Department of History
University of California, Irvine
Instructor:    Dr. Barbara J. Becker


Week 8.  Living Machines

excerpts from
Zoological Philosophy, Vol. 1 (1809)
by Jean-Baptiste Lamarck (1744-1829)
translated by Ian Johnston


My teaching experience has made me sense how much a Philosophical Zoology, that is, a body of precepts relevant to the study of animals and even applicable to other parts of the natural sciences would be useful now, when for the past thirty years our knowledge of the facts of zoology has made considerable progress.

Consequently, I attempted to sketch an outline of this philosophy for use in my classes, to make it easier for my students to understand me.  At that time I had no other purpose.

But to reach a determination of these principles and, by following them, to establish precepts which might guide our study, I had consider the organic structure of the different animals we know about, to think through the particular differences which this organic structure presents in the members of each family, each order, and especially each class, to compare the faculties which these animals have derived from it according to their level of complexity in each race, and finally to recognize the most universal phenomena which this structure presents in the main examples.  I was successively led to include considerations of the most important scientific interest and to examine the most difficult questions in zoology.

In fact, how could I explore the remarkable degradation found in the organic structure of animals, as one goes through the series from the most perfect among them right down to the most imperfect, without looking into what could control such a firm and remarkable fact, something confirmed for me by so many proofs?  Must I not think that nature had produced the different bodies endowed with life in succession, proceeding from the simplest to the most highly organized, since, as we go up the animal scale from the most imperfect right up to the most perfect, the organism's organic structure is developed and gradually becomes more complex in an extremely remarkable way?

This idea, moreover, acquired in my eyes the most conclusive evidence when I recognized that the simplest of all organic structures displays no specialized organs whatever, that the body which possesses such a structure really has no special faculty, but only those appropriate to all living bodies, and that as nature comes to create, one after the other, the different specialized organs and also to increase more and more the complexity of organic structures, the animals acquire different special faculties according to the degree of that complexity, faculties which, in the most perfect among them, are numerous and very strongly marked.

I could not decline to pay attention to these matters.  That soon led me to examine the question about what really constitutes life and what conditions this natural phenomenon requires in order to appear and to be able to remain in a body.  My reluctance to pursue this research was even less because I was then convinced that in the simplest of all structures one could find, in a unique way, the appropriate methods of coming up with the solution to a problem apparently so difficult, because that study alone presented the full array of conditions necessary to the presence of life without anything extra which could mislead.

The complete conditions necessary for the existence of life are found in the least complex organic structure, but also reduced to their simplest terms.  It was a matter of knowing how this structure, whatever the causes of change, was able to lead to other less simple organic structures and to give rise to the gradually more complicated arrangements observed in the range of the scale of animal life.  Using the two following ideas, to which observation led me, I believed I saw the solution to the problem which preoccupied me.

First, there is considerable factual evidence proving that the sustained use of an organ leads to its development, strengthens it, and even makes it grow larger, while a lack of use, once it becomes habitual, is harmful to an organ's development, makes it deteriorate, gradually diminishes it, and finishes by making it disappear, if this lack of use continues for a long time in all the individuals which appear later through reproduction.  From this we understand that when a change in the circumstances compels the individuals of an animal race to change their habitual behaviour, the less used organs little by little waste away, while those which are used more develop better and acquire a strength and dimensions proportional to the use which these individuals routinely make of them.

Secondly, reflecting on the power of movement of fluids in the very supple parts which contain them, I was soon convinced that to the extent that the fluids of an organic body increase their rapidity of movement, they modify the cellular tissue in which they move, open up passages there, form various canals, and finally create different organs, depending on the state of the organic complexity in which they are found.

By following these two considerations, I accepted as certain the fact that the movement of fluids in the interior of animals, a movement which is progressively accelerated with the increasing complexity in organic structure, and the influence of new circumstances, to the extent that animals are exposed to them as they move out into all habitable areas, were the two general causes which have led the different animals to the condition where we see them now....

...I think that the very imperfect animals lacking a nervous system live only with the help of the stimuli they receive from outside.  That is to say, subtle constantly moving fluids contained in the environmental surroundings move continuously into these organic bodies and there sustain life to the extent that the condition of these bodies enables them to do so.  Now, this idea ... was for me a single ray of light which made me see the principal cause which maintains movements and life in organic bodies and to which animals owe everything which gives them life.

