(6) We return, then, to the question whether there could be light if there were no air, the sun illuminating corporeal surfaces across an intermediate void which, as things are, takes the light accidentally by the mere fact of being in the path. Supposing air to be the cause of the rest of things being thus affected, the substantial existence of light is due to the air; light becomes a modification of the air, and of course if the thing to be modified did not exist neither could be modification.

The fact is that primarily light is no appanage of air, and does not depend upon the existence of air: it belongs to every fiery and shining body, it constitutes even the gleaming surface of certain stones.

Now if, thus, it enters into other substances from something gleaming, could it exist in the absence of its container?

There is a distinction to be made: if it is a quality, some quality of some substance, then light, equally with other qualities, will need a body in which to lodge: if, on the contrary, it is an activity rising from something else, we can surely conceive it existing, though there be no neighbouring body but, if that is possible, a blank void which it will overleap and so appear on the further side: it is powerful, and may very well pass over unhelped. If it were of a nature to fall, nothing would keep it up, certainly not the air or anything that takes its light; there is no reason why they should draw the light from its source and speed it onwards.

Light is not an accidental to something else, requiring therefore to be lodged in a base; nor is it a modification, demanding a base in which the modification occurs: if this were so, it would vanish when the object or substance disappeared; but it does not; it strikes onward; so, too it would always have its movement.

But movement, where?

Is space, pure and simple, all that is necessary?

With unchecked motion of the light outward, the material sun will be losing its energy, for the light is its expression.

Perhaps; and we may gather that the light never was an appanage of anything, but is the expressive Act proceeding from a base but not seeking to enter into a base, though having some operation upon any base that may be present.

Life is also an Act, the Act of the soul, and it remains so when anything- the human body, for instance- comes in its path to be affected by it; and it is equally an Act though there be nothing for it to modify: surely this may be true of light, one of the Acts of whatever luminary source there be . Certainly light is not brought into being by the dark thing, air, which on the contrary tends to gloom it over with some touch of earth so that it is no longer the brilliant reality: as reasonable to talk of some substance being sweet because it is mixed with something bitter.

If we are told that light is a mode of the air, we answer that this would necessarily imply that the air itself is changed to produce the new mode; in other words, its characteristic darkness must change into non-darkness; but we know that the air maintains its character, in no wise affected: the modification of a thing is an experience within that thing itself: light therefore is not a modification of the air, but a self-existent in whose path the air happens to be present.

On this point we need dwell no longer; but there remains still a question.

(7) We can scarcely do better, in fine, than follow Plato.

Thus:

In the universe as a whole there must necessarily be such a degree of solidity, that is to say, of resistance, as will ensure that the earth, set in the centre, be a sure footing and support to the living beings moving over it, and inevitably communicate something of its own density to them: the earth will possess coherence by its own unaided quality, but visibility by the presence of fire: it will contain water against the dryness which would prevent the cohesion of its particles; it will hold air to lighten its bulky matters; it will be in contact with the celestial fire- not as being a member of the sidereal system but by the simple fact that the fire there and our earth both belong to the ordered universe so that something of the earth is taken up by the fire as something of the fire by the earth and something of everything by everything else.

This borrowing, however, does not mean that the one thing taking-up from the other enters into a composition, becoming an element in a total of both: it is simply a consequence of the kosmic fellowship; the participant retains its own being and takes over not the thing itself but some property of the thing, not air but air's yielding softness, not fire but fire's incandescence: mixing is another process, a complete surrender with a resultant compound not, as in this case, earth- remaining earth, the solidity and density we know- with something of fire's qualities superadded.

We have authority for this where we read:

"At the second circuit from the earth, God kindled a light": he is speaking of the sun which, elsewhere, he calls the all-glowing and, again, the all-gleaming: thus he prevents us imagining it to be anything else but fire, though of a peculiar kind; in other words it is light, which he distinguishes from flame as being only modestly warm: this light is a corporeal substance but from it there shines forth that other "light" which, though it carries the same name, we pronounce incorporeal, given forth from the first as its flower and radiance, the veritable "incandescent body." Plato's word earthy is commonly taken in too depreciatory a sense: he is thinking of earth as the principle of solidity; we are apt to ignore his distinctions and think of the concrete clay.

