On the Infinite Universe and Worlds
(DE L'INFINITO UNIVERSO ET MONDI)
Philotheo. [The whole universe] then is one, the heaven, the immensity of embosoming space, the universal envelope, the ethereal region through which the whole hath course and motion. Innumerable celestial bodies, stars, globes, suns and earths may be sensibly perceived therein by us and an infinite number of them may be inferred by our own reason. The universe, immense and infinite, is the complex of this [vast] space and of all the bodies contained therein.
Elpino. So that there are no spheres with concave and convex surfaces nor deferent orbs; but all is one field, one universal envelope.
Philotheo. So it is.
Elpino. The opinion of diverse heavens hath then been caused by diverse motions of the stars and by the appearance of a sky filled with stars revolving around the earth; nor can these luminaries by any means be seen to recede one from another; but, maintaining always the same distance and relation one to another, and a certain course, they [appear to] revolve around the earth, even as a wheel on which are nailed innumerable mirrors revolveth around his own axis. Thus it is considered obvious from the evidence of our eyes that these luminaries have no motion of their own; nor can they wander as birds through the air; but they move only by the revolution of the orbs to which they are fixed, whose motion is effected by the divine pulse of some [supreme] intelligence.
Theophilo. Such is the common opinion. But once the motion is understood of our own mundane star which is fixed to no orb, but impelled by her own intrinsic principle, soul and nature, taketh her course around the sun through the vastness of universal space, and spinneth around her own centre, then this opinion will be dispelled. Then will be opened the gate of understanding of the true principles of nature, and we shall be enabled to advance with great strides along the path of truth which hath been hidden by the veil of sordid and bestial illusions and hath remained secret until to-day, through the injury of time and the vicissitudes of things, ever since there succeeded to the daylight of the ancient sages the murky night of the foolhardy sophists.
Naught standeth still, but all things swift and whirl
Elpino. Indubitable that the whole fantasy of spheres bearing stars and fires, of the axes, the deferents, the functions of the epicycles, and other such chimeras, is based solely on the belief that this world occupieth as she seemeth to do the very centre of the universe, so that she alone being immobile and fixed, the whole universe revolveth around her.
Philotheo. This is precisely what those see who dwell on the moon and on the other stars in this same space, whether they be earths or suns.
Elpino. Suppose then for the moment that the motion of our earth causeth the appearance of daily world motion, and that by her own diverse motions the earth causeth all those motions which seem to appertain to the innumerable stars, we should still say that the moon, which is another earth, moveth by her own force through the air around the sun. Similarly, Venus, Mercury and the others which are all earths, pursue their courses around the same father of life.
Philotheo. It is so.
Elpino. The proper motions of each of these are those of their apparent motions which are not due to our so-called world motion; and the proper motions of the bodies known as fixed stars (though both their apparent fixity and the world motion should be referred to our earth) are more diverse and more numerous than the celestial bodies themselves. For if we could observe the motion of each one of them, we should find that no two stars ever hold the same course at the same speed; it is but their great distance from us which preventeth us from detecting the variations. However much these stars circulate around the solar flame or spin round their own centres in order to participate in the vital heat [of a sun], it is impossible for us to detect their diverse approach toward and retreat from us.
Philotheo. That is so.
Elpino. There are then innumerable suns, and an infinite number of earths revolve around those suns, just as the seven we can observe revolve around this sun which is close to us.
Philotheo. So it is.
Elpino. Why then do we not see the other bright bodies which are earths circling around the bright bodies which are suns? For beyond these we can detect no motion whatever; and why do all other mundane bodies (except those known as comets) appear always in the same order and at the same distance?
Philotheo. The reason is that we discern only the largest suns, immense bodies. But we do not discern the earths because, being much smaller, they are invisible to us. Similarly it is not impossible that other earths revolve around our sun and are invisible to us on account either of greater distance or of smaller size, or because they have but little watery surface, or because such watery surface is not turned toward us and opposed to the sun, whereby it would be made visible as a crystal mirror which receiveth luminous rays; whence we perceive that it is not marvellous or contrary to nature that often we hear that the sun hath been partially eclipsed though the moon hath not been interpolated between him and our sight. There may be innumerable watery luminous bodies -- that is, earths consisting in part of water -- circulating around the sun, besides those visible to us; but the difference in their orbits is indiscernible by us on account of their great distance, wherefore we perceive no difference in the very slow motion discernible of those visible above or beyond Saturn; still less doth there appear any order in the motion of all around the centre, whether we place our earth or our sun as that centre.
Elpino. How then wouldst thou maintain that all of these bodies, however far from their centre, that is from the sun, can nevertheless participate in the vital heat thereof?
Philotheo. Because the further they are from the sun, the larger is the circle of their orbit around it; and the greater their orbit, the more slowly they accomplish their journey round the sun; the more slowly they move, the more they resist the hot flaming rays of the sun.
Elpino. You maintain then that though so distant from the sun, these bodies can derive therefrom all the heat that they need. Because spinning at a greater rate around their own centre and revolving more slowly around the sun, they can derive not only as much heat but more still if it were needed; since by the more rapid spin around her own centre, such part of the convexity of the earth as hath not been sufficiently heated is the more quickly turned to a position to receive heat; while from the slower progress around the fiery central body, she stayeth to receive more firmly the impression therefrom, and thus she will receive fiercer flaming rays.