By ... combining the ideas about the movement of fluids in the interior of animals and the one about the consequences of a sustained change in the circumstances and habits of these creatures, I was able to grasp the central thread which links up the numerous causes of the phenomena which the developments and the diversity of animal organic structure present to us.  Soon I saw the importance of this method in nature, which consists in preserving in newly produced individuals all the things which the effects of life and environmental influences have produced in the organic structure of those bringing these individuals into existence....

Thus, this Philosophical Zoology presents the results of my studies of animals, their general and particular characteristics, their organic structure, the causes of their developments and diversity, and the faculties they have acquired from it.  To write this work, I have used the major materials which I assembled for a projected work on living bodies, under the title of Biology, a book which, so far as I am concerned, will remain unwritten.

The facts which I cite are very numerous and reliable, and the conclusions which I have derived from them seem to me appropriate and necessary, so that I am convinced that it will be difficult to replace them with better ones.

However, the number of new ideas revealed in this work must naturally, as soon as they are first stated, unfavorably impress the reader, by the sole ascendancy which universally accepted ideas always have over new ones which tend to cast them aside.  Now, since this power of old ideas over those appearing for the first time favours this prejudice, especially when the matter is the least bit interesting, the result is that whatever the difficulties may be in discovering new truths through the study of nature, the difficulties of getting them accepted are much greater still.

These difficulties, arising for different reasons, are basically more of a help than a hindrance for the state of general knowledge.  For because the rigour which makes it difficult to get newly presented ideas accepted as truths, a multitude of odd ideas, more or less specious and without foundation, no sooner appear than they quickly fall into oblivion.  Sometimes, however, some excellent opinions and solid ideas are, for the same reasons, rejected or neglected.  But it is better that a truth, once perceived, fight a long time without obtaining the attention it deserves, than that everything produced by men's keen imaginations be easily accepted.

The more I think about this subject, particularly about the numerous causes which can affect our judgments, the more I am persuaded that, except for physical and moral facts, which no one can call into question, all the rest is nothing but opinion or speculation.  We know that one can always oppose one set of reasons by others.  Thus, although it may be evident that there are great differences in the persuasiveness, probability, and even the worth among the various opinions of men, it seems to me that we would be wrong to blame those who refuse to accept our views.

[NOTE:  I call moral facts the mathematical truths, that is to say, the results of calculations, whether of quantities, forces, or measurements, because it is through intelligence and not by our senses that these facts are known to us.  Now, these moral facts are at one and the same time positive truths, as are facts relative to the existence of bodies which we can observe, as well as others which concern these bodies.]
Must we not recognize as grounded the most universally accepted opinions?  But experience demonstrates well enough that the individuals who have the most highly developed intelligence and who combine the most insights make up at all times an extremely small minority.  There is no way to deny that.  Where matters of knowledge are concerned, the authorities should appreciate the point, and not just judge by numbers, although in truth such appreciation may be very difficult.

However, according to the numerous and rigorous conditions which a judgment requires for it to be a good one, it is still not certain that the judgment of the individuals whom opinion transforms into authorities is perfectly justified concerning the objects on which it delivers its opinion.

There are thus no really reliable truths for human beings, that is to say, things on which they can firmly count, except the facts which they can observe (not the consequences which they derive from them), the existence of nature which presents these facts, as well as the materials to obtain them, and finally the laws which regulate the movements and the changes of nature's parts.  Beyond that, everything is uncertain, although some consequences, theories, opinions, and so on are much more probable than others.

Since it is not possible to count on any chain of pure reasoning, on any conclusions, on any theory, the authors of these intellectual pursuits cannot be certain that they have used there the true elements which must have given rise to it, that they have not allowed in any elements except those and have not neglected any.  There is nothing reliable for us except the existence of bodies which can affect our senses, those real qualities which belong to them, and finally those physical and moral facts which we can know.  Thus, the ideas, the chains of reasoning, and the explanations which one finds revealed in this work must be considered only simple opinions which I propose, with the intention of indicating what appears to me might be the case and what could have really taken place.

