The Argument of 
Philosophy Zoologique

by Ron Roizen

This paper, which I have edited a little in transferring it to HTML, was originally written for a graduate seminar in the history of science at the University of California, Berkeley in the winter of 1971.

The scene was laid in Paris at the end of the eighteenth and the beginning of the nineteenth centuries.  Voltaire, the libertarian enthusiast, Montesquieu, master political analyst, Rosseau, clockmaker's son and fanatic of freedom, had all died within the generation just passing.  The thought of these three great men had been transformed into action, or so it seemed, by the 'savage dreamers' of the Revolution.  A new era had begun.  Medieval superstition was visibly dissolving at the touch of science.  Had not one daring adventurer a few years before flown into the air in a fire balloon, while another crossed the straits of Dover in a similar contrivance?  Had not Franklin 'brought down the thunder from the clouds'? Had not Lavoisier finally swept away the pretensions of the alchemists and found a new science by splitting up water into two gases?  Still more revolutionary to all previous conceptions was that remarkable new force, electricity, which Galvani and Volta had lately discovered.  To the temper of the times it seemed that nothing was impossible to science.  Man himself might be transformed.  Reason alone was necessary to bring him, the noblest of all creatures, to the perfection that was his birthright....It was a time of hope and enthusiasm for change.  Even the years were no longer to be reckoned by the old method, but from the beginning of the new period of the revolution, and the months were to be known by rational names.
From George Humphrey's Introduction to The Wild Boy of Aveyron by Jean-Marc-Gaspard Itard, first published in 1801.


Does anyone actually read Lamarck anymore?  For most of us, Lamarkian evolutionary theory has been reduced to the bogus example of the giraffe's neck -- which, according to one or another secondary source -- Lamarck believed became elongated over the course of many generations because giraffes liked treetop foliage.  Lamarck stands in the shadow of the theory of natural selection, an historical "before" to Darwin's and Wallace's "afters."  Lamarck's theoretical orientation has also been accused of all manner of shortcomings -- including teleology, anthropomorphism, vitalism, and -- especially in connection with the inheritance of acquired characteristics -- contrariness to fact.

Ah, poor Lamarck!  Philosophie Zoologique, Lamarck's evolutionary masterpiece, runs fully 405 pages in its English translation yet it contains only two sentences specifically about giraffes.  Moreover, only about a third of PZ is devoted to the species problem, and that one-third is not concerned with the nineteenth-century conception of the species problem but with the more sweeping questions of the late Enlightenment.  The book bore the subtitle:

An exposition with regard to the natural history of animals; the diversity of their Organisation and the faculties which they derive from it; the physical causes which maintain life within them and give rise to their various movements; lastly, those which produce feeling and intelligence in some among them.

It was one long argument, badly suited -- even then -- for the extraction and examination of one or another part.  In this paper I will try to treat PZ as a whole. My goal is to clarify Lamarck's evolutionary thinking and place that thought in the larger context of PZ's narrative trajectory.  My approach to this task will consist mainly in reviving and reconnecting the discussion in the third section of Lamark's book -- Lamarck's "psychology," so called -- to the first and second sections.  PZ's argument is long and complicated.  Locating a new perspective on it would be impossible if my account tried to be too detailed.  What follows, therefore, is a barebones outline of the whole of Lamarck's case as it is presented in PZ.

Lamarck was a product of the Enlightenment, one of the new brave band of thinkers whom Carl Becker described as  

...looking out upon a universe seemingly brand new because so freshly flooded with light, a universe in which everything worth attending to is visible, and everything visible is seen to be unblurred and wonderfully simple after all, and evidently lntelligible to the human mind...

Lamarck was at the front guard of the champions of Reason:  he confronted the task of a rational explanation of Reason itself.  M. Cabanis had already argued that there was a perfectly physical explanation of man's higher faculties.  Lamarck was impressed with the problem, though not with the particulars of Cabanis' proof.  

M. Cabanis unquestionably established a very great truth by a series of unexceptionable facts, when he said that the moral and the physical both spring from a common origin; and when he showed that the operations called moral are directly due, like those called physical, to the activity either of certain special organs, or of the living system as a whole; and, finally, that all the phenomena of Intelligence and will take their origin from the congenital or fortuitous state of the organisation. (p. 185)

The problem of Reason was strategically placed: on the one hand vitalists had used the phenomena of sensation, motivated action, and thought as proofs of vitalism. Thus a materialist explanation of thought was helpful to the cause of materialism generally.  On the other hand, the founding of a genuinely materialist philosophy had to await a materialist theory of thought.  Reason, being just another part of nature, had to be understood by natural methods.