Philotheo. That is so.
Elpino. Therefore you consider that if the stars beyond Saturn are really motionless as they appear, then they are those innumerable suns or fires more or less visible to us around which travel their own neighbouring earths which are not discernible by us.
Theophilo. Yes, we should have to argue thus, since all earths merit the same amount of heat, and all suns merit the same amount.
Elpino. Then you believe that all those are suns?
Philotheo. Not so, for I do not know whether all or whether the majority are without motion, or whether some circle around others, since none hath observed them. Moreover they are not easy to observe, for it is not easy to detect the motion and progress of a remote object, since at a great distance change of position cannot easily be detected, as happeneth when we would observe ships in a high sea. But however that may be, the universe being infinite, there must ultimately be other suns. For it is impossible that heat and light from one single body should be diffused throughout immensity, as was supposed by Epicurus if we may credit what others relate of him.  Therefore it followeth that there must be innumerable suns, of which many appear to us as small bodies; but that star will appear smaller which is in fact much larger than that which appeareth much greater.
Elpino. All this must be deemed at least possible and expedient.
Philotheo. Around these bodies there may revolve earths both larger and smaller than our own.
Elpino. How shall I know the difference? How, I say, shall I distinguish fiery bodies from earths?
Philotheo. Because fiery bodies are fixed and earths are in motion; because fiery bodies scintillate and earths do not; of which indications, the second is more easily perceptible than the first.
Elpino. They say that the appearance of scintillation is caused by the great distance from us.
Philotheo. If that were so, the sun would not scintillate more than all the others; and the small stars which are more remote would scintillate more than the larger which are nearer to us.
Elpino. Do you believe that fiery worlds are inhabited even as are watery bodies?
Philotheo. Neither more nor less.
Elpino. But what animals could live in fire?
Philotheo. You must not regard these worlds as compounded of identical parts, for then they would be not worlds but empty masses, vain and sterile. Therefore it is convenient and natural to assume that their parts are diverse just as our own and other earths comprise diverse parts, though some celestial bodies have the appearance of illumined water as others of shining flames.
Elpino. You believe then that the prime matter of the sun differeth not in consistency and solidity from that of the earth? (For I know that you do not doubt that a single prime matter is the basis of all things.)
Philotheo. This indeed is certain; it was understood by Timaeus, and confirmed by Plato.  All true philosophers have recognized it, few have explained it, no one in our time hath understood it, so that many have confused understanding in a thousand ways, through corruption of fashion and defect of principles.
Elpino. The Instructed Ignorance of the Cusan seems to have approached, if not reached, this interpretation when, speaking of the conditions of our earth, he saith:
Think not that from her darkness and black colour we can argue that the earthly body is vile and more ignoble than others; for if we inhabited the sun, we should not see it so brilliant as we do from our circumferential position. Moreover even now if we fix our eye well on the sun, we discover that toward his centre he hath almost an earth or certainly as it were a watery and cloudy body which diffuseth bright and shining light as from a circumferential zone, whence we deduce that the sun no less than the earth is composed of his own elements. 
Philotheo. So far the Cusan speaketh divinely. But continue and relate that which followeth.
Elpino. From what followeth might be inferred that this earth is another sun and all the stars similarly suns. The Cusan speaketh thus: If some person were situated beyond the fiery zone of [elemental] fire, our earth would appear to him by means of the fire as a bright star on his horizon;  just as to us, who are within the horizon of the solar region, the sun appeareth very bright, and the moon appeareth not similarly bright, perhaps because in relation to her horizon we have a more median position or, as saith the Cusan, we are nearer the centre, that is, within the moon's humid and watery region; so though she may have her own light, nevertheless it doth not appear to us, and we see only the light reflected from the sun on the moon's watery surface.
Philotheo. This honest Cusan hath known and understood much; he is indeed one of the most remarkably talented men who hath lived in our world. As to the apprehension of truth, however, he is a swimmer in the tempestuous waves cast now upward, now downward, for he did not see the light continuously, openly and clearly, and he swam not in calm and quiet, but with interruptions and at certain intervals; the reason being that he did not discard all those false principles imbibed with the usual doctrine from which he had parted, so that perhaps by dint of industry the title came to fit him well of his own book concerning Instructed Ignorance or on Uninstructed Doctrine.
Elpino. What is the principle which he should have discarded?
