Dialectics of Nature. Frederick Engels 1883

Notes and Fragments

Source: Dialectics of Nature, pp. 243-256;
First Published: by Progress Publishers, 1934, 6th printing 1974;
Translated: from the German by Clemens Dutt;
Transcribed: by Andy Blunden, 2006.

[Forms of Motion of Matter, Classification of the Sciences]

Causa finalis – matter and its inherent motion. This matter is no abstraction. Even in the sun the different substances are dissociated and without distinction in their action. But in the gaseous sphere of the nebula all substances, although separately present, become merged in pure matter as such, acting only as matter, not according to their specific properties.

(Moreover already in Hegel the antithesis of causa efficiens and causa finalis is sublated in reciprocal action.)

* * *

Primordial matter.

“The conception of matter as original and pre-existent, and as naturally formless, is a very ancient one; it meets us even among the Greeks, at first in the mythical shape of chaos, which is supposed to represent the unformed substratum of the existing world.” (Hegel, Enzyklopädie, I, p. 258.)[193]

We find this chaos again in Laplace, and approximately in the nebula which also has only the beginning of form. Differentiation comes afterwards.

* * *

Gravity as the most general determination of materiality is commonly accepted. That is to say, attraction is a necessary property of matter, but not repulsion. But attraction and repulsion are as inseparable as positive and negative, and hence from dialectics itself it can already be predicted that the true theory of matter must assign as important a place to repulsion as to attraction, and that a theory of matter based on mere attraction is false, inadequate, and one-sided. In fact sufficient phenomena occur that demonstrate this in advance. If only on account of light, the ether is not to be dispensed with. Is the ether of material nature? If it exists at all, it must be of material nature, it must come under the concept of matter. But it is not affected by gravity. The tail of a comet is granted to be of material nature. It shows a powerful repulsion. Heat in a gas produces repulsion, etc.

* * *

Attraction and gravitation. The whole theory of gravitation rests on saying that attraction is the essence of matter. This is necessarily false. Where there is attraction, it must be complemented by repulsion. Hence already Hegel was quite right in saying that the essence of matter is attraction and repulsion.[194] And in fact we are more and more becoming forced to recognise that the dissipation of matter has a. limit where attraction is transformed into repulsion,. and conversely the condensation of the repelled matter has a limit where it becomes attraction.

* * *

The transformation of attraction into repulsion and vice versa is mystical in Hegel, but in substance he anticipated by it the scientific discovery that came later. Even in a gas there is repulsion of the molecules, still more so in more finely-divided matter, for instance in the tail of a comet, where it even operates with enormous force. Hegel shows his genius even in the fact that he derives attraction as something secondary from repulsion as something preceding it: a solar system is only formed by the gradual preponderance of attraction over the originally prevailing repulsion. – Expansion by heat=repulsion. The kinetic theory of gases.

* * *

The divisibility of matter. For science the question is in practice a matter of indifference. We know that in chemistry there is a definite limit to divisibility, beyond which bodies can no longer act chemically – the atom; and that several atoms are always in combination – the molecule. Ditto in physics we are driven to the acceptance of certain – for physical analysis – smallest particles, the arrangement of which determines the form and cohesion of bodies, their vibrations becoming evident as heat, etc. But whether the physical and chemical molecules are identical or different, we do not yet know.

Hegel very easily gets over this question of divisibility by saying that matter is both divisible and continuous, and at the same time neither of the two,[195] which is no answer but is now almost proved (see sheet 5,3 below: Clausius).

* * *

Divisibility. The mammal is indivisible, the reptile can regrow a foot. – Ether waves, divisible and measurable to the infinitesimally small. – Every body divisible, in practice, within certain limits, e.g., in chemistry.