For Lamarck, that meant that the zoologist was the one who was most likely to produce an adequate theory of knowledge.  

If the physical and the moral have a common origin, if ideas, thought and even imagination are only natural phenomena, and therefore really dependent on organisation, then it must be chiefly the province of the zoologist, who makes a special study of organic phenomena, to investigate what ideas are, and how they are produced and preserved... (p. 287)

The problem of Reason was at once a case against vitalism, a necessary extension of materialism, and a feather In the cap of zoology. In his "Preliminary Discourse" Lamarck wrote:  

The purpose of the study of animals is not merely to ascertain their different races, nor to determine all the distinctions among them by specifying their special characters. This study further aims at acquiring a knowledge of the functions which animals possess, the causes of the presence and maintenance of life in them, and of the remarkable progression which they exhibit in the complexity of their organisation, as well as in the number and development of their functions.

At bottom, the physical and moral are without doubt one and the same thing. It Is by a study of the Organisation of the different orders of known animals that this truth can be set in the strongest light... (p. 10)

What can the resolute, materialist zoologist bring to the problems of sensation, action, and thought?  Lamarck was convinced that these phenomena could not spring directly from matter, but that they must be consequences (effects) of the organization of matter.  As such Lamarck reasons that sensation, action, and thought must have an organic basis, which is to say (for him) they must be located in a special organ.  The words "organ" and "organisation" are very similar in meaning for Lamarck.  Examine, for example, the following passage:

 If all the acts of the intellect into the causes of which I am now enquiring are only phenomena of nature, that is to say, acts of the organisation, may I not hope, by acquiring a thorough knowledge of the only means by which the organs perform their functions, to discover how the intellect may give rise to the formation of ideas and preserve their traces or impressions for a longer or shorter period and finally by means of these ideas, carry out thought, etc., etc.?  (p. 287-288)

The conviction that every faculty must have an organ recurs throughout the book: 

These remarkable facts no longer surprise us, when we recognise that every faculty is based upon some special organ or system of organs...  (p. 49)

I venture to affirm that where there is no organ for a faculty, that faculty cannot exist.  (p. 365)

It would be an easy matter to multiply these examples.  The tie between organs and faculties is important to Lamarck for a number of reasons.  First, it provides a bridge between the worlds of philosophy and natural history.  Second, the study of organs provided Lamarck with a route around one of the most difficult obstacles to a materialist explanation of thought.  Physiologists had long observed that nature had followed the same basic plan in the production of her creatures.  They had the same organ system, which merely diminished in clarity of differentialtion as one examined simpler and simpler animals.  Both the better knowledge of and the faddish attention to higher animals, mammals in particular, had led to the presumption that life was everywhere made from the same mold.  Also, the functionalist premise that the organ system of mammals was a statement about what was necessary to sustain life had led physiologist to look for a similar, if simplified, organization in all animals.  The presumption of physiological continuity among nature's productions was not entirely anathema to Lamarck's case, but it did present one outstanding problem -- why, given nature's physiological continuity, did not each of nature's creatures exhibit the moral abilities of men?  Or, put negatively, how can man's intelligence be explained zoologically, when, zoologically speaking, he is not significantly different from not only his nearest animal relatives but not different in kind from even rather simple creatures?  To prove that mind has a physical basis Lamarck had to prove that "mindless" creatures also lack the organ of mentation.  Necessary to such a proof is the more general proof that all life does not require the same organization.

But Lamarck had to take care that he did not throw out the materialist baby with the bath water.  If new organs -- that is, physiological discontinuities -- are to account for new faculties, they must be new organs that can be gotten from simpler animals free of any supernatural intervention or vitalist causes.  Too great a discontinuity threatens his larger arguments.  Thus Lamarck walked a tightrope, at once concerned with the new powers of more perfect organization and the natural origins of these new organs.

Lamarck's discussion of organs and their progress has been frequently interpreted as his way of talking about species.  It is clear from the second and particularly the third parts of the book that this interpretation is faulty.  Lamarck's case rests an the problem of the introduction of new organs, not on the the introduction of new species.  We shall examine later as how this difference will modify our interpretation of Lamarck's taxonomic and "evolutionary" statements in the first part of the book.

