: dragon fly of Lias: for we cannot suppose them the progenitors: they agree too closely with existing divisions. But geologists consider Europe as <?> a passage from sea to island <?> to continent (except Wealden, see Lyell). These animals therefore, I consider then mere introduction <?> from continents long since submerged. {117} Compare _Origin_, Ed. i. p. 307, vi. p. 448. {118} I have interpreted as _Sandstone_ a scrawl which I first read as _Sea_; I have done so at the suggestion of Professor Judd, who points out that "footprints in the red sandstone were known at that time, and geologists were not then particular to distinguish between Amphibians and Reptiles." {119} This refers to Cuvier's discovery of _Palaeotherium_ &c. at Montmartre.
Finally, if views of some geologists be correct, my theory must be given up. [Lyell's views, as far as they go, are in _favour_, but they go so little in favour, and so much more is required, that it may <be> viewed as objection.] If geology present us with mere pages in chapters, towards end of <a> history, formed by tearing out bundles of leaves, and each page illustrating merely a small portion of the organisms of that time, the facts accord perfectly with my theory{120}. {120} This simile is more fully given in the _Origin_, Ed. i. p. 310, vi. p. 452. "For my part, following out Lyell's metaphor, I look at the natural geological record, as a history of the world imperfectly kept, and written in a changing dialect; of this history we possess the last volume alone, relating only to two or three countries. Of this volume, only here and there a short chapter has been preserved; and of each page, only here and there a few lines. Each word of the slowly-changing language, in which the history is supposed to be written, being more or less different in the interrupted succession of chapters, may represent the apparently abruptly changed forms of life, entombed in our consecutive, but widely separated formations." Professor Judd has been good enough to point out to me, that Darwin's metaphor is founded on the comparison of geology to history in Ch. i. of the _Principles of Geology_, Ed. i. 1830, vol. i. pp. 1-4. Professor Judd has also called my attention to another passage,--_Principles_, Ed. i. 1833, vol. iii. p. 33, when Lyell imagines an historian examining "two buried cities at the foot of Vesuvius, immediately superimposed upon each other." The historian would discover that the inhabitants of the lower town were Greeks while those of the upper one were Italians. But he would be wrong in supposing that there had been a sudden change from the Greek to the Italian language in Campania. I think it is clear that Darwin's metaphor is partly taken from this passage. See for instance (in the above passage from the _Origin_) such phrases as "history ... written in a changing dialect"--"apparently abruptly changed forms of life." The passage within [] in the above paragraph:--"Lyell's views as far as they go &c.," no doubt refers, as Professor Judd points out, to Lyell not going so far as Darwin on the question of the imperfection of the geological record.
_Extermination._ We have seen that in later periods the organisms have disappeared by degrees and [perhaps] probably by degrees in earlier, and I have said our theory requires it. As many naturalists seem to think extermination a most mysterious circumstance{121} and call in astonishing agencies, it is well to recall what we have shown concerning the struggle of nature. An exterminating agency is at work with every organism: we scarcely see it: if robins would increase to thousands in ten years how severe must the process be. How imperceptible a small increase: fossils become rare: possibly sudden extermination as Australia, but as present means very slow and many means of escape, I shall doubt very sudden exterminations. Who can explain why some species abound more,--why does marsh titmouse, or ring-ouzel, now little change,--why is one sea-slug rare and another common on our coasts,--why one species of Rhinoceros more than another,--why is <illegible> tiger of India so rare? Curious and general sources of error, the place of an organism is instantly filled up. {121} On rarity and extinction see _Origin_, Ed. i. pp. 109, 319, vi. pp. 133, 461. We know state of earth has changed, and as earthquakes and tides go on, the state must change,--many geologists believe a slow gradual cooling. Now let us see in accordance with principles of [variation] specification explained in Sect. II. how species would probably be introduced and how such results accord with what is known.
The first fact geology proclaims is immense number of extinct forms, and new appearances. Tertiary strata leads to belief, that forms gradually become rare and disappear and are gradually supplied by others. We see some forms now becoming rare and disappearing, we know of no sudden creation: in older periods the forms _appear_ to come in suddenly, scene shifts: but even here Devonian, Permian &c. [keep on supplying new links in chain]--Genera and higher forms come on and disappear, in same way leaving a species on one or more stages below that in which the form abounded.
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