Philotheo. That the element of fire is, like air, subject to attrition owing to the motion of the heaven, and that fire is an extremely subtle body; this is contrary to that reality and truth which is manifest to us, as we will consider in dealing with other subjects and in discourses on this very subject, where we conclude that there is necessarily one corporeal principle, solid and consistent, of a hot no less than of a cold body,  and that the ethereal region can be neither fire nor made of fire, but is enflamed and kindled by the neighbouring solid and dense body which is the sun. So that, when we can speak according to nature, there is no need to have recourse to mathematical fantasies. We see that no part of the earth shineth by her own brightness, but that some parts shine by reflection from elsewhere, as for example her watery region and her vaporous atmosphere which receive heat and light from the sun and can transfer both to the surrounding regions. Therefore there must be a primary body which must be of itself both bright and hot and consequently also unchanging, solid and dense; for a rare and tenuous body cannot hold either light or heat, as we shew elsewhere more than once under the appropriate headings. Finally the bases of the two opposed primal active qualities  must similarly be enduring; and the sun by virtue of those parts which are bright and hot must be like a stone, or a most solid incandescent metal;  not a fusible metal as lead, bronze, gold or silver, but an infusible; not indeed a glowing iron but that iron which is itself a flame; so that even as this star on which we dwell is cold in herself and dark, not participating in heat or light except insofar as she is heated by the sun, so the sun is in itself hot and bright, and participateth not at all in cold and darkness except as he is chilled by the surrounding bodies and containeth particles of water, even as our earth containeth particles of fire. Therefore, as in this most frigid body primarily cold and dark, there dwell animals which live by the heat and light of the sun, so in that most torrid and shining body there are beings which can vegetate by aid of the chill from surrounding cold bodies; and as our earth hath a certain participation in heat in her dissimilar parts, so also hath the sun a certain participation in cold throughout his parts.
Elpino. But what of light?
Philotheo. I say that the sun shineth not on the sun nor the earth on the earth, nor any body on itself, but that every shining body doth illumine the space around itself. Indeed, though the earth be bright owing to the rays of the sun striking her crystalline surface, yet her light cannot be perceived by us, or by anyone on this surface, but only by those who are opposite thereto. Moreover though the whole surface of the sea be illumined at night by the splendour of the moon, yet to those traversing the sea, this effect is not apparent except in a certain region opposite to the moon. But if they could rise further above the sea, then the extent of the illuminated surface would appear to them to increase; and the further they rose, the greater illuminated space they would see. It can thus easily be inferred that the inhabitants of bright or even of illumined stars do not perceive the light of their own but only that of the surrounding stars, just as within a single area, one particular part will be illumined from another.
Elpino. Thus you would say that solar creatures derive daylight not from the sun but from another neighbouring star?
Philotheo. Even so. Do you not understand this?
Elpino. Who would not? Moreover, contemplating this matter I come somewhat to understand others which follow therefrom. There are then two sorts of bright bodies, fiery bodies which give their own primary light, and aqueous or crystalline bodies which give reflected or secondary light.
Philotheo. That is so.
Elpino. Then the cause of our light should be referred to no other source than these two?
Philotheo. How can it be otherwise since we know of no other source of light? Why should we trust to vain fantasies when experience herself doth teach us?
Elpino. It is true that we cannot imagine those bodies to have light merely by reason of intermittent accident, such as putrefaction of wood, scales and viscous incrustation of fish, or that most fragile back of a glow-worm concerning the cause of whose light we will speak on other occasions.
Philotheo. As you like.
Elpino. They therefore err who describe the outer surrounding bright bodies as certain fifth essences, certain divine corporeal substances of a nature contrary from that of the bright bodies which are near to us; herein they err no less than would those who would describe thus a candle or a bright crystal seen from afar.
Fracastoro. This indeed conformeth with our every perception, our reason and mind.
Burchio. Not however with mine, which would easily judge this your demonstration to be a gentle exercise in Sophistry.
Philotheo. Fracastoro, do thou reply to him, for Elpino and I who have spoken much will listen to thee.
Fracastoro. My dear Burchio, for my part I will regard thee as Aristotle, and I will take the part of an idiot and a rustic who doth confess to complete ignorance. It must be supposed that I have understood naught of the words or meanings either of Philotheo, or of Aristotle and the rest of the world. I believe the verdict of the multitude, I believe in the fame and majesty of the supreme Peripatetic authority; I join an innumerable multitude in adoring the divinity of this veritable portent of nature, and for that reason I have come to thee to teach me the truth and to free me from the persuasive pressure of him whom thou hast called a sophist. Well, I ask you,  why have you said that there is very much, or much, or what you will, of difference between those distant celestial bodies and these which are close to us?
Burchio. Those are divine, these compound of matter.
Fracastoro. How can you make me see and believe that those are more divine?
Burchio. Because they are changeless, unalterable, incorruptible, and eternal, while these near us have the contrary qualities; those move with a perfect circular motion, these in straight lines.