The whole of the materialist case must fall within the conceptual limits of the materialism of the early 1800s. Thus Lamarck has matter, motion, organization, and an array of visible and subtle fluids at his disposal.  Equally important to Lamarck is the condition that nature must do everything gradually. The introduction of discontinuities and catastrophes is little more than a cover for our ignorance, wrote Lamarck. He repeated throughout the book the necessity of the gradualness of nature.  But it is repeated not only on behalf of materialism per se.  "If we do not carefully note the gradual order followed by nature in the creation of the various animal faculties," Lamarck wrote, "I believe that we shall find it hard to explain how she could have brought feeling into existence, and still harder to conceive how simple relations between material substances can give rise to thought" (pp. 344-345).

It is not obvious, however, either to Lamarck or other students of natural history, that nature has gradually introduced more perfected animals.  It would have been ideal for Lamarck's purposes if the array of living creatures had formed one continuous line from monads to men, but they did not.  Naturalists, moreover, had fixed the discontinuities among the products of nature in an elaborate system of taxonomy, and system had been mistakenly interpreted as a product of nature instead of a merely artificial device of man.  Given the unmanageable array of nature's productions how can we grasp the essential continuity and gradualness of the production of organs?  Lamarck argues that where species have been extensively studied, they tend to form a linear arrangement in which it is impossible to interpose sound specific lines.  If we are to catch the continuity of nature before the complete discovery of all natural species, however, Lamarck must employ a method by which tease it out of nature. And that is what he does.

Firmly based on the assumption of the gradualness of nature, Lamarck confronts the fact that nature has not presented a smooth linear progression of organizations. Since nature must work smoothly, Lamarck asks why the known array of creatures appears to be very diverse and discontinuous.  Incomplete knowledge is part of the problem, writes Lamarck, but there is a more important cause:  

If the factor which is incessantly working towards complicating organisation were the only one which had any influence on the shape and organs of animals, the growing complexity of organisation would everywhere be very regular.  But it is not; nature is forced to submit her works to the influence of their environment, and this environment everywhere produces variations in them.  This is the special factor which occasionally produces in the course of the degradation...the often curious deviations that may be observed in the progression.  (p. 69)

Lamarck argues that the use and disuse of organs, prompted by the variation in environments has caused what would have been smooth and continuous to appear to be discontinuous.  His problem, therefore, is that of rediscovering the simple series, that was, indeed, nature's order for the introduction of new organizations.  He makes the heuristic assumption that there is an underlying linearity to nature, and that assumption becomes the instrument for discovering something of the order, and the method by which nature produced new organs.  

I do not mean that existing animals form a very simple series, regularly graded throughout; but I do mean that they form a branching series irregularly graded and free from discontinuity or at least once free from it.  (p. 37)

Lamarck is after the big picture.  He concentrates therefore on the arrangement of classes (mammals, birds, etc.) on his linear model.  He is also convinced that affinities among species, rather than differences, must be the guiding criteria for his arrangement.  Affinities must be determined, however, with respect to organs that are not subject to modification due to environmental changes.  It is these modifications, after all, that have blurred the picture in the first place.  

Among animals whose affinities are mainly determined by their internal organisation, three kinds of special organs have rightly been been chosen from among the others as the most suitable for disclosing the most important affinities.  They are, in order of importance, as follows:

(1) The organ of feeling.  The nerves which meet at a centre, either single as in animals with a brain, or multiple as in those with a ganglionic longitudinal cord.
(2) The organ of respiration.  The lungs, gills and tracheae.
(3) The organ of circulation.  The arteries and veins, which usually have a centre of action in the heart.  (p. 31)

Everything is falling into place nicely for Lamarck, The faculties of sensation, action and thought are what he wishes to account for.  In the process of accounting for their natural origins, he has engineered a taxonomy that employs the organs of feeling as the most important test.  It is relatively easy for Lamarck to identify the ends of his heuristically linear scale: at the top is man and at the bottom are infusoria, the simplest one-cell animals.  He flashes his Enlightenment colors in this scale:  "It is...known that perfection of faculties is a proof of perfection of the organs on which they rest" (p. 71).

But two ends does not make a scale of nature.  How is Lamarck to discover and report the main perfections of nature on a tree that has been everywhere branched by the necessities of the environment?  It is the trunk of that tree that Lamarck wishes to follow, free of the distractions that raw nature can present.  An analogy has helped me to understand the manner in which Lamarck proceeded.

Suppose you are an ant wishing to find the shortest route between the top and the bottom of an irregularly upward branching tree.  If you start at the. bottom, you will be faced with a decision at each branch:  which direction is the main line?  But if you start at the top, you must only keep going down, dead-end detours will be avoided.  For similar reasons, Lamarck began with man and attempted to follow the course of "degradation" in nature,

Descending that trunk, Lamarck has only to watch for the diminution and, ultimately, disappearance of the organs which he has decided to be critical.  The phantasmagoria of species has been transcended by this simple device.  The exercise, disregarding its circularity for the moment, could not have been more successful.  Lamarck finds fourteen natural classes which can be collapsed into six stages of development. These are:  

6th Stage.  Nerves terminating in a brain which fills the cranial cavity; heart with two ventricals; and the blood warm.

