Who can tell what ideas a worm does or does not form? We can watch its actions, and see that they are such as involve what we call design and a perception of its own interest. Under these circumstances it seems better to call the worm a reasonable creature with Dr. Darwin than to say with Lamarck that because worms do not appear to have that organ which he assumes to be the sole means of causing sensation and ideas, therefore they can neither feel nor think. Doubtless they cannot feel and think as many sensations and thoughts as we can, but our ideas of what they can and cannot feel must be formed through consideration of what we see them do, and must be biassed by no theories of what they ought to be able to feel or not feel.
Again Lamarck, shortly after an excellent passage in which he points out that the lower animals gain by experience just as man does (and here probably he had in his mind the passage of Buffon referred to at p. 112 of this work), nevertheless writes:—
"If the facts and considerations put forward in this volume be held worthy of attention, it will follow necessarily that there are some animals which have neither reason nor instinct" (I should be glad to see one of these animals and to watch its movements), "such as those which have no power of feeling; that there are others which have instinct but no degree whatever of reason" (whereas from Dr. Darwin's premises it should follow, and would doubtless be readily admitted by him, that instinct is reason, but reason many times repeated made perfect, and finally repeated by rote; so that far from being prior to reason, as Lamarck here implies, it can only come long afterwards), "such as those which have a system enabling them to feel, but which still lack the organ of intelligence; and finally, that there are those which have not only instinct, but over and above this a certain degree of reasoning power, such as those creatures which have one system for sensations and another for acts involving intelligence. Instinct is with these last animals the motive power of almost all their actions, and they rarely use what little reason they have. Man, who comes next above them, is also possessed of instincts which inspire some of his actions, but he can acquire much reason, and can use it so as to direct the greater part of his actions."[201]
All this will be felt to be less satisfactory than the simple directness of Dr. Darwin. It comes in great measure from following Buffon without being en rapport with him. On the other hand, Lamarck must be admitted to have elaborated the theory of "descent with modification" with no less clearness than Dr. Darwin, and with much greater fulness of detail. There is no substantial difference between the points they wish to establish; Dr. Darwin has the advantage in that not content with maintaining that there will be a power of adaptation to the conditions of an animal's existence which will determine its organism, he goes on to say what the principal conditions are, and shows more lucidly than Lamarck has done (though Lamarck adopts the same three causes in a passage which will follow), that struggle, and consequently modification, will be chiefly conversant about the means of subsistence, of reproduction, and of self-protection. Nevertheless, though Dr. Darwin has said enough to show that he had the whole thing clearly before him, and could have elaborated it as finely as or better than Lamarck himself has done, if he had been so minded, yet the palm must be given to Lamarck on the score of what he actually did, and this I observe to be the verdict of history, for whereas Lamarck's name is still daily quoted, Dr. Darwin's is seldom mentioned, and never with the applause which it deserves.
The resemblance between the two writers—that is to say, the complete coincidence of their views—is so remarkable that the question is forced upon us how far Lamarck knew the substance of Dr. Darwin's theory. Lamarck knew Buffon personally; he had been tutor to Buffon's son, and Buffon had three of Lamarck's volumes on the French Flora printed at the royal printing press;—how can we account for Lamarck's having had Buffon's theory of descent with modification before him for so many years, and yet remaining a partisan of immutability till 1801? Before this year we find no trace of his having accepted evolution; thenceforward he is one of the most ardent and constant exponents which this doctrine has ever had. What was it that repelled him in Buffon's system? How is it that in the 'Philosophie Zoologique' there is not, so far as I can remember, a single reference to Buffon, from whom, however, as we shall see, many paragraphs are taken with but very little alteration?
I am inclined to think that the secret of this sudden conversion must be found in a French translation by M. Deleuze of Dr. Darwin's poem, 'The Loves of the Plants' which appeared in 1800. Lamarck—the most eminent botanist of his time—was sure to have heard of and seen this, and would probably know the translator, who would be able to give him a fair idea of the 'Zoonomia.'
I will give a few of the passages which Lamarck would find in this translation. Speaking of Dr. Darwin, M. Deleuze says:—"Il falloit encore qu'un nouvel observateur, entrant dans la route qui venoit de s'ouvrir, s'y frayât des sentiers ignorés; que liant la physique végétale à la botanique il nous montrât dans les plantes, non seulement des corps organisés soumis à des lois constantes, mais des êtres doués sinon de sensibilité, au moins d'une irritabilité particulière, d'un principe de vie qui leur fait exécuter des mouvements analogues à leurs besoins....[202]
"Il est des animaux et des plantes qui par le laps du tems paroissent avoir éprouvé des changemens dans leur organisation, pour s'accommoder à de nouveaux genres de nourriture et aux moyens de se la procurer. Peut-être les productions de la nature font elles des progrès vers la perfection. Cette idée appuyée par les observations modernes sur l'accroissement progressif des parties solides du globe, s'accorde avec la dignité et la providence du créateur de l'univers."[203]
"La nature semble s'être fait un jeu d'établir entre tous les êtres organisés une sorte de guerre qui entretient leur activité: si elle a donné aux uns des moyens de défense, elle a donné aux autres des moyens d'attaque."[204]
Turning to the 'Botanic Garden' itself, I find that this admirable sentence belongs to M. Deleuze, and not to Dr. Darwin, who, however, has said what comes to much the same thing,[205] as may be seen p. 227 of this volume. But the authorship is immaterial; whether the passage was by Dr. Darwin or M. Deleuze, it was, in all probability, known to Lamarck before his change of front.