“Its essence (of motion) is to be the immediate unity of space and time ... to motion belong space and time; velocity, the quantum of motion, is space in relation to a definite time that has elapsed.” ([Hegel,] Naturphilosophie, S. 65.) “... Space and time are filled with matter.... Just as there is no motion without matter, so there is no matter without motion.” (p. 67.)[196]

* * *

The indestructibility of motion in Descartes’ principle that the universe always contains the same quantity of motion.[197] Natural scientists express this imperfectly as the “indestructibility of force.” The merely quantitative expression of Descartes is likewise inadequate: motion as such, as essential activity, the mode of existence of matter, is indestructible as the latter itself, this formulation includes the quantitative element. So here again the philosopher has been confirmed by the natural scientist after 200 years.

* * *

The indestructibility of motion. A pretty passage in Grove – p. 20 et seq.[198]

* * *

Motion and equilibrium. Equilibrium is inseparable from motion. [In margin: “Equilibrium=predominance of attraction over repulsion."] In the motion of the heavenly bodies there is motion in equilibrium and equilibrium in motion (relative). But all specifically relative motion, i.e., here all separate motion of individual bodies on one of the heavenly bodies in motion, is an effort to establish relative rest, equilibrium. The possibility of bodies being at relative rest, the possibility of temporary states of equilibrium, is ‘the essential condition for the differentiation of matter and hence for life. On the sun there is no equilibrium of the various substances, only of the mass as a whole, or at any rate only a very restricted one, determined by considerable differences of density; on the surface there is eternal motion and unrest, dissociation. On the moon, equilibrium appears to prevail exclusively, without any relative motion-death (moon=negativity). On the earth motion has become differentiated into interchange of motion and equilibrium: the individual motion strives towards equilibrium, the motion as a whole once more destroys the individual equilibrium. The rock comes to rest, but weathering, the action of the ocean surf, of rivers and glacier ice continually destroy the equilibrium. Evaporation and rain, wind, heat, electric and magnetic phenomena offer the same spectacle. Finally, in the living organism we see continual motion of all the smallest particles as well as of the larger organs, resulting in the continual equilibrium of the total organism during the normal period of life, which yet always remains in motion, the living unity of motion and equilibrium.

All equilibrium is only relative and temporary.

* * *

(1) Motion of the heavenly bodies. Approximate equilibrium of attraction and repulsion in motion.

(2) – Motion on one heavenly body. Mass. In so far as this motion comes from pure mechanical causes, here also there is equilibrium. The masses are at rest on their foundation. On the moon this is apparently complete. Mechanical attraction has overcome mechanical repulsion. From the standpoint of pure mechanics, we do not know what has become of the repulsion, and pure mechanics just as little explains whence come the “forces,” by which nevertheless masses on the earth, for example, are set in motion against gravity. It takes the fact for granted. Here therefore there is simple communication of repelling, displacing motion from mass to mass, with equality of attraction and repulsion.

(3) The overwhelming majority of all terrestrial motions, however, are made up of the conversion of one form of motion into another – mechanical motion into heat, electricity, chemical motion – and of each form into any other; hence either the transformation of attraction into repulsion – mechanical motion into heat, electricity, chemical decomposition (the transformation is the conversion of the original lifting mechanical on into heat, not of the falling motion, which is only the semblance) [ – or transformation of repulsion into attraction].

(4) All energy now active on the earth is transformed heat from the sun.[199]

* * *

Mechanical motion. Among natural scientists motion is always as a matter of course taken to mean mechanical motion, change of place. This has been handed down from the pre-chemical eighteenth century and makes a clear conception of the processes much more difficult. Motion, as applied to matter, is change in general. From the same misunderstanding is derived also the craze to reduce everything to mechanical motion – even Grove is

“strongly inclined to believe that the other affections of matter ... are, and will ultimately be resolved into, modes of motion,” p. 16 [200]

which obliterates the specific character of the other forms of motion. This is not to say that each of the higher forms of motion is not always necessarily connected with some real mechanical (external or molecular) motion, just as the higher forms of motion simultaneously also produce other forms, and just as chemical action is not possible without change of temperature and electric changes, organic life without mechanical, molecular, chemical, thermal, electric, etc., changes. But the presence of these subsidiary forms does not exhaust the essence of the main form in each case. One day we shall certainly “reduce” thought experimentally to molecular and chemical motions in the brain; but does that exhaust the essence of thought?