5th Stage.  Nerves terminating in a brain which is far from filling the cranial cavity; heart with one ventrical, and the blood cold.

4th Stage.  Nerves terminating in a brain or a ganglionic longitudinal cord; respiration by gills; arteries and veins for circulation.

3rd Stage.   Nerves terminating in a ganglionic longitudinal cord; respiration by air carrying tracheae; circulation absent or imperfect.

2nd Stage.  No ganglionic longitudinal cord; no vessels for circulation; a few internal organs in addition to those of digestion.

1st Stage.  No nerves; no vessels; no specialised internal organ except for digestion.*  (pp. 131-133)

Lamarck's introduction of the spine as a taxonomic device sprang from this ground.  But more importantly Lamarck's problem was now half-solved.  By gently reshuffling nature in his system of classification, he had drawn an unbroken line between the infusoria and man in so far as the organs of sensation, action, and thought were concerned.  So successful did Lamarck regard his classificatory enterprise that he was moved to write: solid grounds can ever be found for changing the general features of this classification, though changes may be made as to detail, particularly in the divisions that are subordinate to the classes; because the affinities between the objects comprised in the sub-divisions are more difficult to determine and leave more to arbitrary opinion.  (p. 133)

Sensation, action, and thought have not yet been explained. Nor has the engine in nature that produces new organs in a continuous series.  But once explained, these phenomena shall have the backing of a smoothly continuous origin.  If new organs can account for moral phenomenal, these new organs will be full-fledged products of the gradual and continuous methods of nature, requiring no supernatural or vitalist impositions.

Before leaving the subject of origins, it is appropriate to comment briefly on Lamarck's theory of inheritance.  It is well known that Lamarck believed that acquired characteristics were passed on to the next generation.  I shall argue here that Lamarck meant this conclusion in a way that is quite different from the way in which it is nowadays ordinarily interpreted.

Chapter VII of the first part of PZ is titled, "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 Organisation and structure."  Therein, on page 113, Lamarck presents his two laws of environmental influence.  It should be remembered that the entire discussion of environmental influences is necessary because nature appeared to be too various to be subsumed under one linear progression.  The law or at least the first law, are explanations of the error around Lamarck's model, not the substance of the model itself.  The first law was:  

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.

The second,  

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.

The balance of the chapter is devoted to proofs of the effects of use and disuse on organs.  The second law is not discussed, nor is it discussed anywhere else in the book.  At first I found this omission surprising.  Wherever Lamarck mentions the inheritance of acquired characteristics he treats it as a self-evident fact, requiring no proof or discussion.  The reason he ignores inheritance, however, is straightforward.  For Lamarck the idea of the inheritance of acquired characteristics is nothing more than a corollary to the gradualness of nature.  Lamarck has arranged creatures on a scale from the simplest to the most perfect.  The more perfect creatures, he believes, must have been produced from simpler ones.  Thus, a mouse is the culminating product of generations of life in which organization was slowly made more complex and more perfect.  The mouse, when it bears young, bears more mice.  Hence nature has preserved in the new mice all of the organizational perfection.

It is in that sense that Lamarck took for granted the capacity for the parental generation to pass on complexity to offspring -- in effect, "the inheritance of acquired characteristics."  Only if mice produced infusoria or other lowly animals would Lamarck concede that nature did not "preserve" her advances in organization.  Even from a Darwinian perspective Lamarck's conclusion is unassailable.  Any animal, because it started out as a much simpler species represents a capacity in nature to maintain the complexity of its species.  Thus animals are the product of "the inheritance of acquired characteristics" in so far as much was acquired, in one way or another, in the course of organic evolution.

Lamarck, it must be remembered, was a matter-and-motion man.  Given that mice can accomplish the enormous feat of the transmission of their own level of organization to their progeny, it is hardly a problem for Lamarck to conclude that this accomplishment preserved organizational gains in every case of an incremental advance in rodent organization.  For Lamarck there is hardly an alternative.  The proof of the inheritance of acquired characteristics -- in the broad sense in which it is here interpreted -- is visible in the progeny of every somewhat perfect creature.

