lamarck

Lamarck on Species, Environment, and Habit

I'd often heard the name of Jean Baptist Lamarck used, in biology courses, etc., but always in vain: he was a guy to ridicule because he believed in "the inheritance of acquired characteristics", which is to say that he believed the acquired habits and characteristics of parents were passed on to offspring. This was supposed to be dumb of him, since we know that the genetic constitution of parents is what they pass on to their offspring, and that genes are not changed by the behaviour of organisms which carry them. Genetics, of course, dates from after 1900, whereas Lamarck's Zoological Philosophy: An Exposition with Regard to the Natural History of Animals was published in 1809. And there's the sticky fact that Darwin, in 1859, used the same theory to explain the origin of differences within a species (he didn't like it, but it was the best he had). Gregory Bateson, in his remarkable 1970 article "Form, Substance and Difference" (reprinted in his Steps to an Ecology of Mind) said on the contrary that Lamarck thought evolution was obvious, though his interest was really in "comparative psychology, a science which he founded". Bateson says: "Before Lamarck, the organic world, the living world, was believed to be hierarchic in structure, with Mind [God] at the top. The chain, or ladder, went down through the angels, through men, through the apes, down to the infusoria or protozoa, and below that to the plants and stones. What Lamarck did was to turn that chain upside down. He observed that animals changed under environmental pressure.... When he turned the ladder upside down, what had been the explanation, namely, the Mind at the top, now became that which had to be explained. His problem was to explain Mind. He was convinced about evolution, and there his interest in it stopped." In the passages I've selected below, my interest is in Lamarck's environmental/evolutionary argument, mostly. His comparative psychology of the animals is pretty much predictable from the sensationalism of the Enlightenment, even though it's phrased in terms of the nervous system and other physiological evidence.

From Part I, Chapter 3: Of Species among Living Bodies and the Idea that We should attach to that Word
    IT is not a futile purpose to decide definitely what we mean by the so-called species among living bodies, and to enquire if it is true that species are of absolute constancy, as old as nature, and have all existed from the beginning just as we see them to-day; or if, as a result of changes in their environment, albeit extremely slow, they have not in course of time changed their characters and shape.
    The solution of this question is of importance not only for our knowledge of zoology and botany, but also for the history of the world.
    I shall show... that every species has derived from the action of the environment... the habits which we find in it. These habits have themselves influenced the parts of every individual in the species, to the extent of modifying those parts and bringing them into relation with the acquired habits. Let us first see what is meant by the name of species.
    Any collection of like individuals which were produced by others similar to themselves is called a species.
    This definition is exact; for every individual possessing life always resembles very closely those from which it sprang; but to this definition is added the allegation that the individuals composing a species never vary in their specific characters, and consequently that species have an absolute constancy in nature.
    It is just this allegation that I propose to attack, since clear proofs drawn from observation show that it is ill-founded.
    The almost universally received belief is that living bodies constitute species distinguished from one another by unchangeable characteristics, and that the existence of these species is as old as nature herself. This belief became established at a time when no sufficient observations had been taken. and when natural science was still almost negligible. It is continually being discredited.... ...[A]ll those who are much occupied with the study of natural history, know that naturalists now find it extremely difficult to decide what objects should be regarded as species.... ...Hence, naturalists come to arbitrary decisions about individuals observed in various countries and diverse conditions, sometimes calling them varieties and sometimes species. The work connected with the determination of species therefore becomes daily more defective, that is to say, more complicated and confused....
    Doubtless, nothing exists but by the will of the Sublime Author of all things, but can we set rules for him in the execution of his will, or fix the routine for him to observe? Could not his infinite power create an order of things which gave existence successively to all that we see as well as to all that exists but that we do not see?
    Assuredly, whatever his will may have been, the immensity of his power is always the same, and in whatever manner that supreme will may have asserted itself, nothing can diminish its grandeur.
    I shall then respect the decrees of that infinite wisdom and confine myself to the sphere of a pure observer of nature. If I succeed in unravelling anything in her methods, I shall say without fear of error that it has pleased the Author of nature to endow her with that faculty and power....

From: Chapter 7: Of the Influence of the Environment on the Activities and Habits of Animals, and the Influence of the Activities and Habits of these Living Bodies in Modifying their Organization and Structure
...the infinitely diversified but slowly changing environment in which the animals of each race have successively been placed, has involved each of them in new needs and corresponding alterations in their habits. This is a truth which, once recognised, cannot be disputed. Now we shall easily discern how the new needs may have been satisfied, and the new habits acquired, if we pay attention to the two following laws of nature, which are always verified by observation.

