Polarity is an all-pervasive feature in nature. It does not only exist as the North and South Poles of the earth. Polarity is to be found in the sun and moon and other planets. It also exists at the subatomic level, where nuclei behave precisely as if they possess not one but two pairs of magnetic poles. Engels described it thus:

Dialectics, has proved from the result of our experience of nature so far that all polar opposites in general are determined by the mutual action of the two opposite poles on each other, that the separation and opposition of these poles exist only within their mutual connection and union, and, conversely, that their union exists only in their separation and their mutual connection only in their opposition. This once established, there can be no question of a final cancelling out of repulsion and attraction, or of a final partition between the one form of motion in one half of matter and the other form in the other half, consequently there can be no question of mutual penetration or of absolute separation of the two poles. It would be equivalent to demanding in the first case that the north and south poles of a magnet should mutually cancel themselves out or, in the second case, that dividing a magnet in the middle between the two poles should produce on one side a north half without a south pole, and on the other side a south half without a north pole.[37]

There are some things which people consider to be absolute and immutable opposites. For instance, when we wish to convey the notion of extreme incompatibility, we use the term “polar opposites” – north and south are taken to be absolutely fixed and opposed phenomena. For over a thousand years, sailors have placed their faith in the compass, which guided them through unknown oceans, always pointing to this mysterious thing called the North Pole. Yet closer analysis shows that the North Pole is neither fixed nor stable. The earth is surrounded by a strong magnetic field (a geocentric axis dipole), as if a gigantic magnet were present at the centre of the earth, aligned parallel to the earth’s axis. This is related to the metallic composition of the earth’s core, which is mainly made up of iron. In the 4.6 billion years since the solar system was formed, the rocks on earth have formed and reformed many times. And not only the rocks but everything else. Detailed measurements and investigation has now proved beyond doubt that the location of the magnetic poles is continually shifting. At the present time, they are moving very slowly – 0.3 degrees every million years. This phenomenon is a reflection of complex changes taking place in the earth, the atmosphere and the sun’s magnetic field.

So small is the shift that for centuries it remained undetected. However, even this apparently imperceptible process of change gives rise to a sudden and spectacular leap, in which north becomes south and south becomes north. The changes in the location of the poles are accompanied by fluctuations in the strength of the magnetic field itself. This gradual process, characterised by a weakening of the magnetic field, culminates in a sudden leap. They change place, literally turning into their opposite. After this, the field starts to recover and gather strength again.

This revolutionary change has occurred many times during the history of the earth. It has been estimated that more than 200 such polar reverses have taken place in the last 65 million years; at least four have occurred in the last four million years. About 700,000 years ago, the north magnetic pole was located somewhere in Antarctica, the present south geographical pole. At this moment, we are in a process of weakening of the earth’s magnetic field, which will inevitably culminate in a new reversal. The study of the earth’s magnetic history is the special field of an entirely new branch of science – palaeomagnetism – which is attempting to construct maps of all the reversals of the poles throughout the history of our planet. The discoveries of palaeomagnetism, in turn, have provided conclusive evidence for the correctness of the theory of continental drift. When rocks (especially volcanic rocks) create iron-rich minerals, these respond to the earth’s magnetic field, as it exists at that moment, in the same way that pieces of iron react to a magnet, their atoms orienting in line with the field axis. In effect, they behave like a compass. By comparing the orientations of minerals in rocks of the same age in different continents, it is possible to trace the movements of the continents, including those which no longer exist, or only exist as tiny remnants.

In the reversal of the poles we see a most graphic example of the dialectical law of the unity and interpenetration of opposites. North and south – polar opposites in the most literal sense of these words – are not only inseparably united but determine each other by means of a complex and dynamic process, which culminates in a sudden leap in which supposedly fixed and immutable phenomena change into their opposites. And this dialectical process is not the arbitrary and fanciful invention of Hegel or Engels, but is conclusively demonstrated by the most recent discoveries of palaeomagnetism. Truly it has been said, “when men are silent, the stones cry out!”

Attraction and repulsion is an extension of the law of the unity and interpenetration of opposites. It is a law that permeates the whole of nature, from the smallest phenomena to the largest. At the base of the atom are immense forces of attraction and repulsion. The hydrogen atom, for example, is made up of a proton and an electron held together by electrical attraction. The charge carried by a particle may be positive or negative. Similar charges repel each other, whereas opposite kinds attract. Thus, within the nucleus, protons repel each other, but the nucleus is held together by tremendous nuclear force. In very heavy nuclei, however, the force of electrical repulsion can reach a point where the nuclear force is overcome and the nucleus flies apart.

Engels points out the universal role of attraction and repulsion:

All motion consists in the interplay of attraction and repulsion. Motion, however, is only possible when each individual attraction is compensated by a corresponding repulsion somewhere else. Otherwise in time one side would get the preponderance over the other and then motion would finally cease. Hence all attractions and all repulsions in the universe must mutually balance one another. Thus the law of the indestructibility and uncreatability of motion is expressed in the form that each movement of attraction in the universe must have as its complement an equivalent movement of repulsion and vice versa; or, as ancient philosophy – long before the natural-scientific formulation of the law of conservation of force or energy – expressed it: the sum of all attractions in the universe is equal to the sum of all repulsions.

In Engels’ day, the prevailing idea of motion was derived from classical mechanics, where motion is imparted from an external force that overcomes the force of inertia. Engels was quite scathing about the very expression “force”, which he considered one-sided and insufficient to describe the real processes of nature. Engels wrote:

All natural processes are two-sided, they are based on the relation of at least two operative parts, action and reaction. The notion of force, however, owing to its origin from the action of the human organism on the external world, and further from terrestrial mechanics, implies that only one part is active, operative, the other part being passive, receptive.[38]

Engels was far in advance of his time in being highly critical of this notion, which had already been attacked by Hegel. In his History of Philosophy, Hegel remarks that “It is better (to say) that a magnet has a soul (as Thales expresses it) than that it has an attractive force; force is a kind of property that, separate from matter, is put forward as a kind of predicate – while soul, on the other hand, is this movement itself, identical with the nature of matter.” This remark of Hegel, approvingly quoted by Engels, contains a profound idea – that motion and energy are inherent to matter. Matter is self-moving and self-organising.

Even the word “energy” was not, in Engels’ opinion, entirely adequate, although greatly to be preferred to “force”. His objection was that “It still makes it appear as if ‘energy’ was something external to matter, something implanted in it. But in all circumstances it is to be preferred to the expression ‘force’.”[39] The real relation has been demonstrated by Einstein’s theory of the equivalence of mass and energy, which shows that matter and energy are one and the same thing. This was precisely the standpoint of dialectical materialism, as expressed by Engels, and even anticipated by Hegel, as the above quotation shows.

  1. Engels, F. Dialectics of Nature, p. 96.

  2. Ibid pp. 95-6 and p. 110.

  3. Ibid p.108 and p.107.