But how is a new organ created?  So far Lamarck has merely shown that species are ordered in terms of the development of their organs of sensation and that there appears to be a relatively smooth progression in those organs.  Thus Lamarck has shown that the progressive development of sensational organs is not at odds with a "natural" system of classification.  The classification system, however, is not an explanation of progressive development, nor is it an account of how matter can indeed, carry out the phenomena of sensation, actions and thought.  We are asking a great deal of Lamarck.  The theory of natural selection does not give a positive account of the origins of new organs; it tells us only that nature eliminated creatures that could not compete with others who had them.  Indeed, one commentator has observed that  

However absurd this may seem, it must be admitted that unlimited time having been once granted for organs to be developed in series of generations, the objections to their being formed in a the way here imagined [he is speaking of Lamarck, R.R.] are only such as equally apply to the theory of mm their origin by natural selection....Darwinian theory is equally helpless to account for the beginning of a new organ, wile it demands as imperatively that every stage in the assumed heredity development of an organ must have been useful.  (Packard, pp. 354-355)

The problem of new organs is the problem of the second section (not the first section) of PZ.  Before we examine Lamarck's proposed solution, I would like to make two prefatory comments:

First, Lamarck will use "subtle fluids" in his explanation.  To the twentieth-century eye these fluids look suspiciously like spiritualist placeholders, only barely removed from outright vitalism.  But Lamarck's subtle fluids are quite real in the context of the physics of the early 1800s.  The Leyden Jar, after all, was a jar because electricity was fluid and one keeps fluids in jars.  Lamarck was appealing to the physics, not the metaphysics, of his time.  He could no more ignore these fluids than we would ignore the radiation warning on a laboratory door,

Second, Lamarck was of course, well acquainted with cells; and he saw them, in a sense, as the building blocks of life.  Yet some of his ideas about cells may sound quite odd.  It is important to recall that the conception of cells in this period was decidedly compartmentalist rather than internalist -- that is, the cell of 1800 was mostly a biological container of interest because it formed the structure of living tissue.  Years must pass before the walls of the cell fade and the contents become conceptually central.  With these warnings in mind, let us examine Lamarck's account of new organs.

Always lurking in the wings is Lamarck's conviction that if moral phenomena are to be explained zoologically (that is, materialistically), then significant zoological differences between higher and lower creatures must be established.  These differences, moreover, must be tied to parallel differences in intellectual abilities.  Of particular importance to the second part of PZ is the problem of sensation.  Lamarck's empiricist comrades had placed him in an embarrassing position.  Locke, Bonnet, and Condillac, in their enthusiasm for the replacement of Platonic idealism with brute sensations in the scheme of knowledge, had gone so far as to claim that sensation was the very essence of life.  But ceding the faculty of sensation to all living beings would irreparably skew the parallelism between organs and faculties that Lamarck wished to establish.  In the progression from simple to perfect beings, the faculty of sensation constituted a positive gain in organization -- one that required and was reflected in the development of a new organ.  Were plants and the simplest animals capable of sensation, the organ-faculty case would be much threatened.  Lamarck defended his parallelism at each step of the way, and he was obliged, therefore, to invest the simplest living creatures with as little as possible in the way of neurological abilities.  Much of the discussion in part two, consequently, is pivoted on a polemic that is not inherently necessary to Lamarck's general case.

We are interested in Lamarck's theory of the origin of (now) organs.  He directs our attention to simple creatures rather than complex ones on the grounds that it should be easier to comprehend the nature of organs where there is less complexity.  The organs of mammals are not essential to all life, but merely to the life of mammals.  To understand how life produces organs Lamarck believes that it is best to start at the beginning.

Before we can understand organs, we must have an adequate understanding of and definition of life.  In the first chapter of part two, Lamarck listed ten distinguishing characteristics of living things.  He then proceeded to compare plants and animals for their significant similarities and differences. From this exercise Lamarck concluded that nothing alive could be completely dry and that every living thing had cellular containing parts.  That which was contained in these parts, moreover was always in motion,  

Seeing that life in a body results exclusively from the relations existing between the containing parts in an appropriate condition the contained fluids moving in them, and the exciting cause of the movements activities, and reactions which take place we may include what essentially constitutes life in the following definition.

Life, in the parts of any body which possess it, is an order and state of things which permit of organic movements; and these movements constituting active life result from the action of a stimulating cause which excites them.  (p. 202)

Lamarck used a modified analogy with a watch.  The cellular containers and the contained fluids were like the internal organization of the clock.  They represented an organizational preparedness to go into action once the influence of an organic spring was added.  Unlike the watch, however, the living cell did not contain its own spring. 