Whatever the case may be, in delivering myself of the observations which have given rise to the considerations revealed in this work, I have obtained the pleasures that their resemblance to truths enabled me to experience, as well as the reward for the fatigue attendant on my studies and meditations.  In publishing these results which I have deduced from these observations, I intend to invite insightful people who love the study of nature to follow and verify them, drawing from them in their turn the conclusions which they judge acceptable.

Since this way seems to me the only one which can lead to knowledge of the truth or of what comes closest to it and since it is evident that this knowledge is more advantageous to us than the error which we can put in its place, I cannot doubt that this is the way we must follow....

Preliminary Discourse
Observe nature.  Study her productions.  Carry out research into the general and particular interconnections which she has impressed on their characteristics.  Finally try to grasp the order which she has brought into being everywhere, as well as her progress, her laws, and the infinitely varied ways which she uses to give rise to this order--that is, in my view, to put oneself in a position to acquire the only reliable knowledge at our disposal (the only one, moreover, which can be truly useful to us) and at the same time to gain the sweetest pleasures, those most appropriate to assuage the inevitable pains of life. 

In fact, what is more interesting in the observation of nature than the study of the animals, than thinking about the connections between their structure and that of human beings, about the power which their habits, ways of life, climates, and environments have to modify their organs, faculties, their characteristics, than an analysis of the different structural systems which we see among them and according to which we determine the relationships, some important, others less so, which fix the rank of each one in the natural order.  Finally, what is more interesting than the general arrangement which we establish for these animals, taking into account the greater or lesser complexity in their structures, an arrangement which can lead to an understanding of the very order which nature has followed in bringing each species into existence?...

What is odd is that the most important phenomena to consider have only been available for our reflections since the time when people concerned themselves mainly with the study of the least perfect animals and when research into the different complexities in the structures of these animals became the main basis of their study.

It is no less odd to be forced to acknowledge that it was almost always from the sustained examination of the smallest objects which nature presents to us and from the most apparently minute considerations that we have obtained the most important knowledge for discovering nature's laws and methods and for determining her progress.  This truth, already confirmed by many remarkable facts, will receive new evidence in the matters revealed in this work, and we must be convinced more than ever that, so far as the study of nature is concerned, no object whatsoever is unworthy of attention.

The purpose of the study of animals is not exclusively to understand their different races and to determine all the distinctions among them by establishing their special characteristics.  It is also to reach an understanding of the origin of the faculties which they enjoy and of the causes which brought them into existence and now maintain their lives and, finally, the causes of that remarkable progression which they display in their form and structure and in the number as well as in the development of their faculties....

After having thoroughly studied the organic structures of man, as people have done, rather than fussing about with research into the very causes of life in this structure, the causes of physical and moral sensation, in a word, of the lofty faculties he possess, we then had to try hard to understand the structure of other animals, to consider the differences which exist among them in this respect, as well as the connections which occur between the faculties which are appropriate to them and the organic structure which they have been given.

If these different things had been compared with each other and with what was known concerning man, and if people had taken into account, from the organic structure of the simplest animals right up to that of man, the most complex and the most perfect, the progression manifest in the complexity of the organic structure as well as the successive acquisition of different specialized organs, and consequently of so many new faculties which the new organs bring, then people could have seen how needs, at first reduced to nothing, but then gradually increasing in number, have led to a tendency for actions appropriate to satisfy those needs.  They could have seen how, once these actions became habitual and energetic, they brought about the development of organs which carry them out; and how the force which stimulates organic movements can, in the most imperfect animals, be located outside of them and nevertheless animate them, how later this force was moved and fixed in the animal itself, and finally, how this force has there become the source of sensibility and at last of intelligent action....

I do not acknowledge at all the assumption of such an allegedly universal cause for the real march of nature.  In creating life, she did not start suddenly by establishing such a high faculty as that of feeling.  She did not have the means to bring such a faculty into existence in the imperfect creatures of the first classes in the animal kingdom.

With respect to the bodies which enjoy life, nature made everything gradually and successively; there is no longer any possible doubt about that.

