The apprehension of this principle--a principle common to all the ontological systems of antiquity--is the first step in the enquiry, as to what are the original substances out of which all creation comes into being and is maintained. The proof of this principle is the manifest order and causation recognisable in the world. If things could arise out of nothing, all existence would be confused and capricious. The regularity of Nature subsists--
Materies quia rebus reddita certast Gignundis e qua constat quid possit oriri.
The complement of this first principle is the proposition that nothing is annihilated, but all existences are resolved into their ultimate elements. As the first is a necessary inference from the existence of universal order, the second is proved by the perpetuity of creation and the observed transformation of things into one another.
The original substances out of which all things are produced, and into which they are ultimately resolved, are found to be certain primordial particles of matter or atoms, which are called by various names--"materies," "genitalia corpora," "semina rerum," "corpora prima." Some of these names, it may be observed, are expressive not only of their primordial character, but also of a germinative or productive power. The objection that these atoms are invisible to our senses is met by showing that there are many invisible forces acting in Nature, the effects of which prove that they must be bodies,--
Corporibus caecis igitur natura gerit res.
In addition to bodily substance there must also be vacuum or s.p.a.ce; otherwise there could be no motion in the universe, and without motion nothing could come into being. The existence of matter is proved by our senses, of vacuum by the necessity of there being s.p.a.ce for matter to move in, and also by the varying density of bodies. But besides body and vacuum there is no other absolute substance--
Ergo praeter inane et corpora tertia per se Nulla potest rerum in numero natura relinqui[4].
All material bodies are either elemental substances or compounded out of a union of these substances. The elemental substances are indestructible and indivisible. This is proved by the necessities of thought (i. 498, etc.) and of Nature. If there were no ultimate limit to the divisibility of these substances, if there were not something immutable underlying all phenomena, there could be no law or order in the world. The existence and ultimate const.i.tution of the atoms is thus enunciated--
Sunt igitur solida primordia simplicitate Quae minimis stipata cohaerent partibus arte, Non ex illarum conventu conciliata, Sed magis aeterna pollentia simplicitate, Unde neque avelli quicquam neque deminui iam Concedit natura reservans semina rebus[5].
At this stage in the argument, from line 635 to 920 of Book I, the first principles of other philosophies, and particularly of the systems of Herac.l.i.tus, Empedocles, and Anaxagoras, are discussed at considerable length, and shown to be inconsistent with the actual appearance of things and with the principles already established.
The argument starts anew at line 920, and it is shown that the atoms must be infinite in number, and s.p.a.ce infinite in extent;--the contrary supposition being both inconceivable and incompatible with the origin, preservation, and renewal of all existing things. It is shown also that the existing order of things has not come into being through design, but by infinite experiments through infinite time.
The doctrine that all things tend to a centre is denied, and the book concludes with the imaginative presentation of the thought that, if matter were not infinite, the whole visible fabric of the world would perish in a moment, "and leave not a rack behind."
The second book opens with an impressive pa.s.sage, in which the security and charm of the contemplative life is contrasted with the restless anxieties and alarms of the life of worldly ambition. The argument then proceeds to explain the process by which these atoms, primordial, indestructible, and infinite in number, combine together in infinite s.p.a.ce, so as to carry on the birth, growth, and decay of all things. While the sum of things always remains the same, there is constant change in all phenomena. This is explicable only on the supposition of the original elements being in eternal motion. The atoms are borne through s.p.a.ce, either by their own weight, or by contact with one another, with a rapidity of motion far beyond that of any visible bodies. All motion is naturally in a downward direction and in parallel lines, but to account for the contact of the atoms with one another it must be supposed that in their movements they make a slight declension from the straight line at uncertain intervals.
This liability to declension is the sole thing to break the chain of necessity--"quod fati foedera rumpat." It is through this liability in the primal elements that volition in living beings becomes possible.
As the sum of matter in the universe is constant, so the motions of the atoms always have been and always will be the same[6]. All things are in ceaseless motion, although they may present to our senses the appearance of perfect rest.
It is necessary further to a.s.sume the existence of other properties in the atoms, in order to account for the variety in Nature, and the individuality of existing things. They have original differences in form; some are smooth, others round, others rough, others hooked, &c.
These varieties in form are not infinite, but limited in number.