We have seen that life is a natural phenomenon...and that it results from the relations existing between the supple containing parts of an organised body and the contained fluids of that body.  We cannot conceive the production of this phenomenon, that is to say, the presence and continuance of the movements constituting active life, unless we imagine a special exciting cause of these movements, a force which animates the organs, controls the activities and all the organic functions, -- a spring, in short, of which the permanent though variable tension is the driving energy of all vital movements.  (p. 211)

In hindsight, all this makes perfect sense; without a rich internalist picture of cells that features metabolisis, the natural place to look for the source of the action was outside the cell.  The ready-and-waiting idea of cell structure was supported by a number of observations -- most notably, the rotifers of Spallanzani.  Spallanzani had alternately drained and immersed in tepid water a rotifer.  When drained, the rotifer looked dead, but when immersed, it resumed life.  For Lamarck, this experiment  

...shows that life can be alternately suspended and renewed: it is therefore only an order and state of things in a body by means of which vital movements can occur when stimulated by a special cause.  (p. 203)

What, then, drove the cell?  The ancient philosophers "felt the necessity for a special exciting cause of organic movements;" wrote Lamarck,  

but not having sufficiently studied nature they sought it beyond her, they imagined a vital principle, a perishable soul for animals, and even attributed the same to plants; thus in place of positive knowledge, which they could not attain from want of observations, they created mere words to which are attached only vague and unreal ideas.  (pp. 211-212)

Rather than invoke these fantasies Lamarck called upon the "subtle, invisible, uncontainable, incessantly moving fluids" that had only recently become legitimate scientific phenomena.  These fluids would have been no better than spirits save for the fact that they revealed themselves in many well-known and perfectly empirical ways.  Caloric, electric, and magnetic fluids, moreover, had ideal properties.  The first was " invisible penetrating, expansive everactive fluid that percolates slowly through the supple parts, distending them and making them irritable; and that is constantly being dissipated and renewed and is never entirely absent from any body that possesses life..." (p. 218).  The second, electricity, was fast and powerful.  These fluids were adequate for Lamarck; and they were sufficiently real for him to claim, for example, that electricity was introduced in animals through the medium of respiration or of food" (p. 214).

Sunlight was Lamarck's ultimate source of these energies.  It was in terms of the contained jelly and the containing cell that Lamarck distinguished plants and animals:  in plants the jelly but not the cell wall was excited by fluids; in animals both jelly and wall were excited.

Most importantly, these new fluids have provided Lamarck with a developmental engine.  Their eddies create pathways and deposits in simple creatures -- i.e., proto-organs.  Under the radiations of these fluids, the cellular jelly also becomes a living laboratory in which these excitations produce and destroy all of the possible combinations and recombinations of matter.  Given the box-conception of cells, the fundamental nature of advanced organs is confined to the channels that these fluids can ultimately create.  Combination and complexification in the jelly gives rise to growth and diversity.  Growth, in turn, creates new problems for the organism -- chief among these being the problem of adequate maintenance of a threshold level of motion in all of the parts.  Primitive muscles, whose function is to shake up the flagging jelly, are generated.  Once formal, if simple, organs appear, the exigencies of use and disuse begin to be felt.  The fact of highly perfected creatures suggests that the vital fluids must have been animalized in the cellular laboratory.  Consequently, they became containable, and thereby deliverable to the needful parts of increasingly complex bodies.  Blood, which is rich and complex, is a far cry from the limp fluids of simple creatures -- a fact that speaks for animalization.

All this may sound rather fantastic.  In fairness to Lamarck I should point out that this overbrief summary loses much of the step-by-step rigor of the case as it is presented by Lamarck himself.  There are two other qualifying remarks that should be made:

There is a latent teleological cast to Lamarck's case as it is summarized above.  Nature, if not simple animals, seems to will itself perfection.  Lamarck speaks of the function of fluids as being the carving out of routes, for example.  Yet, when reading the original, one gets no sense of tacit teleology.  Skin or bark, for example, are regarded as the inevitable consequence of the opposing pressures of the inside and outside of living bodies.  Part of the source of the mechanist-teleologist ambiguity is stylistic.  Lamarck seems to attempt to make more vivid the tale of organic perfection by reporting -- on-the-spot, if you will -- the actual directions that life has taken.  What is conceptually important to Lamarck, however, is that he has introduced a fount of vital activity and change.