Fracastoro. I would like to know whether, after careful consideration, thou wouldst affirm on oath that this body alone (which thou regardest as three or four bodies and not as members of a single complex) is not mobile as the other stars are mobile, it being accepted that the motion of those stars is imperceptible because we are removed beyond a certain distance from them. And their motion, if it doth occur, cannot be perceived by us, because, as hath been observed both by the ancients and by the moderns who have truly contemplated nature, and as experience manifesteth in a thousand ways to our perception, we cannot apprehend motion except by a certain comparison and relation with some fixed body. Wherefore if we suppose a person within a moving ship in the midst of waters, who knoweth not that the water is in motion, nor seeth the shores, he would be unaware of the motion of the ship. For this reason I might fall into doubt and hesitation as to this quiet and fixity [of our earth]; and I am able to believe that if I were on the sun, the moon or any other star, I should always imagine myself to be at the centre of a motionless world around which would seem to revolve the whole surrounding universe, though in truth the containing body on which I found myself would be spinning around its own centre. Thus I can feel no certitude of the distinction between a moving and a stable body. As to what thou sayest concerning motion in a straight line, we certainly cannot see our own body moving thus along a straight line, nor can we see others do so. If the earth moveth, she must have circular motion like that of other stars as is said by Hegesias,  Plato and all learned men, and as Aristotle and everyone else should admit; and that part of the earth which we see ascending and descending is not the whole globe but certain particles thereof which do not recede beyond that region which is reckoned as a part of this globe. For as in an animal, so in this our world there is an influx and efflux of the particles, a certain vicissitude, a certain change and renewal. And if all this happeneth likewise in other stars, it followeth not that the process must be perceptible to us. For rising of vapours and exhalations, successions of winds, rains, snows, thunder, sterility, fertility, inundations, birth, death -- if these take place in the other stars, they similarly are not perceptible to us; only the stars themselves are perceptible to us owing to the continuous splendour which from a surface either of fire, of water or of cloud they send forth into wide space. Similarly our own star is perceptible to inhabitants of other stars by reason of the splendour which she diffuseth from the surface of the seas -- and sometimes also from the revolution of nebulous bodies, as the opaque portions of the moon appear for the same reason less opaque. The aspect of these surfaces is changed only at vast intervals of eras and centuries, in the course of which seas are changed to continents, continents to seas.  Therefore our globe as well as those others are perceptible on account of the light they diffuse. The light which our earth diffuseth to other stars is neither more nor less eternal and changeless than that from other similar stars. And just as the motion in a straight line and alteration of their particles is imperceptible to us, so every other motion and every change which may happen to our world is imperceptible from those other worlds. Now just as from our earth (itself a moon) the diverse parts of the moon appear some more and some less bright -- so from the moon (itself another earth) can the diverse parts of this earth be distinguished by the variety and difference of the portions of her surface. Moreover just as, if the moon were at a greater distance from us, then the diameter of the opaque parts would fail, while the bright parts would tend to unite for us and shrink in our view, giving us the impression of a smaller body of uniform brightness, similar also would be the appearance of our earth as seen from the moon if the distance between them were greater. Wherefore we may suppose that of the innumerable stars some are moons, some terrestrial globes, some worlds like our own, and around them our earth appeareth in their eyes to revolve just as they appear to us to revolve and to take their course around the earth. Why then should we affirm a difference between our own and those other heavenly bodies if we find every similarity between them [lit., every convenience (in recognizing their similarity)]? And why should we deny that there is a similarity [lit., this convenience] when neither reason nor sense-perception should lead us to doubt it?
Burchio. So you consider it proven that these bodies do not differ from our own earth?
Fracastoro. Full well. For that which can be seen from them of our own world can be seen of them from here, and that which can be seen of them from here can be seen of our world by them. Namely, this appeareth a small body even as do those, each appearing bright in parts from a shorter distance, each appearing uniformly bright and smaller from a greater distance.
Burchio. Where then is that beautiful order, that lovely scale of nature rising from the denser and grosser body which is our earth, to the less dense [sphere] which is water and on to the subtle [sphere] which is vapour, to the yet subtler which is pure air, on to the subtlest which is fire and finally to the divine which is the celestial body? From the obscure to the less obscure, to the brighter and finally to the brightest? From the dark to the most brilliant, from the alterable and corruptible to liberation from all change and corruption? From the heaviest to the heavy, thence to the light, on to the lightest and finally to that which is without weight or lightness? From that which moveth toward the centre to that which moveth from the centre and then to that which moveth around the centre?
Fracastoro. You would like to know where is this order? In the realm of dreams, fantasies, chimeras, delusions. For, as to motion, everything endowed with natural motion revolveth in a circle around either his own or some other centre. I speak of revolution, not having regard simply to the geometrical circle and circular motion, but according to that law which we observe to govern the physical changes in the position of natural bodies. Motion in a straight line is neither innate nor natural to any prime body, for it is never seen except in those particles which are either as excrement flowing from mundane bodies or else entering from outside into kindred spheres and containing bodies; even as we see waters which becoming subtilized through heat rise upward as vapour, and then condensed by the cold return downward in their original form. We shall speak of this process in the appropriate place when we consider motion. As for the disposition of the four bodies which they name earth, water, air, fire, I would know what nature, what art, what perception maketh it, verifieth and showeth it?
Burchio. Then you deny the famous distinction of the elements?