* * *

Dialectics of natural science[201]: Subject-matter – matter in motion. The different forms and varieties of matter itself can likewise only be known through motion, only in this are the properties of bodies exhibited; of a body that does not move there is nothing to be said. Hence the nature of bodies in motion results from the forms of motion.

1. The first, simplest form of motion is the mechanical form, pure change of place:

(a) Motion of a single body does not exist – [it can be spoken of] only in a relative sense – falling.

(b) The motion of separated bodies: trajectory, astronomy – apparent equilibrium – the end always contact.

(c) The motion of bodies in contact in relation to one another – pressure. Statics. Hydrostatics and gases. The lever and other forms of mechanics proper – which all in their simplest form of contact amount to friction or impact, which are different only in degree. But friction and impact, in fact contact, have also other consequences never pointed out here by natural scientists: they produce, according to circumstances, sound, heat, light, electricity, magnetism.

2. These different forces (with the exception of sound) – physics of heavenly bodies –

(a) pass into one another and mutually replace one another, and

(b) on a certain quantitative development of each force, different for each body, applied to the bodies, whether they are chemically compound or several chemically simple bodies, chemical changes take place, and we enter the realm of chemistry. Chemistry of heavenly bodies. Crystallography – part of chemistry.

3. Physics had to leave out of consideration the living organic body, or could do so; chemistry finds only in the investigation of organic compounds the real key to the true nature of the most important bodies, and, on the other hand, it synthesises bodies which only occur in organic nature. Here chemistry leads to organic life, and it has gone far enough to assure us that it alone will explain to us the dialectical transition to the organism.

4. The real transition, however, is in history – of the solar system, the earth; the real pre-condition for organic nature.

5. Organic nature.

* * *

Classification of the sciences, each of which analyses a single form of motion, or a series of forms of motion that belong together and pass into one another, is therefore the classification, the arrangement, of these forms of motion themselves according to their inherent sequence, and herein lies its importance.

At the end of the last (18th) century, after the French materialists, who were predominantly mechanical, the need became evident for an encyclopedic summing up of the entire natural science of the old Newton-Linnaeus school, and two men of the greatest genius undertook this, Saint-Simon (uncompleted) and Hegel. Today, when the new outlook on nature is complete in its basic features, the same need makes itself felt, and attempts are being made in this direction. But since the general evolutionary connection in nature has now been demonstrated, an external side by side arrangement is as inadequate as Hegel’s artificially constructed dialectical transitions. The transitions must make themselves, they must be natural. Just as one form of motion develops out of another, so their reflections, the various sciences, must arise necessarily out of one another.

* * *

How little Comte can have been the author of his encyclopaedic arrangement of the natural sciences,[202] which he copied from Saint-Simon, is already evident from the fact that it only serves him for the purpose of arranging the means of instruction and course of instruction, and so leads to the crazy enseignement intégral, where one science is always exhausted before another is even broached, where a basically correct idea is pushed to a mathematical absurdity.

Hegel’s division (the original one) into mechanics, chemics, and organics,[203] fully adequate for the time. Mechanics: the movement of masses. Chemics: molecular (for physics is also included in this and, indeed, both – physics as well as chemistry – belong to the same order) motion and atomic motion. Organics: the motion of bodies in which the two are inseparable. For the organism is certainly the higher unity which within itself unites mechanics, physics, and chemistry into a whole where the trinity can no longer be separated. In the organism, mechanical motion is effected directly by physical and chemical change, in the form of nutrition, respiration, secretion, etc., just as much as pure muscular movement.

Each group in turn is twofold. Mechanics: (1) celestial, (2) terrestrial.

Molecular motion: (1) physics, (2) chemistry.

Organics: (1) plant, (2) animal.

* * *

Physiography. After the transition from chemistry to life has been made, then in the first place it is necessary to analyse the conditions in which life has been produced and continues to exist, i.e., first of all geology, meteorology, and the rest. Then the various forms of life themselves, which indeed without this are incomprehensible.