My second "qualifying remark" is purely impressionistic.  It is difficult to distinguish modesty from false modesty in PZ.  But I get the impression that Lamarck was primarily interested in the establishment of the conceivability of a materialist explanation of vital and moral phenomena.  In several passages he wrote that a complete understanding of life was distant.  Thus he allowed himself the ballpark margin that is allowable to those who argue only about what could be or how things could have happened.  He assumed that a loose speculative approach to a fundamental set was preferable to a rigorous blindness (Goffman),  especially when that blindness left such questions in the hands of supernaturalists.  Even on so basic a matter as the truth of the hypothesis that caloric and electricity are the exciting causes Lamarck cautioned his reader that he had  no way of being certain.  All that mattered, wrote Lamarck, was that these kinds of fluids appeared to have the kinds of qualities that would excite life.  Perhaps in the back of Lamarck's mind was the hunch that when the vitalist-mechanist debate became a toss-up the rhetorical advantage would flow against vitalism.

The question of origins had now been solved; Lamarck had also shown that the same organs are not universally required for life.  Containing parts, contained jelly, and subtle fluids were the mechanism and the spring of life.  

It is from the uninterrupted co-operation of these factors and of long periods of time, combined with an infinite variety of environments that all the orders of living bodies have been successively formed.  (p. 233)

We move now to Lamarck's explanation of feeling and the more sophisticated moral phenomena.

Blood is imported seawater.  When living creatures first dragged themselves onto dry lands it was portable seawater -- blood -- that kept their living tissues bathed in life-giving saline.  A corresponding case is made for nervous fluid by Lamarck.  Life, at the outset, is the passive subject of the whirls and eddies of environmental caloric and electric fluids.  

Now, Nature has wrought her various productions by slow and gradual stages; she had created the various organs of animals in turn, varying the shape and situation of these organs according to the circumstances and progressively improving their faculties, Hence we feel that she must have begun by borrowing from without, that is, from the environment, the force which produces the organic movements and those of the external parts that she afterwards transferred that force within the animal itself, and that finally, it the most perfect animals she made a great part of that internal force available to their will... (p. 344)

Lamarck, in the third section of PZ unfolded his carefully prepared organ-faculty synomorphism.  He observed, at the beginning of his argument in this section, that the nervous system of higher animals was not a unitary but a compound system; this system, moreover, confers upon higher animals three separate abilities:  first, muscular movement; second, feeling and volitional (but instinctive) action; and finally, will and intellect.  These three abilities are cumulative in the sense that creatures with intellect also have the two lesser abilities while simple creatures may have none or only the first ability (muscular movement).  Without a nervous system, none of the above abilities are had.  Plants and the simplest animals, therefore, lack any muscular movement or volition.  In the case of plants, the containing parts are biotically inert:  the environmental fluids, therefore, provide excitation for the contained fluids only.  Thus, for Lamarck, plants are not truly irritable -- irritability being the first sensory faculty.  Simple animals, on the other hand, have containing walls that are capable of fast and repeated contractions or other movements.  These movements -- or more particularly, their speed -- indicate the susceptibility of the walls themselves to fluid influences. But, cautioned Lamarck, we should not impute too much to these movements.  They are only apparently the result of volition. No feeling or intent produces them.  They are the consequence of the fluid ambiance, nothing more.

Referring to his heuristically linear scale, Lamarck moves  next to animals with simple ganglia but without a main medullary mass.  In this group animals are capable of routing the fluid to muscles, which, then, contribute to the movement level ot the whole organism.  But this ability involves no sensation, will, or intellect.  That muscular movement does not necessarily imply sensation is demonstrated in several ways by Lamarck.  The simplest of these demonstrations is the fact that one does not necessarily fee one's legs when one walks.

Next an the evolutionary ladder are creatures with a medullary mass -- a true brain, Lamarck calls it.  With the arrival of a brain or a central reservoir of nervous fluid, nature has created the power of sensation.  The explanation of sensation is certainly the watershed point in Lamarck's explanation of moral abilities:  it is the first phenomenon that cannot be a property of matter alone.  There is wonder in Lamarck's opening lines to his chapter on sensation:  

How are we to conceive that certain parts of a living body can  possess the faculty of feeling, when no kind of matter whatever does or can enjoy any such faculty! (p. 321)