As the diversity in the world depends on the diversity of these forms, the order and regularity of Nature imply that there is a limit to these varieties. But while they are limited, the individuals of each kind are infinite, otherwise the primordial atoms would be finite in number, and there could be no cohesion among atoms of the same kind, in the vast and chaotic sea of matter--
Unde ubi qua vi et quo pacto congressa coibunt Materiae tanto in pelago turbaque aliena[7]?
The motions which tend to the support and the destruction of created things are balanced by one another: there must be an equilibrium in these opposing forces--
Sic aequo geritur certamine principiorum Ex infinito contractum tempore bellum[8].
Death and birth succeed one another, as now the vitalising, now the destructive forces gain the upper hand.
Further, the great diversity in Nature is to be accounted for by diversity, not only in the original forms of matter, but also in their modes of combination. No existing thing is composed solely of one kind of atoms. The greater the variety of forces and powers which anything displays, the greater is the variety of the elements out of which it was originally composed. Of all visible objects the earth contains the greatest number of elements; therefore it has justly obtained the name of the universal mother. There is however a limit to the modes in which atoms can combine with one another: each nature appropriates elements suitable to its being and rejects those unsuitable. All existing things differ from one another in consequence of the difference in their elements and in their modes of combination. The different modes of combination give rise to many of the secondary properties of matter, which are not in the original elements. Colour, for instance, is not one of the original properties of atoms: for all colour is changeable, and all change implies the death of what previously existed. Moreover, colour depends on light, and the atoms never come forth into the light. The atoms are also devoid of heat and cold, of sound, taste, and smell. All these properties must be kept distinct from the original elements--
Immortalia si volumus subiungere rebus Fundamenta quibus nitatur summa salutis; Ne tibi res redeant ad nilum funditus omnes[9].
Further, although they are the origin of all living and sentient things, the atoms themselves are devoid of sense and life, otherwise they would be liable to death. All living things are merely results of the constant changes in the primordial elements contained in the heavens and the earth. Hence the heaven is addressed as the father, the earth as the mother, of all things that have life.
Finally, from the infinity of s.p.a.ce and matter, it may be inferred that there are infinite other worlds and systems beside our own. Many elements were added from the infinite universe to our system before it reached maturity: and many indications prove that the period of growth is now past, and that we are living in the old age of the world.
The sum of the first two books, in which the principles of the atomic philosophy are methodically unfolded and ill.u.s.trated, is, accordingly, to this effect:--that all things have their origin in, and are sustained by, the various combinations and motions of solid elemental atoms, infinite in number, various in form, but not infinite in the variety of their forms,--not perceptible to our senses, and themselves devoid of sense, of colour, and of all the secondary properties of matter. These atoms, by virtue of their ultimate conditions, are capable only of certain combinations with one another. These combinations have been brought about by perpetual motion, through infinite s.p.a.ce and through all eternity. As the order of things now existing has come into being, so it must one day perish. Only the atoms will permanently remain, moving unceasingly through s.p.a.ce, and forming new combinations with one another.
These first principles being established, the way is made clear for the true explanation, according to natural laws, of those phenomena which give rise to and maintain the terrors of superst.i.tion.
The third book treats of the nature of the mind, and of the vital principle. As it is by the fear of death, and of eternal torment after death, that human life is most disturbed, it is necessary to explain the nature of the soul, and to show that it perishes in death along with the body.
The mind and the vital principle are parts of the man as much as the hands, feet, or any other members. The mind is the directing principle, seated in the centre of the breast. The vital principle is diffused over the whole body, obedient to and in close sympathy with the mind. The power which the mind has in moving the body proves its own corporeal nature, as motion cannot take place without touch, nor touch without the presence of a bodily substance.
The soul (including both the mind and vital principle) is, therefore, material, formed of the finest or minutest atoms, as is proved by the extreme rapidity of its movement, and by the fact that there is nothing lost in appearance or weight immediately after death:--
Quod simul atque hominem leti secura quies est Indepta atque animi natura animaeque recessit, Nil ibi libatum de toto corpore cernas Ad speciem, nil ad pondus: mors omnia praestat Vitalem praeter sensum calidumque vaporem[10].
Four distinct elements enter into the composition of the soul--heat, wind, calm air, and a finer essence "quasi anima animai." The variety of disposition in men and animals depends on the proportion in which these elements are mixed.
The soul is the guardian of the body, inseparably united with it, as the odour is with frankincense; nor can the soul be disconnected from the body without its own destruction. This intimate union of soul and body is proved by many facts. They are born, they grow, and they decay together. The mind is liable to disease, like the body. Its affections are often dependent on bodily conditions. The difficulties of imagining the state of the soul as existing independently of the body are next urged; and the book concludes with a long pa.s.sage of sustained elevation of feeling, in which the folly and the weakness of fearing death are pa.s.sionately insisted upon.