In fact, among the different things which I propose to explain in this work, I will try to reveal, by referring throughout to known facts, that in making animals' organic structures increasingly complex, nature has progressively created different specialized organs as well as the faculties which the animals enjoy.

For a long time it has been thought that there existed a sort of ladder or graduated chain among the bodies endowed with life.  [Charles] Bonnet [1720-1793] developed this view, but he did not prove it by facts derived from organic structure itself; that, however, was necessary, especially in relation to animals.  He could not do it, because at the time he lived people did not yet have the means.

As one studies animals of all the classes, there are plenty of things to see other than the growing complexity in animal organic structure.  The production of causal circumstances leading to new needs, those needs giving rise to actions, those repeated actions creating the habits and inclinations, the results of increased or diminished use of some organ or other, the means which nature uses to preserve and improve everything acquired in the structure, and so on and so on--these are things of the highest importance for rational philosophy

But this study of animals, especially of the less perfect ones, was for a long time neglected; we were so far from suspecting the great interest which it could provide.  And what has been started in this respect is still so recent, that in pursuing it, we have reason to expect many new insights.

When people started truly to cultivate natural history and each kingdom attracted the attention of naturalists, those who directed their research into the animal kingdom studied mainly the vertebrates, i.e., mammals, birds, reptiles, and finally fish.  In these classes of animals, since the species are generally larger, have more developed parts and faculties, and are more easily characterized, they appeared to offer more interesting material to study than those which belong to the division of invertebrate animals.

In fact, the extremely small size of most of the invertebrates, their limited faculties, and the fact that their organs have a much more distant relationship to human ones than the ones we observe among the more perfect animals--these made them, in some ways, commonly despised and, right up to our time, gave them only a very luke warm interest for the majority of naturalists.

However, we are beginning to retreat from this prejudice harmful to the advancement of our knowledge, for in the past few years, when these remarkable animals have been examined attentively, we have been forced to recognize that the study of them must be considered one of the most interesting for the naturalist and the philosopher, because it sheds light onto a number of problems relevant to natural history and animal physics, insight which it would be difficult to obtain in any other way....

[T]he study of invertebrates must be of special interest to the naturalist.  First, the species of these animals are much more numerous in nature than the vertebrate species.  Second, since they are more numerous, they are necessarily more varied.  Third, the variations in their organic structure are much greater, more clear cut, and more peculiar.  Finally, the order which nature uses to form in succession the different animal organs is much better expressed in the mutations which these organs undergo in the invertebrates and makes the study of them much more appropriate for getting us to see the very origin of organic structure, as well as the reason for its complexity and development.  All the issues revealed by the more perfect animals, like the vertebrates, could not achieve this.

Once I was struck with these truths, I felt that, in order to make them comprehensible to my students, rather than burying myself right from the start in details about particular things, I must, above all, present to them the general truths relevant to all the animals, to show them the entire collection, along with the essential considerations pertinent to such a collection.  I proposed after that to grasp the principal groups which seemed to divide up this collection in order to establish comparisons among them and to make the students better understand each one separately.

In fact, the true way to arrive at a full understanding of something, even in its smallest details, is to start by envisaging it in its entirety, by an initial examination, whether of its mass, its extent, or the collection of parts which make it up, by researching what its nature and origin are, what are its connections to other known things, in a word, by considering it from all the points of view which can illuminate for us all the general truths which concern that thing.  Later one divides the object under investigation into its principal parts in order to study them and consider them separately in connection with all those interrelationships which can tell us things about them; and continuing in this way to divide and sub-divide these parts examined in succession, we go right down to the smallest, whose particular details we study, not overlooking the least details.  When all this research is finished, one tries to deduce from it the consequences, and little by little the philosophy of science establishes, corrects, and perfects itself. 

Only by this path can human intelligence acquire the most far reaching, most reliable, and most fully coordinated knowledge in any science whatsoever.  And it is solely by this method of analysis that all sciences make true progress and that the things that they deal with are not confused and can be perfectly understood....

Go to:
  • The Golem, Legends of the Ghetto of Prague;
  • Zoonomia; or, the laws of organic life (1803) by Erasmus Darwin; and
Weekly Readings
Lecture Notes