Convinced that every faculty must have an appropriate organ, Lamarck argued that the capacity to experience sensations must be associated with an organ that is the sensorium.  The brain is that organ.  But here Lamarck must confront a difficult problem:  when we say "my finger hurts," that statement implies that the hurting is located in the finger.  The anatomical constituents of a finger, therefore, might be all that is necessary for the creation of sensation.  The notion that a finger alone has the capacity to feel is part of the reason for the ascription of sensibility to all animals, simple or complex.  A lone finger is not necessarily more complex than, say, a whole ant.  Hence, the ant may be ascribed with all of the capacities of that finger.  This is a costly ascription, however, wrote Lamarck, leading to a false understanding of sensation and the other moral faculties.  It is Lamarck's objective in Chapter III of the third section of PZ to establish the fact that sensation is not located in the finger but in the creature as a whole.  That is, the sensation does not take place in the finger but in the entire nervous system and in such a way that the origin of the sensation can nevertheless be associated with the (finger) point of origin.  Lamarck's route around this problem is quite simple:

He argued that the nervous system is stimulated at one point.  This stimulation is transmitted to the central reservoir through the nerves.  There, like any other ripple, this transmission continues out the entire nervous system to all of the tributary end points.  At the nerve ends this internally received ripple is reflected back to the sensorium. The original nerve, however, sends back no reflected ripple, Consequently, the entire accumulated ripple-of-reflection is channeled into the nerve of origin.  Hence, w experience a pain in our finger, by the action of the whole system.  The pain in one's finger is not the product of digital anatomy, but the consequence of the entire nervous system.

The brain however is not capable of thought or will, at this points.  Rather it is the agent of what we would today call reflex actions.  Animals with brains do experience their existence  -- or possess what Lamarck has called "inner feeling.''  This "inner feeling" has been variously translated and interpreted by various students oft Lamarck.  Packard for example chooses to translate it as "consciousness."  But the appropriate meaning of Lamarck's phrase is, in my opinion, much more limited.  For Lamarck this "inner feeling" is the consequence of the containability of previously exterior fluids.  Thus it is a sort of outside-on-the-inside feeling -- the capacity to experience as an internal sense something that is almost external in a topological way.  The brain is the anatomical vessel of this inner feeling.  Therein the needs of the organism are translated into habitual actions whose ends meet or satisfy those needs.  No thought takes place.

Thought, which is the last perfection of nature, has its own organ:  the hypocephalon.  The hypocephalon comprises  the two wrinkled hemispheres that appear atop the "brain" (medulla) in nature's highest creatures.  Here the sensations of the brain are transmitted and stored.  Thought, which always is a form of comparison or the act of making relationships, is achieved by the splitting of a sensation. These split sensations are passed through the circuits of the hypocephalon, such that they encounter and incorporate the collected impressions of past experience.  The variability of judgments from person to person is solely a product of the great variability in stored impressions and sensations.  Once a sensation has made loops into the hypocephalon, the output is rejoined and a thoughtful action is made possible.

This section of the book should be more completely examined here   What is important for my purposes,  however, is the integral quality of these hypotheses. Sensation is the product of a special organ -- the nervous system with a brain; that organ is the product of a natural evolution of organs; organs develop by the effects of the life force upon the arrangement of supple tissue; these effects could be obvious but for the variety of creatures that the environment has necessitated, etc., etc.

I think that the flattening of Lamarck's case -- that is, the revitalization of and reconnection of the material of the third section is a necessary prolegomenon to an historical understanding of Lamarck.  Lamarck had propounded a system of nature -- one that touched virtually every major problem of the science of 1800.  He everywhere suggested novel and in some cases rather modern analyses of natural processes.

I was struck by the fact that Elliot translated "Philosophie Zoologique," as it appeared in the first sentence of the book, as "Philosophical Zoology" rather than "Zoological Philosophy."  Even given that there are difficulties in the latter translation, the fact that Lamarck has been twisted by post-Darwinian readers should be abundantly clear.  Lamarck was on the front guard of materialism, not zoogeography.

I would like to make one final comment.  In the end one gets the definite sense that Lamarck's effort in PZ came to an end that was for him rather melancholy.  Once explained zoologically, the light of reason took on for him a rather contingent luminescence.  While he wrote the book as a crowning piece for rationalism and materialism in the best Enlightenment spirit, his substantive comments on philosophy are always conditional and rather disparaging with regard to the powers of reason.  That which was to be the general conquests of and for Reason had inexorably thrust upon Lamarck an untimely relativism and philosophically congenital doubt.  One can almost hear in him the words that Charles Darwin wrote to W. Graham approximately 72 years later:  

...nevertheless you have expressed my inward conviction...that the Universe is not the result of chance.  But then the horrid doubt always arises whether the convictions of man's mind, which has been developed from the mind of the lower animals, are of any value or at all trustworthy.  Would any one trust in the convictions of a monkey's mind if there are any convictions in such a mind? (Life & Letters, Vol. 1, p. 285)