On the “Mechanical” Conception of Nature[204]
Re page 46: The Various Forms of Motion and the Sciences Dealing with Them

Since the above article appeared (Vorwärts, Feb. 9, 1877), Kekulé (Die wissenschaftlichen Ziele und Leistungen der Chemie) has defined mechanics, physics, and chemistry in a quite similar way:

“If this idea of the nature of matter is made the basis, one could define chemistry as the science of atoms and physics as the science of molecules, and then it would be natural to separate that part of modern physics which deals with masses as a special science, reserving for it the name of mechanics. Thus mechanics appears as the basic science of physics and chemistry, in so far as in certain aspects and especially in certain calculations both of these have to treat their molecules or atoms as masses.” [205]

It will be seen that this formulation differs from that in the text and in the previous note only by being rather less definite. But when an English journal (Nature) put the above statement of Kekulé in the form that mechanics is the statics and dynamics of masses, physics the statics and dynamics of molecules, and chemistry the statics and dynamics of atoms,[206] then it seems to me that this unconditional reduction of even chemical processes to merely mechanical ones unduly restricts the field, at least of chemistry. And yet it is so much the fashion that, for instance, Haeckel continually uses “mechanical” and “monistic” as having the same meaning, and in his opinion

“modern physiology ... in its field allows only of the operation of physico-chemical – or in the wider sense, mechanical – forces.” (Perigenesis.) [207]

If I term physics the mechanics of molecules, chemistry the physics of atoms, and furthermore biology the chemistry of proteins, I wish thereby to express the passing of each of these sciences into another, hence both the connection, the continuity, and the distinction, the discrete separation, between the two of them. To go further and to define chemistry as likewise a kind of mechanics seems to me inadmissible. Mechanics – in the wider or narrower sense knows only quantities, it calculates with velocities and masses, and at most with volumes. Where the quality of bodies comes across its path, as in hydrostatics and aerostatics, it cannot achieve anything without going into molecular states and molecular motions, it is itself only an auxiliary science, the prerequisite for physics. In physics, however, and still more in chemistry, not only does continual qualitative change take place in consequence of quantitative change, the transformation of quantity into quality, but there are also many qualitative changes to be taken into account whose dependence on quantitative change is by no means proven. That the present tendency of science goes in this direction can be readily granted, but does not prove that this direction is the exclusively correct one, that the pursuit of this tendency will exhaust the whole of physics and chemistry. All motion includes mechanical motion, change of place of the largest or smallest portions of matter, and the first task of science, but only the first, is to obtain knowledge of this motion. But this mechanical motion does not exhaust motion as a whole. Motion is not merely change of place, in fields higher than mechanics it is also change of quality. The discovery that heat is a molecular motion was epoch-making. But if I have nothing more to say of heat than that it is a certain displacement of molecules, I should best be silent. Chemistry seems to be well on the way to explaining a number of chemical and physical properties of elements from the ratio of the atomic volumes to the atomic weights. But no chemist would assert that all the properties of an element are exhaustively expressed by its position in the Lothar Meyer curve,[208] that it will ever be possible by this alone to explain, for instance, the peculiar constitution of carbon that makes it the essential bearer of organic life, or the necessity for phosphorus in the brain. Yet the “mechanical” conception amounts to nothing else. It explains all change from change of place, all qualitative differences from quantitative ones, and overlooks that the relation of quality and quantity is reciprocal, that quality can become transformed into quantity just as much as quantity into quality, that, in fact, reciprocal action takes place. If all differences and changes of quality are to be reduced to quantitative differences and changes, to mechanical displacement, then we inevitably arrive at the proposition that all matter consists of identical smallest particles, and that all qualitative differences of the chemical elements of matter are caused by quantitative differences in number and by the spatial grouping of those smallest particles to form atoms. But we have not got so far yet.