Fracastoro. I deny not the distinction of the elements, for I leave everyone at liberty to distinguish as he pleaseth concerning natural things. But I deny this order, this disposition that the earth is surrounded and contained by water, water by air, air by fire, fire by the heaven. Because I say there is but one single container that comprehendeth all bodies and those great frames which appear to us as scattered and sparse in this vast field, wherein every one of those bodies, stars, worlds and eternal lights is composed of that which is named earth, water, air and fire. Those in the substance of whose composition fire doth predominate, will be called sun, bright in itself; if water doth predominate, we give the name tellurid body, moon or such like which shineth by borrowed light, as hath been said. In these stars then or worlds as we will call them, these dissimilar parts must be understood to be disposed according to their various and diverse complexions of rocks, pools, streams, springs, seas, sands, metals, caverns, mountains, plains and other similar sorts of composite bodies, sites and shapes; in the same fashion among animals the parts are named heterogeneous according to the diverse and varied complexions of bones, intestines, veins, arteries, flesh, nerves, lungs, members of one or another shape presenting their excrescences, hollows, caves, waters, spirits, fires, with the accidents corresponding to all meteoric impressions, such as catarrhs, inflammations, stones, vertigoes, fevers and innumerable other dispositions and qualities corresponding to mists, rains, snows, heats, lightnings, thunderbolts, thunders, earthquakes and winds, tempests, torrid or that toss sea-weed.
If then the earth and other worlds are animals not such as these creatures are commonly esteemed, then indeed they are animals with greater and more excellent mind than belongs usually to these creatures. How then can Aristotle or another prove the air to be rather around than within our earth, if there is no part of the earth in which the air doth not lurk and penetrate in the manner which perhaps the ancients meant by saying that the Void embraceth all from without and moreover doth interpenetrate the whole Plenum? How then can you imagine the earth to have thickness, density and consistency without water which linketh and uniteth the parts? How can you interpret the earth's being heavier toward its centre except by believing that the parts there are closer and denser, such density being impossible without water which alone can join part to part?
Who doth not see that over the whole earth there emerge islands and mountains above the water, and not only above the water but also above the misty and tempestuous airs which are shut in among high mountains and considered as parts of the earth that go to make up her perfect sphericity? So it is evident that waters exist within the earth's viscera even as within us are humors and blood.  Who doth not know that the chief accumulations of water are deep caverns and concavities of the earth? And if thou sayest that the earth is sodden on her shores, I reply that these are not the higher portions of the earth, for all that which formeth part of even her highest mountains is understood to be also within her concavity. Moreover the same may be observed of drops covered with dust but hanging unbroken over a surface. For the intimate soul which both embraceth and interfuseth all things first performeth this operation, namely that, in so far as possible and according to the capacity of each subject, she uniteth the parts  thereof. Nor is this because water either is or can be of its nature above or around the earth, any more than the moisture of our human substance is above or around our body.
I leave aside the fact that from every part of the shore and from all great stretches of water, the surface of the water is observed to be higher in the centre: and if the parts of the dry land could thus unite, they would undoubtedly do the same, as indeed they clearly do assume the form of spherical globes when, by the aid of water, they are united, for all cohesion and viscosity of parts in the air is due to moisture. Since then waters exist within the bowels of the earth, and since every part of that earth which is cohesive and endowed with viscosity containeth more of moisture than of dry matter (for indeed, where is most viscosity there is most intermixture and domination by water which hath the quality of cohesion of the parts), who then will not declare rather that water is the basis of earth than earth of water? Rather that earth is founded on water than water on earth?
I leave aside the fact that the depth of water above the surface of our earth, namely the sea, cannot be and is not of so great a volume as even to compare with the volume of the whole sphere: it is in fact not around, as fools believe, but is within the earth as indeed Aristotle confessed in the first book of his Meteorologica, being compelled by truth or indeed by the customary belief among ancient philosophers; for he admitted that the two lower regions of turbulent and unquiet air are intercepted and contained by high mountains, and are as parts and members of the earth;  and the whole is surrounded and contained by air which is ever tranquil, serene and clear when seen from the stars, so that when they [in the stars] lower their eyes [to the earth] they perceive all the winds, clouds, mists, tempests, the ebb and the flow, which proceed from the life and breath of this great animal, this divinity that we call the Earth, which hath been named Ceres, figured as Isis, entitled Proserpine and Diana, and is the same which is called Lucina in the heaven; all these being understood as of one and the same nature with the Earth. Behold, too, how far is the good Homer, when he noddeth not,  from affirming the natural site of water to be above or around the earth where there are no winds nor rains nor foggy influences. And if he [Aristotle] had considered and pondered a little further, he would have perceived that even at the centre of our earth (if that is indeed the centre of gravity) there occurreth more of water than of dry earth. For the particles of the earth are only heavy when mixed with much water; without water they have no aptness through their own impulse and weight to descend from the air to the sphere to which they belong. What disciplined sense, what truth of nature distinguisheth and marshaleth these particles in such a manner as is imagined by the blind and foul vulgar folk, approved by those who speak without reflection, preached by those who talk much and think little? Moreover, who will deny the truth of Plato's opinion as recorded in the Timaeus and by Pythagoras and others -- though if propounded by a man of no standing, it would be deemed laughable; if by a person of some renown and proved ability, it would be regarded as a mystery or parable and interpreted metaphorically; if by a man of more sense and intellect than authority it would be reckoned among the occult paradoxes. For the opinion is that we inhabit the dark concavity of the earth, and that our nature appeareth to the living beings above the earth as doth that of the fish to us;  that as the fish live in a humid element denser and crasser than our own, so we live in a more foggy air than do those in the purer and more tranquil region; and as Ocean is mere water compared even to impure air, so is our dark air to that which is truly pure. From all this I would argue as follows: that the sea, springs, rivers, mountains, rocks and the air contained within them and held by them as far as their medial region  (as it is said) are no other than dissimilar members and parts of a single body, a single mass, comparable and proportionate to the parts and members with which we are all familiar in the composition of living bodies; the limits, convexity and outer surfaces of this body [which is our earth] are terminated by the edges of mountains, and by tempestuous air, so that the Ocean and streams remain in the depths of the earth, just as the liver which is believed to be the ultimate spring of the blood, and the branching veins are contained and distended by the several parts [of the animal body].