Fire of this order, giving forth this purest light, belongs to the upper realm, and there its seat is fixed by nature; but we must not, on that account, suppose the flame of earth to be associated with the beings of that higher sphere.

No: the flame of this world, once it has attained a certain height, is extinguished by the currents of air opposed to it. Moreover, as it carries an earthy element on its upward path, it is weighed downwards and cannot reach those loftier regions. It comes to a stand somewhere below the moon- making the air at that point subtler- and its flame, if any flame can persist, is subdued and softened, and no longer retains its first intensity, but gives out only what radiance it reflects from the light above.

And it is that loftier light- falling variously upon the stars; to each in a certain proportion- that gives them their characteristic differences, as well in magnitude as in colour; just such light constitutes also the still higher heavenly bodies which, however, like clear air, are invisible because of the subtle texture and unresisting transparency of their material substance and also by their very distance.

(2) If sight depends upon the linking of the light of vision with the light leading progressively to the illumined object, then, by the very hypothesis, one intervening substance, the light, is indispensable: but if the illuminated body, which is the object of vision, serves as an agent operating certain changes, some such change might very well impinge immediately upon the eye, requiring no medium; this all the more, since as things are the intervening substance, which actually does exist, is in some degree changed at the point of contact with the eye .

Those who have made vision a forth-going act need not postulate an intervening substance- unless, indeed, to provide against the ray from the eye failing on its path- but this is a ray of light and light flies straight. Those who make vision depend upon resistance are obliged to postulate an intervening substance.

The champions of the image, with its transit through a void, are seeking the way of least resistance; but since the entire absence of intervenient gives a still easier path they will not oppose that hypothesis.

So, too, those that explain vision by sympathy must recognize that an intervening substance will be a hindrance as tending to check or block or enfeeble that sympathy; this theory, especially, requires the admission that any intervenient, and particularly one of kindred nature, must blunt the perception by itself absorbing part of the activity. Apply fire to a body continuous through and through, and no doubt the core will be less affected than the surface: but where we are dealing with the sympathetic parts of one living being, there will scarcely be less sensation because of the intervening substance, or, if there should be, the degree of sensation will still be proportionate to the nature of the separate part, with the intervenient acting merely as a certain limitation; this, though, will not be the case where the element introduced is of a kind to overleap the bridge.

But this is saying that the sympathetic quality of the universe depends upon its being one living thing, and that our amenability to experience depends upon our belonging integrally to that unity; would it not follow that continuity is a condition of any perception of a remote object?

The explanation is that continuity and its concomitant, the bridging substance, come into play because a living being must be a continuous thing, but that, none the less, the receiving of impression is not an essentially necessary result of continuity; if it were, everything would receive such impression from everything else, and if thing is affected by thing in various separate orders, there can be no further question of any universal need of intervening substance.

Why it should be especially requisite in the act of seeing would have to be explained: in general, an object passing through the air does not affect it beyond dividing it; when a stone falls, the air simply yields; nor is it reasonable to explain the natural direction of movement by resistance; to do so would bring us to the absurdity that resistance accounts for the upward movement of fire, which on the contrary, overcomes the resistance of the air by its own essentially quick energy. If we are told that the resistance is brought more swiftly into play by the very swiftness of the ascending body, that would be a mere accidental circumstance, not a cause of the upward motion: in trees the upthrust from the root depends on no such external propulsion; we, too, in our movements cleave the air and are in no wise forwarded by its resistance; it simply flows in from behind to fill the void we make.

If the severance of the air by such bodies leaves it unaffected, why must there be any severance before the images of sight can reach us?

And, further, once we reject the theory that these images reach us by way of some outstreaming from the objects seen, there is no reason to think of the air being affected and passing on to us, in a progression of impression, what has been impressed upon itself.