It is our modern natural scientists’ lack of acquaintance with any other philosophy than the most mediocre vulgar philosophy, like that now rampant in the German universities, which allows them to use expressions like “mechanical” in this way, without taking into account, or even suspecting, the consequences with which they thereby necessarily burden themselves. The theory of the absolute qualitative identity of matter has its supporters – empirically it is equally impossible to refute it or to prove it. But if one asks these people who want to explain everything “mechanically” whether they are conscious of this consequence and accept the identity of matter, what a variety of answers will be heard!

The most comical part about it is that to make “materialist” equivalent to “mechanical” derives from Hegel, who wanted to throw contempt on materialism by the addition “mechanical.” Now the materialism criticised by Hegel – the French materialism of the eighteenth century was in fact exclusively mechanical, and indeed for the very natural reason that at that time physics, chemistry, and biology were still in their infancy, and were very far from being able to offer the basis for a general outlook on nature. Similarly Haeckel takes from Hegel the translation: causae efficientes = “mechanically acting causes,” and causae finales = “purposively acting causes”; where Hegel, therefore, puts “mechanical” as equivalent to blindly acting, unconsciously acting, and not as equivalent to mechanical in Haeckel’s sense of the word. But this whole antithesis is for Hegel himself so much a superseded standpoint that he does not even mention it in either of his two expositions of causality in his Logic – but only in his History of Philosophy, in the place where it comes historically (hence a sheer misunderstanding on Haeckel’s part due to superficiality!) and quite incidentally in dealing with teleology (Logik, III, ii, 3) where he mentions it as the form in which the old metaphysics conceived the antithesis of mechanism and teleology, but otherwise treating it as a long superseded standpoint. Hence Haeckel copied incorrectly in his joy at finding a confirmation of his “mechanical” conception and so arrived at the beautiful result that if a particular change is produced in an animal or plant by natural selection it has been effected by a causa efficiens, but if the same change arises by artificial selection then it has been effected by a causa finalis! The breeder a causa finalis! Of course a dialectician of Hegel’s calibre could not be caught in the vicious circle of the narrow antithesis of causa efficiens and causa finalis. And for the modern standpoint the whole hopeless rubbish about this antithesis is put an end to because we know from experience and from theory that both matter and its mode of existence, motion, are uncreatable and are, therefore, their own final cause; while to give the name effective causes to the individual causes which momentarily and locally become isolated in the mutual interaction of the motion of the universe, or which are isolated by our reflecting mind, adds absolutely no new determination but only a confusing element. A cause that is not effective is no cause.

N. B. Matter as such is a pure creation of thought and an abstraction. We leave out of account the qualitativative differences of things in lumping them together as corporeally existing things under the concept matter. Hence matter as such, as distinct from definite existing pieces of matter, is not anything sensuously existing. When natural science directs its efforts to seeking out uniform matter as such, to reducing qualitative differences to merely quantitative differences in combining identical smallest particles, it is doing the same thing as demanding to see fruit as such instead of cherries, pears, apples, or the mammal as such[209] instead of cats, dogs, sheep, etc., gas as such, metal, stone, chemical compound as such, motion as such. The Darwinian theory demands such a primordial mammal, Haeckel’s pro-mammal,[210] but, at the same time, it has to admit that if this pro-mammal contained within itself in germ all future and existing mammals, it was in reality lower in rank than all existing mammals and primitively crude, hence more transitory than any of them. As Hegel has already shown (Enzyklopädie, I, S. 199), this view, this “one-sided mathematical view,” according to which matter must be looked upon as having only quantitative determination, but, qualitatively, as identical originally, is “no other standpoint than that” of the French materialism of the eighteenth century.[211] It is even a retreat to Pythagoras, who regarded number, quantitative determination as the essence of things.