Burchio. Then the earth is not the heaviest body and therefore in the centre? Nor is the next in weight and position the water which surroundeth it, and is heavier than air?
Fracastoro. If thou judgest weight by a greater aptness to interpenetrate parts and to reach to the midst, and from the central position, I will say that air is both the heaviest and also the lightest of all the so-called elements. For as every particle of earth, given the space, descendeth to the centre, so also the particles of air rush to the centre even more swiftly than the particles of any other body whatsoever; for it pertaineth to air to be first to occupy space and to prevent and fill a void; the particles of earth do not change their position with such speed, for they do not usually move except if penetrated by air; since for penetration by air, there is needed neither earth, water nor fire; neither do any of these forestall or vanquish air, nor exceed it in disposition or speed to fill every corner of the containing body. Moreover, if earth, which is a solid body, is removed, 'tis air that will fill the place thereof; but earth is not so apt to occupy space vacated by air. Since therefore it is the property of air to rush to penetrate every site and every remote corner, there is no body lighter than air, nor is any body heavier than air.
Burchio. What then willst thou say of water?
Fracastoro. I have said and I repeat that water is heavier than earth. For we observe that moisture is more powerfully disposed to descend and to penetrate to the very centre of dry earth than is the dry earth to penetrate water. Moreover, dry earth, if entirely unmixed with water, will float on the surface of water without any aptness to penetrate within; nor will it descend until imbued with water and condensed thereby into a cohesive mass; only by dint of this cohesion and density can it penetrate within and below the water; while water, on the contrary, never descendeth by the assistance of earth but because itself doth aggregate, condense and multiply the number of its particles so that it may be sucked up and may thus gather together the dry earth. For we observe that a vase filled with really dry ashes holdeth more water than doth an empty vase of the same size. The dry particles as such float on the surface of water.
Burchio. Describe this further to me.
Fracastoro. I repeat: if all water were to be removed from the earth so as to leave it completely dry, the result would be a body of no endurance, fine, friable, and easily dispersed throughout the air as innumerable discrete bodies. For whereas air formeth [of itself] a continuum, it is water that formeth [another body into] a continuum by means of cohesion, and the substance of this continuous body may be what you will, but will be cohesive and solid, sometimes of one matter, sometimes of another, sometimes a mixture. Since then weight resulteth solely from cohesion and density of particles, and since the particles of earth do not cohere to one another save by the aid of water, whose particles like those of air do spontaneously cohere; and since water hath, more than aught else if not in unique fashion, the power of endowing with cohesion the particles of other bodies -- it therefore followeth that water is pre-eminently heavy as compared to other bodies which derive their weight from it. Wherefore those who affirm that the earth is established on the waters should by no means be regarded as fools but rather as most wise.
Burchio. We, however, maintain that the earth should always be regarded as central, as hath been believed by so many highly learned personages.
Fracastoro. And hath been confirmed by fools.
Burchio. What do you say of fools?
Fracastoro. I say that this opinion hath not been confirmed either by sense or reason.
Burchio. Do we not see the ebb and flow of the seas, and the course of rivers over the surface of the earth?
Fracastoro. But the springs which give origin to the rivers, and form lakes and seas, do we not see them emerge from the bowels of the earth and yet not issue beyond the bowels of the earth -- if indeed thou hast rightly understood what I have repeatedly said a short time back?
Burchio. We see that the waters first descend from the air, and that springs are formed from these waters.
Fracastoro. We know that water, if indeed it descendeth from another atmosphere than that which appertaineth to the members of the earth, yet is primarily, originally, principally and totally within the earth, and only later, derivatively, secondarily and partially in the air.
Burchio. I know that thou standest on this principle that the true estimate of the ultimate convex surface of the earth should be based not on the ocean surface but on the atmosphere level with the highest mountains.
Fracastoro. So indeed your leader Aristotle both stated and confirmed.
Burchio. Our leader is indeed without comparison more celebrated, worthy and famed than yours who is yet to be known and seen. Wherefore, rejoice as you will in yours. I, however, am content with mine.
Fracastoro. Even though he leaveth you to die of hunger and cold, though he feedeth you with wind and sendeth you forth naked and barefoot.
Philotheo. Pray do not dally with such useless and idle propositions.
Fracastoro. So be it. Burchio, what then do you say to all that you have heard?
Burchio. I say that everyone, whoever he be, must ultimately see what is in the midst of this mass -- thy star, thine animal. For if it be indeed pure earth, then the order in which these philosophers have ranged the elements is no vain imagination.
Fracastoro. I have stated and demonstrated that the midst is far more probably air or water than dry earth -- and indeed such dry earth cannot reach thereto without considerable admixture of waters which ultimately become its foundation; for we see that the particles of water penetrate the earth with far more vigour than do particles of earth penetrate water. It is then more probable and indeed inevitable that there should be water in the bowels of the earth rather than earth in the depths of water.