The fourth book, which treats of the images which all objects cast off from themselves, and, in connexion with that subject, of the senses generally, and of the pa.s.sion of love, is intimately connected with the preceding book. If there is no life after death, what is the origin of the universal belief in the existence of the souls of the departed? Images cast off from the surface of bodies, and borne incessantly through s.p.a.ce without force or feeling, appearing to the living sometimes in sleep and sometimes in waking visions, have suggested the belief in the ghosts of the dead, and in many of the portents of ancient mythology. The rapid formation and motion of these images and their great number are explained by various a.n.a.logies. Some apparent deceptions of the senses are next mentioned and explained.
These deceptions are shown to be not in the senses, but in our minds not rightly interpreting their intimations. There is no error in the action of the senses. They are our "prima fides"--the foundation of all knowledge and of all conduct--
Non modo enim ratio ruat omnis, vita quoque ipsa Concidat extemplo, nisi credere sensibus ausis[11].
Images that are too fine to act on the senses sometimes directly affect the soul itself. Discordant images unite together in the air, and present the appearance of Centaurs, Scyllas, and the like. In sleep, images of the dead--
Morte obita quorum tellus amplect.i.tur ossa[12],--
appear, and give rise to the belief in the existence of ghosts.
The mind sees in dreams the objects in which it is most interested, because, although all kinds of images are present, it can discern only those of which it is expectant.
Several other questions are discussed in connexion with the doctrine of the "simulacra." The final cause of the senses and the appet.i.tes is denied, and, by implication, the argument from design founded on the belief in final causes. The use of everything is discovered through experience. We do not receive the sense of sight in order that we may see, but having got the sense of sight, we use it--
Nil ideo quoniam natumst in corpore ut uti Possemus, sed quod natumst id procreat usum[13].
There follows an account of sleep, and of the condition of the mind during that state; and the book concludes with a physical account of the pa.s.sion of love, which is dependent on the action of the simulacra on the mind. Love is shown also to arise from natural causes, and not to be engendered by divine influence. The fatal consequences of yielding to the pa.s.sion are then enforced with much poetical and satiric power.
The object of the fifth book is to explain the formation of our system--of earth, sea, sky, sun, and moon,--the origin of life upon the earth, and the advance of human nature from a savage state to the arts and usages of civilisation. The purpose of these discussions is to show that all our system was produced and is maintained by natural agency, that it is neither itself divine nor created by divine power, and that, as it has come into existence, so it must one day perish.
As the parts of our system,--earth, water, air, and heat,--are perishable, and constantly pa.s.sing through processes of decay and renovation, the system must have had a beginning, and will have an end. There must at last be an end of the long war between the contending elements.
The world came into existence as the result not of design, but of every variety of combination in the elemental atoms throughout infinite time. Originally all were confused together. Gradually those that had mutual affinities combined and separated themselves from the rest. The earthy particles sank to the centre. The elemental particles of the empyrean (aether ignifer) formed the "moenia mundi." The sun and moon were formed out of the particles that were neither heavy enough to combine with the earth, nor light enough to ascend to the highest heaven. Finally, the liquid particles separated from the earth and formed the sea. Highest above all is the empyrean, entirely separated from the storms of the lower air, and moving round with its stars by its own impetus. The earth is at rest in the centre of our system, supported by the air, as our body is by the vital principle.
The movements of the stars and of the sun and moon through the heavens are next explained; then the origin of vegetable and animal life on the earth, and the beginning and progress of human society.
First plants and trees, afterwards men and animals, were produced from the earth in the early and vigorous prime of the world. Many of the animals originally produced afterwards became extinct. Those only were capable of continuation which had either some faculty of self-preservation against others, or were useful to man, and so shared his protection. The existence of monsters such as Scylla, the Centaurs, the Chimaera, is shown to be impossible according to the natural laws of production.
The earliest condition of man was one of savage vigour and power of endurance, but liable to danger and destruction from many causes.
The first humanising influence is traced to domestic union and the affection inspired by children--
Et Venus inminuit viris puerique parentum Blanditiis facile ingenium fregere superb.u.m[14].
The origin of language is next explained, then that of civil society, of religion, and of the arts,--the general conclusion being that all progress is the result of natural experience, not of divine guidance.