* * *

In the first place, Kekulé.[212] Then: the systematising of natural science, which is now becoming more and more necessary, cannot be found in any other way than in the inter-connections of phenomena themselves. Thus the mechanical motion of small masses on any heavenly body ends in the contact of two bodies, which has two forms, differing only in degree, viz., friction and impact. So we investigate first of all the mechanical effect of friction and impact. But we find that the effect is not thereby exhausted: friction produces heat, light, and electricity, impact produces heat and light if not electricity also – hence conversion of motion of masses into molecular motion. We enter the realm of molecular motion, physics, and investigate further. But here too we find that molecular motion does not represent the conclusion of the investigation. Electricity passes into and arises from chemical transformation. Heat and light, ditto. Molecular motion becomes transformed into motion of atoms – chemistry. The investigation of chemical processes is confronted by the organic world as a field for research, that is to say, a world in which chemical processes take place, although under different conditions, according to the same laws as in the inorganic world, for the explanation of which chemistry suffices. In the organic world, on the other hand, all chemical investigations lead back in the last resort to a body – protein – which, while being the result of ordinary chemical processes, is distinguished from all others by being a self-acting, permanent chemical process. If chemistry succeeds in preparing this protein, in the specific form in which if obviously arose, that of a so-called protoplasm, a specificity, or rather absence of specificity, such that it contains potentially within itself all other forms of protein (though it is not necessary to assume that there is only one kind of protoplasm), then the dialectical transition will have been proved in reality, hence completely proved. Until then, it remains a matter of thought, alias of hypothesis. When chemistry produces protein, the chemical process will reach out beyond itself, as in the case of the mechanical process above, that is, it will come into a more comprehensive realm, that of the organism. Physiology is, of course, the physics and especially the chemistry of the living body, but with that it. ceases to be specially chemistry: on the one hand its domain becomes restricted but, on the other hand, inside this domain it becomes raised to a higher power.


193. Hegel, Encyclopaedia of the Philosophical Sciences, § 128, Addendum.

194. Op. cit., §98, Addendum 1: “...attraction, is as essential a part of matter as repulsion.”

195. See Hegel, Science of Logic, Book 1, Section 11, Chapter 1, Observation on Kant’s antinomy of the indivisibility and infinite divisibility of time, space and matter.

196. Hegel, Naturphilosophie (Philosophy of Nature), § 261, Addendum.

197. The idea of the preservation of the quantity of motion was expressed by Descartes in his Le Traite de la Lumiere (Treatise on Light), first part of the work Le Monde (The World), written in 1630-33 and published posthumously in 1664, and in his letter to Debeaune dated April 30, 1639. This proposition is given in its most complete form in R. Des-Cartes, Principia Philosophiae (Principles of Philosophy), Amstelodami, 1644, Pars secunda, XXXVI.

198. Grove, The Correlation of Physical Forces (see Note 16). On pp. 20-29 Grove speaks of the “indestructibility of force” when mechanical motion is converted into a “state of tension” and into heat.

199. This note was written on the same sheet as “Outline of Part of the Plan” and is a conspectus of ideas developed by Engels in the chapter “Basic Forms of Motion” (see this edition, pp. 19 and 69-86).

200. Grove, The Correlation of Physical Forces (see Note 16). By “affections of matter” Grove means “heat, light, electricity, magnetism, chemical affinity, and motion” (p. 15) and by “motion” he means mechanical motion or displacement.

201. This outline was written on the first sheet of the first folder of Dialectics of Nature. As regards its contents, it coincides with Engels’s letter to Marx dated May 30. 1873. This letter begins with the words: “This morning in bed the following dialectical ideas about natural science came into my head.” The exposition of these ideas is more definite in the letter than in the present outline. It may be inferred that the outline was written before the letter, on the same day, May 30, 1873. Not counting the fragment on Buchner (see this edition, pp. 202-07), which was written shortly before this outline, all the other chapters and fragments of Dialectics of Nature were written later, i.e., after May 30, 1873.

202. A. Comte set out this system of classification of the sciences in his main work A Course of Positive Philosophy, first published in Paris in 1830-42. The question of classification of the sciences is specially dealt with in the second lecture, in Volume I of the book, headed “An Exposition of the Plan of This Course, or General Considerations Concerning the Hierarchy of the Positive Sciences.” See A. Comte, Cours de philosophic positive, t. I, Paris 1830.

203. Engels is referring to the third part of Hegel’s Science of Logic, first published in 1816. In his Philosophy of Nature, Hegel denotes these three main divisions of natural science by the terms “mechanics,” “physics” and “organics.”