Burchio. What dost thou say of the waters which float and wander over the earth?
Fracastoro. None can fail to observe that this process taketh place by virtue of the same water, which having thickened and given cohesion to the earth, pressing together the parts thereof, thereby preventeth the further absorption of the waters, which would otherwise penetrate to the depth of the arid substance, as we see by universal experience. Water then must be at the centre of the earth to give to it that firmness which must depend not on primordial earth, but on water; for water uniteth and joineth the earth's particles; it followeth therefore that water causeth the density of the earth rather than the contrary, that earth giveth cohesion and density to the particles of water. But if thou wilt not accept that the central part of the earth is a mixture of earth and water, then it is more probable and conformable to all reason and experience that it should be water rather than earth. And if a dense body, it is more reasonable to conclude that water rather than dry earth predominateth; for water endoweth the particles of the earth with cohesion, for otherwise the earth would dissolve on account of the heat (not that I would postulate thus of the density of primordial fire which can be dissolved by its contrary). For the more dense and heavy is earthy matter, the more assuredly is it mixed with water. Wherefore the densest of those things which we know, we deem not merely to be those most mixed with water, but to be of the very substance of water, as is shewn when the heaviest and densest of all bodies, namely liquefiable metals, become molten. And indeed in every solid body whose particles cohere, we must presume the water which doth unite and join the parts, even the minima naturae; so that dry earth completely free from water is naught but wandering and scattered atoms. The particles of water are indeed more cohesive if unmixed with earth, since the earth particles have no cohesion without the aid of water. If then the central position is reserved for that which seeketh it with the strongest and swiftest impulse, it appertaineth first to air which filleth all, then to water, and only thirdly to earth; if it belongeth to that which is most heavy, dense and thick, then it appertaineth first to water, secondly to air and thirdly to dry earth. If we consider dry earth mixed with water, the central position appertaineth first to earth, second to water and third to air. So that according to various diverse arguments, the central position is variously assigned; according to truth and nature, no element is found without another, and there is no member of this great animal the earth in which are not all four, or at least three elements.
Burchio. Quickly, your conclusion!
Fracastoro. I would conclude as follows. The famous and received order of the elements and of the heavenly bodies is a dream and vainest fantasy, since it can neither be verified by observation of nature nor proved by reason or argued, nor is it either convenient or possible to conceive that it exist in such fashion. But we know that there is an infinite field, a containing space which doth embrace and interpenetrate the whole. In it is an infinity of bodies similar to our own. No one of these more than another is in the centre of the universe, for the universe is infinite and therefore without centre or limit, though these appertain to each of the worlds within the universe in the way I have explained on other occasions, especially when we demonstrated that there are certain determined definite centres, namely, the suns, fiery bodies around which revolve all planets, earths and waters, even as we see the seven wandering planets take their course around our sun. Similarly we shewed that each of these stars or worlds, spinning around his own centre, hath the appearance of a solid and continuous world which taketh by force all visible things which can become stars and whirleth them around himself as the centre of their universe. Thus there is not merely one world, one earth, one sun, but as many worlds as we see bright lights around us, which are neither more nor less in one heaven, one space, one containing sphere than is this our world in one containing universe, one space or one heaven. So that the heaven, the infinitely extending air, though part of the infinite universe, is not therefore a world or part of worlds; but is the womb, the receptacle and field within which they all move and live, grow and render effective the several acts of their vicissitudes; produce, nourish and maintain their inhabitants and animals; and by certain dispositions and orders they minister to higher nature, changing the face of single being through countless subjects. Thus each of these worlds is a centre toward which convergeth every one of his own parts; toward it every kindred thing doth tend just as the parts of this our star, even though at a certain distance, are yet brought back to their own field from all sides of the surrounding region. Therefore, since no part which floweth thus outward from the great Body faileth ultimately to return thereto; it happeneth that every such world is eternal though dissoluble; albeit if I mistake not, the inevitability of such eternity dependeth on an external maintaining and provident Being and not on intrinsic power and self-sufficiency. But I will explain you this matter with special arguments on other occasions.
Burchio. Then the other worlds are inhabited like our own?
Fracastoro. If not exactly as our own, and if not more nobly, at least no less inhabited and no less nobly. For it is impossible that a rational being fairly vigilant, can imagine that these innumerable worlds, manifest as like to our own or yet more magnificent, should be destitute of similar and even superior inhabitants; for all are either themselves suns or the sun doth diffuse to them no less than to us those most divine and fertilizing rays, which convince us of the joy that reigneth at their source and origin and bring fortune to those stationed around who thus participate in the diffused quality. The innumerable prime members of the universe are then infinite [in number], and all have similar aspect, countenance, prerogative, quality and power.
Burchio. You will not admit any difference between them?