FIRST LAW.
In every animal which has not passed the limit of its development, a more frequent and continuous use of any organ gradually strengthens, develops and enlarges that organ, and gives it a power proportional to the length of time it has been so used; while the permanent disuse of any organ imperceptibly weakens and deteriorates it, and progressively diminishes its functional capacity, until it finally disappears.

SECOND LAW.
All the acquisitions or losses wrought by nature on individuals, through the influence of the environment in which their race has long been placed, and hence through the influence of the predominant use or permanent disuse of any organ; all these are preserved by reproduction to the new individuals which arise, provided that the acquired modifications are common to both sexes, or at least to the individuals which produce the young.

    Here we have two permanent truths, which can only be doubted by those who have never observed or followed the operations of nature, or by those who have allowed themselves to be drawn into the error which I shall now proceed to combat.
    Naturalists have remarked that the structure of animals is always in perfect adaptation to their functions, and have inferred that the shape and condition of their parts have determined the use of them. Now this is a mistake: for it may be easily proved by observation that it is on the contrary the needs and uses of the parts which have caused the development of these same parts, which have even given birth to them when they did not exist, and which consequently have given rise to the condition that we find in each animal.
    If this were not so, nature would have had to create as many different kinds of structure in animals, as there are different kinds of environment in which they have to live; and neither structure nor environment would ever have varied.
    This is indeed far from the true order of things. If things were really so, we should not have race-horses shaped like those in England; we should not have big draught-horses so heavy and so different from the former, for none such are produced in nature; in the same way we should not have basset-hounds with crooked legs, nor grey-hounds so fleet of foot, nor water-spaniels, etc.; we should not have fowls without tails, fantail pigeons, etc. ; finally, we should be able to cultivate wild plants as long as we liked in the rich and fertile soil of our gardens, without the fear of seeing them change under long cultivation.
    A feeling of the truth in this respect has long existed ; since the following maxim has passed into a proverb and is known by all, Habits form a second nature.
    Assuredly if the habits and nature of each animal could never vary, the proverb would have been false and would not have come into existence, nor been preserved in the event of any one suggesting it.
    If we seriously reflect upon all that I have just set forth, it will be seen that I was entirely justified when in my work entitled Recherches sur les corps vivants (p.50), I established the following proposition
    "It is not the organs, that is to say, the nature and shape of the parts of an animal's body, that have given rise to its special habits and faculties ; but it is, on the contrary, its habits, mode of life and environment that have in course of time controlled the shape of its body, the number and state of its organs and, lastly, the faculties which it possesses."...
    Time and a favourable environment are... nature's two chief methods of bringing all her productions into existence: for her, time has no limits and can be drawn upon to any extent.
    As to the various factors which she has required and still constantly uses for introducing variations in everything that she produces, they may be described as practically inexhaustible.
    The principal factors consist in the influence of climate, of the varying temperatures of the atmosphere and the whole environment, of the variety of localities and their situation, of habits, the commonest movements, the most frequent activities, and, lastly, of the means of self-preservation, the mode of life and the methods of defence and multiplication.
    Now as a result of these various influences, the faculties become extended and strengthened by use, and diversified by new habits that are long kept up. The conformation. consistency and, in short, the character and state of the parts, as well as of the organs, are imperceptibly affected by these influences and are preserved and propagated by reproduction....
    Now I am going to prove that the permanent disuse of any organ first decreases its functional capacity, and then gradually reduces the organ and causes it to disappear or even become extinct, if this disuse lasts for a very long period throughout successive generations of animals of the same race.
    I shall then show that the habit of using any organ, on the contrary, in any animal which has not reached the limit of the decline of its functions, not only perfects and increases the functions of that organ, but causes it in addition to take on a size and development which imperceptibly alter it ; so that in course of time it becomes very different from the same organ in some other animal which uses it far less...
    ...nature shows us in innumerable other instances the power of environment over habit and that of habit over the shape, arrangement and proportions of the parts of animals.
    Since there is no necessity to cite any further examples, we may now turn to the main point elaborated in this discussion.
    It is a fact that all animals have special habits corresponding to their genus and species, and always possess an organisation that is completely in harmony with those habits. It seems from the study of this fact that we may adopt one or other of the two following conclusions, and that neither of them can be verified.
    Conclusion adopted hitherto: Nature (or her Author) in creating animals, foresaw all the possible kinds of environment in which they would have to live, and endowed each species with a fixed organisation and with a definite and invariable shape, which compel each species to live in the places and climates where we actually find them, and there to maintain the habits which we know in them.
    My individual conclusion: Nature has produced all the species of animals in succession, beginning with the most imperfect or simplest, and ending her work with the most perfect, so as to create a gradually increasing complexity in their organisation; these animals have spread at large throughout all the habitable regions of the globe, and every species has derived from its environment the habits that we find in it and the structural modifications which observation shows us.
    The former of these two conclusions is that which has been drawn hitherto, at least by nearly everyone: it attributes to every animal a fixed organisation and structure which never have varied and never do vary; it assumes, moreover, that none of the localities inhabited by animals ever vary ; for if they were to vary, the same animals could no longer survive, and the possibility of finding other localities and transporting themselves thither would not be open to them.
    The second conclusion is my own: it assumes that by the influence of environment on habit, and thereafter by that of habit on the state of the parts and even on organisation, the structure and organisation of any animal may undergo modifications, possibly very great, and capable of accounting for the actual condition in which all animals are found.
    In order to show that this second conclusion is baseless, it must first be proved that no point on the surface of the earth ever undergoes variation as to its nature, exposure, high or low situation, climate, etc., etc.; it must then be proved that no part of animals undergoes even after long periods of time any modification due to a change of environment or to the necessity which forces them into a different kind of life and activity from what has been customary to them.
    Now if a single case is sufficient to prove that an animal which has long been in domestication differs from the wild species whence it sprang, and if in any such domesticated species, great differences of conformation are found between the individuals exposed to such a habit and those which are forced into different habits, it will then be certain that the first conclusion is not consistent with the laws of nature, while the second, on the contrary, is entirely in accordance with them.
    Everything then combines to prove my statement, namely: that it is not the shape either of the body or its parts which gives rise to the habits of animals and their mode of life; but that it is, on the contrary, the habits, mode of life and all the other influences of the environment which have in course of time built up the shape of the body and of the parts of animals. With new shapes, new faculties have been acquired, and little by little nature has succeeded in fashioning animals such as we actually see them.
    Can there be any more important conclusion in the range of natural history, or any to which more attention should be paid than that which I have just set forth?