204. This note is one of those three larger notes (Noten) which Engels put in the second folder of materials for Dialectics of Nature (the smaller notes were put in the first and fourth folders). Two of these notes – “On the Prototypes of the Mathematical Infinite in the Real World” and “On the ‘Mechanical’ Conception of Nature” are Notes or Addenda to [Anti]-Dühring, in which Engels elaborates some very important ideas that were only outlined, or stated in brief, in various parts of [Anti]-Dühring. The third note, “Nageli’s Inability to Cognise the Infinite,” has nothing to do with [Anti]-Dühring. The first two notes were in all probability written in 1885. In any case, they cannot date from earlier than mid-April 1884, when Engels decided to prepare for the press a second, enlarged edition of (Anti)- Dühring, or later than late September 1885, when Engels finished and sent to the publisher his Preface to the second edition of the book. Engels’s letters to Bernstein and Kautsky in 1884 and to Schluter in 1885 indicate that he planned to write a series of Addenda and Appendices of a natural-scientific character to various passages in [Anti]-Dühring, with a view to giving them at the end of the second edition of the book. But owing to being extremely busy with other matters (above all with his work on the second and third volumes of Marx’s Capital); Engels was prevented from carrying out his intention. He only managed to make a rough outline of two “notes” or “addenda,” to pp. 17-18 and p. 46 of the text of the first edition of [Anti] -Dühring. The present notice is the second of these “notes.”

The heading “On the ‘Mechanical’ Conception of Nature” was given by Engels in his list of contents of the second folder of Dialectics of Nature. The sub-heading “Note 2 to p. 46”: “the various forms of motion and the sciences dealing with them” occurs at the beginning of this notice.

205. A. Kekulé, Die wissenschaftlichen Ziele und Leistungen der Chemie, Bonn, 1878, S. 12.

206. This refers to an item in Nature No. 420, November 15, 1877, summarising A. Kekulé’s speech on October 18, 1877, when he took the office of rector at the University of Bonn. In 1878 the speech was published in pamphlet form, under the title The Scientific Aims and Achievements of Chemistry.

207. E. Haeckel, Die Perigenesis der Plastidule oder die Wellenzeugung der Lebensteuchen. Ein Versuche zur mechanischen Erkldrung der elementaren Entwickelungs-Vorgange, Berlin, 1876, S. 13.

208. The Lothar Meyer curve shows the relation between the atomic weights of the elements and their atomic volumes. It was constructed by L. Meyer who dealt with it in his article “Die Natur der chemischen Elemente als Funktion ihrer Atomgewichte,” which appeared in 1870 in the journal Annalen der Chemie und Pharmacie. The discovery of the correlation between the atomic weights of the elements and their physical and chemical properties was made by the great Russian scientist D. I. Mendeleyev, who was the first to formulate the periodic law of the chemical elements in his article “The Correlation of the Properties of the Elements and Their Atomic Weights,” published in March 1869, i.e., a year prior to L. Meyer’s article, in the Journal of Russian Chemical Society. Meyer, too, was close to establishing the periodic law when he learned about Mendeleyev’s discovery. The curve made by him graphically illustrated the law discovered by Mendeleyev, except that it expressed the law in external and, unlike Mendeleyev, one sided terms. Mendeleyev went much farther than Meyer in his conclusions. On the basis of the periodic law discovered by him, Mendeleyev predicted the existence and specific properties of chemical elements still unknown at that time; whereas L. Meyer in his subsequent works revealed a lack of understanding of the nature of the periodic law.

209. See Note 183.

210. E. Haeckel, Naturliche Schopfungsgeschichte, 4. Aufl., Berlin, 1873, S. 538, 543, 588; Anthropogenie, Leipzig, 1874, S. 460, 465, 492.

211. Hegel, Encyclopaedia of the Philosophical Sciences, § 99, Addendum.

212. This fragment was written on a separate sheet marked Noten (Notes). It may be an original outline of the Second Note to [Anti]-Dühring headed “On the ‘Mechanical’ Conception of Nature.”