Fracastoro. [On the contrary]. You have heard more than once that some, in whose composition fire doth predominate, are by their own quality bright and hot. Others shine by reflection, being themselves cold and dark, for water doth predominate in their composition. On this diversity and opposition depend order, symmetry, complexion,  peace, concord, composition and life. So that the worlds are composed of contraries of which some, such as earth and water, live and grow by help of their contraries,  such as the fiery suns. This I think was the meaning of the sage who declared that God createth harmony out of sublime contraries;  and of that other who believed this whole universe to owe existence to the strife of the concordant and the love of the opposed. 
Burchio. In this way, you would put the world upside down.
Fracastoro. Wouldst thou consider him to do ill who would upset a world which was upside down?
Burchio. Would you then render vain all efforts, study and labours on such work as De physico auditu and De coelo et mondo wherein so many great commentators, paraphrasers, glossers, compilers, epitomizers, scholiasts, translators, questioners and logicians have puzzled their brains? Whereon profound doctors, subtle, golden, exalted, inexpugnable irrefragable, angelic, seraphic, cherubic and divine, have established their foundation?
Fracastoro. Add the stonebreakers, the rocksplitters, horn-footed highkickers.  Add also the deep seers, know-alls,  the Olympians, the firmamenticians, celestial empirics, loud thunderers.
Burchio. Should we cast them all at your suggestion into a cesspool? The world will indeed be ruled well if the speculations of so many and such worthy philosophers are to be cast aside and despised.
Fracastoro. It were not well that we should deprive the asses of their fodder, and wish them to adopt our own taste. Talent and intellect vary no less than temperaments and stomachs.
Burchio. You maintain that Plato is an ignorant fellow, Aristotle an ass and their followers insensate, stupid and fanatical?
Fracastoro. My son, I do not say these are foals and those asses, these little monkeys and those great baboons, as you would have me do. As I told you from the first, I regard them as earth's heroes. But I do not wish to believe them without cause, nor to accept those propositions whose antitheses (as you must have understood if you are not both blind and deaf) are so compellingly true.
Burchio. Who then shall be judge?
Fracastoro. Every well-regulated mind and alert judgement. Every discreet person who is not obstinate when he recognizeth himself convinced and unable either to defend their arguments or to resist ours.
Burchio. When I can no longer defend them, it will be the fault of my inadequacy, not of their doctrine; when you are able while attacking their doctrine to clinch your own, it will not be by the truth of your doctrine but by your importunate sophistries.
Fracastoro. If I knew myself ignorant of the principles, I should abstain from pronouncing judgement. If I felt so deeply as you on the matter, I should regard resell as instructed by faith, not by knowledge.
Burchio. If thou wert better endowed, thou wouldst recognize thyself to be a presumptuous ass, a sophist, a disturber of good letters, a murderer of talent, a lover of novelty, an enemy of truth, suspect of heresy.
Philotheo. So far that fellow hath shown himself poorly instructed. Now he will demonstrate that he is dowered with but little discretion and no manners.
Elpino. He hath a loud voice and could not dispute more hardily if he were of the clog-shod brotherhood?  Burchio, my dear fellow, warmly do I praise the constancy of thy faith. From the very beginning thou hast said that even though true, thou wouldst not believe it.
Burchio. It is so. I would prefer ignorance in the great company of the illustrious and the learned rather than knowledge with a few sophists, as I must deem these friends.
Fracastoro. Thou hast little skill to distinguish between the learned and sophists, if we must believe what thou hast said. The ignorant are not illustrious and learned, nor are those who know to be called sophists.
Burchio. I know that you understand what I would say.
Elpino. It would be a great deal could we understand what you say. For you yourself have hard work to understand what you would say.
Burchio. Go to, go to, ye who are more learned than Aristotle. Depart, ye who are more divine than Plato, more profound than Averroes, more judicious than so many philosophers and theologians of all ages and all nations who have commented, admired and raised him to heaven. Away with you. I know not who ye are, nor whence ye come, but ye would presume to set yourselves in opposition to the overwhelming opinion of so many great doctors.
Fracastoro. If that were an argument, it would be the best of all you have brought forward.
Burchio. Thou wouldst be more learned than Aristotle wert thou not a beast, destitute, a beggar, miserable, fed on millet bread, dead with hunger, born of a tailor and a washerwoman, nephew of Neddy  the cobbler, son of Momus, postilion of whores, brother of Lazarus who shoes the asses. Remain a hundred devils, you who are not much better than he.
Elpino. I pray you, magnificent Sir, do not trouble yourself to return to us, but await our coming to you.
Fracastoro. To demonstrate truth with further arguments to such fellows, 'twould be as though repeatedly to wash with varied soaps and sodas the head of an ass, which profiteth no more to be washed a hundred times than once, in a thousand fashions than in one, since washed or unwashed, he is unchanged.
Philotheo. Moreover such a head will always appear more foul after a washing than before, for by adding more and more water and perfumes, the fumes within that head become at the end more and more agitated, and that noisome stench becometh noticeable which hitherto passed unnoticed, for it will be the more repulsive, the more it is revealed in contrast to aromatic liquors. We have spoken much to-day. I rejoice greatly in the intelligence of Fracastoro and in your mature judgement, O Elpino. Now that we have discoursed concerning the existence, the number and quality of the infinite worlds, it is well that to-morrow we see whether and of what sort may be the contrary arguments.
Elpino. So be it.
End of the Third Dialogue.