From Part III, Chapter 8: Of the Principle Acts of the Understanding, or those of the First Order from which All the Rest are Derived. This section of the chapter is called: Of Reason, and its Comparison with Instinct.
{He divides "the principle functions" of the "organ of intelligence" into four: the acts of attention, thought, memory, and judgement.}
    Reason is not a faculty; still less is it a torch or entity of any kind; but it is a special condition of the individual's intellectual faculties; a condition that is altered by experience, gradually improves and controls the judgments, according as the individual exercises his intellect.
    Reason therefore is a quality that may be possessed in different degrees, and this quality can only be recognised in a being that possesses certain intellectual faculties.
    In the last analysis, it may be said that for all individuals endowed with intelligence, reason is nothing more than a stage acquired in the rectitude of judgments.
    No sooner are we born than we experience sensations, mainly from external objects affecting our senses; we quickly acquire ideas, which are formed in us as a result of noticed sensations; and we soon compare almost mechanically the objects we have noticed and thus form judgments.
    But we are then new to the whole of our environment, destitute of experience, and deceived by some of our senses, so that we judge badly; we are mistaken as to the distances, shapes, colours, and consistency of the objects that we notice, and we do not grasp the relations existing between them. It is necessary that several of our senses should combine gradually to destroy our errors and rectify our judgments; lastly, it is only with the help of time, experience, and attention paid to the objects which affect us, that rectitude is slowly attained in our judgments.
    The same thing is true with regard to our complex ideas, and the useful truths, rules, or precepts communicated to us. It is only by means of much experience, and memory in collecting all the elements for an inference; only by means of the greatest use of our understanding that our judgment on these matters is gradually improved.
    Hence the wide difference existing between the judgments of childhood and those of youth; hence again the difference found between the judgments of a young man of twenty and those of a man of forty or more, when the intellect in both cases has always been regularly exercised.

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