Chapter 15

WHEN DID LAMARCK CHANGE HIS VIEWS REGARDING THE MUTABILITY OF SPECIES?

Lamarck's mind was essentially philosophical. He was given to inquiring into the causes and origin of things. When thirty-two years old he wrote his "Researches on the Causes of the Principal Physical Facts," though this work did not appear from the press until 1794, when he was fifty years of age. In this treatise he inquires into the origin of compounds and of minerals; also he conceived that all the rocks as well as all chemical compounds and minerals originated from organic life. These inquiries were reiterated in his "Memoirs on Physics and Natural History," which appeared in 1797, when he was fifty-three years old.

The atmosphere of philosophic France, as well as of England and Germany in the eighteenth century, was charged with inquiries into the origin of things material, though more especially of things immaterial. It was a period of energetic thinking. Whether Lamarck had read the works of these philosophers or not we have no means of knowing. Buffon, we know, was influenced by Leibnitz.

Did Buffon's guarded suggestions have no influence on the young Lamarck? He enjoyed his friendship and patronage in early life, frequenting his house, and was for a time the travelling companion of Buffon's son. It should seem most natural that he would have been personally influenced by his great predecessor, but we see no indubitable trace of such influence in his writings. Lamarckism is not Buffonism. It comprises in the main quite a different, more varied and comprehensive set of factors.[158]

Was Lamarck influenced by the biological writings of Haller, Bonnet, or by the philosophic views of Condillac, whose _Essai sur l'Origine des Connaissances humaines_ appeared in 1786; or of Condorcet, whom he must personally have known, and whose _Esquisse d'un Tableau historique des Progrès de l'Esprit humain_ was published in 1794?[159] In one case only in Lamarck's works do we find reference to these thinkers.

Was Lamarck, as the result of his botanical studies from 1768 to 1793, and being puzzled, as systematic botanists are, by the variations of the more plastic species of plants, led to deny the fixity of species?

We have been unable to find any indications of a change of views in his botanical writings, though his papers are prefaced by philosophical reflections.

It would indeed be interesting to know what led Lamarck to change his views. Without any explanation as to the reason from his own pen, we are led to suppose that his studies on the invertebrates, his perception of the gradations in the animal scale from monad to man, together with his inherent propensity to inquire into the origin of things, also his studies on fossils, as well as the broadening nature of his zoölogical investigations and his meditations during the closing years of the eighteenth century, must gradually have led to a change of views.

It was said by Isidore Geoffroy St. Hilaire that Lamarck was "long a partisan of the immutability of species,"[160] but the use of the word "partisan" appears to be quite incorrect, as he only in one instance expresses such views.

The only place where we have seen any statement of Lamarck's earlier opinions is in his _Recherches sur les Causes des principaux Faits physiques_, which was written, as the "advertisement" states, "about eighteen years" before its publication in 1794. The treatise was actually presented April 22, 1780, to the Académie des Sciences.[161] It will be seen by the following passages, which we translate, that, as Huxley states, this view presents a striking contrast to those to be found in the _Philosophie zoologique_:

"685. Although my sole object in this article [article premier, p. 188] has only been to treat of the physical cause of the maintenance of life of organic beings, still I have ventured to urge at the outset that the existence of these astonishing beings by no means depends on nature; that all which is meant by the word nature cannot give life--namely, that all the faculties of matter, added to all possible circumstances, and even to the activity pervading the universe, cannot produce a being endowed with the power of organic movement, capable of reproducing its like, and subject to death.

"686. All the individuals of this nature which exist are derived from similar individuals, which, all taken together, constitute the entire species. However, I believe that it is as impossible for man to know the physical origin of the first individual of each species as to assign also physically the cause of the existence of matter or of the whole universe. This is at least what the result of my knowledge and reflection leads me to think. If there exist any varieties produced by the action of circumstances, these varieties do not change the nature of the species (_ces variétés ne dénaturent point les espèces_); but doubtless we are often deceived in indicating as a species what is only a variety; and I perceive that this error may be of consequence in reasoning on this subject" (tome ii., pp. 213-214).

It must apparently remain a matter of uncertainty whether this opinion, so decisively stated, was that of Lamarck at thirty-two years of age, and which he allowed to remain, as then stated, for eighteen years, or whether he inserted it when reading the proofs in 1794. It would seem as if it were the expression of his views when a botanist and a young man.

In his _Mémoires de Physique et d'Histoire naturelle_, which was published in 1797, there is nothing said bearing on the stability of species, and though his work is largely a repetition of the _Recherches_, the author omits the passages quoted above. Was this period of six years, between 1794 and 1800, given to a reconsideration of the subject resulting in favor of the doctrine of descent?

Huxley quotes these passages, and then in a footnote (p. 211), after stating that Lamarck's _Recherches_ was not published before 1794, and stating that at that time it presumably expressed Lamarck's mature views, adds: "It would be interesting to know what brought about the change of opinion manifested in the _Recherches sur l'Organisation des Corps vivans_, published only seven years later."

In the appendix to this book (1802) he thus refers to his change of views: "I have for a long time thought that _species_ were constant in nature, and that they were constituted by the individuals which belong to each of them. I am now convinced that I was in error in this respect, and that in reality only individuals exist in nature" (p. 141).

Some clew in answer to the question as to when Lamarck changed his views is afforded by an almost casual statement by Lamarck in the addition entitled _Sur les Fossiles_ to his _Système des Animaux sans Vertèbres_ (1801), where, after speaking of fossils as extremely valuable monuments for the study of the revolutions the earth has passed through at different regions on its surface, and of the changes living beings have there themselves successively undergone, he adds in parenthesis: "_Dans mes leçons j'ai toujours insiste sur ces considérations._" Are we to infer from this that these evolutionary views were expressed in his first course, or in one of the earlier courses of zoölogical lectures--_i.e._, soon after his appointment in 1793--and if not then, at least one or two, or perhaps several, years before the year 1800? For even if the change in his views were comparatively sudden, he must have meditated upon the subject for months and even, perhaps, years, before finally committing himself to these views in print. So strong and bold a thinker as Lamarck had already shown himself in these fields of thought, and one so inflexible and unyielding in holding to an opinion once formed as he, must have arrived at such views only after long reflection. There is also every reason to suppose that Lamarck's theory of descent was conceived by himself alone, from the evidence which lay before him in the plants and animals he had so well studied for the preceding thirty years, and that his inspiration came directly from nature and not from Buffon, and least of all from the writings of Erasmus Darwin.

FOOTNOTES:

[158] See the comparative summary of the views of the founders of evolution at the end of Chapter XVII.

[159] While Rousseau was living at Montmorency "his thought wandered confusedly round the notion of a treatise to be called 'Sensitive Morality or the Materialism of the Age,' the object of which was to examine the influence of external agencies, such as light, darkness, sound, seasons, food, noise, silence, motion, rest, on our corporeal machine, and thus, indirectly, upon the soul also."--_Rousseau_, by John Morley (p. 164).

[160] Butler's _Evolution, Old and New_ (p. 244), and Isidore Geoffroy St. Hilaire's _Histoire naturelle générale_, tome ii., p. 404 (1859).

[161] After looking in vain through both volumes of the _Recherches_ for some expression of Lamarck's earlier views, I found a mention of it in Osborn's _From the Greeks to Darwin_, p. 152, and reference to Huxley's _Evolution in Biology_, 1878 ("Darwiniana," p. 210), where the paragraphs translated above are quoted in the original.