If our perception is to depend upon previous impressions made upon the air, then we have no direct knowledge of the object of vision, but know it only as through an intermediary, in the same way as we are aware of warmth where it is not the distant fire itself that warms us, but the warmed intervening air. That is a matter of contact; but sight is not produced by contact: the application of an object to the eye would not produce sight; what is required is the illumination of the intervening medium; for the air in itself is a dark substance: If it were not for this dark substance there would probably be no reason for the existence of light: the dark intervening matter is a barrier, and vision requires that it be overcome by light. Perhaps also the reason why an object brought close to the eye cannot be seen is that it confronts us with a double obscuration, its own and that of the air.

(4) But there is the question of the linked light that must relate the visual organ to its object.

Now, firstly: since the intervening air is not necessary- unless in the purely accidental sense that air may be necessary to light- the light that acts as intermediate in vision will be unmodified: vision depends upon no modification whatever. This one intermediate, light, would seem to be necessary, but, unless light is corporeal, no intervening body is requisite: and we must remember that intervenient and borrowed light is essential not to seeing in general but to distant vision; the question whether light absolutely requires the presence of air we will discuss later. For the present one matter must occupy us:

If, in the act of vision, that linked light becomes ensouled, if the soul or mind permeates it and enters into union with it, as it does in its more inward acts such as understanding- which is what vision really is- then the intervening light is not a necessity: the process of seeing will be like that of touch; the visual faculty of the soul will perceive by the fact of having entered into the light; all that intervenes remains unaffected, serving simply as the field over which the vision ranges.

This brings up the question whether the sight is made active over its field by the sheer presence of a distance spread before it, or by the presence of a body of some kind within that distance.

If by the presence of such a body, then there will be vision though there be no intervenient; if the intervenient is the sole attractive agent, then we are forced to think of the visible object as being a Kind utterly without energy, performing no act. But so inactive a body cannot be: touch tells us that, for it does not merely announce that something is by and is touched: it is acted upon by the object so that it reports distinguishing qualities in it, qualities so effective that even at a distance touch itself would register them but for the accidental that it demands proximity.

We catch the heat of a fire just as soon as the intervening air does; no need to wait for it to be warmed: the denser body, in fact, takes in more warmth than the air has to give; in other words, the air transmits the heat but is not the source of our warmth.

When on the one side, that of the object, there is the power in any degree of an outgoing act, and on the other, that of the sight, the capability of being acted upon, surely the object needs no medium through which to be effective upon what it is fully equipped to affect: this would be needing not a help but a hindrance.

Or, again, consider the Dawn: there is no need that the light first flood the air and then come to us; the event is simultaneous to both: often, in fact, we see when the light is not as yet round our eyes at all but very far off, before, that is, the air has been acted upon: here we have vision without any modified intervenient, vision before the organ has received the light with which it is to be linked.

It is difficult to reconcile with this theory the fact of seeing stars or any fire by night.

If the percipient mind or soul remains within itself and needs the light only as one might need a stick in the hand to touch something at a distance, then the perception will be a sort of tussle: the light must be conceived as something thrusting, something aimed at a mark, and similarly, the object, considered as an illuminated thing, must be conceived to be resistant; for this is the normal process in the case of contact by the agency of an intervenient.

Besides, even on this explanation, the mind must have previously been in contact with the object in the entire absence of intervenient; only if that has happened could contact through an intervenient bring knowledge, a knowledge by way of memory, and, even more emphatically, by way of reasoned comparison : but this process of memory and comparison is excluded by the theory of first knowledge through the agency of a medium.

Finally, we may be told that the impinging light is modified by the thing to be seen and so becomes able to present something perceptible before the visual organ; but this simply brings us back to the theory of an intervenient changed midway by the object, an explanation whose difficulties we have already indicated.

(2) [Now,] seeing that the hollow roundness of the Cosmos is borne round into the fashion of a sphere; by reason of its [very] quality or form, it never can be altogether visible unto itself. So that, however high a place in it thou shouldest choose for looking down below, thou could’st not see from it what is at bottom, because in many places it confronts [the senses], and so is thought to have the quality [of being visible throughout]. For it is solely owing to the forms of species, with images of which it seems insculpted, that it is thought [to be] as though ’twere visible [throughout]; but as a fact ’tis ever to itself invisible.

(7) Our investigation may be furthered by enquiring: Whether light finally perishes or simply returns to its source.

If it be a thing requiring to be caught and kept, domiciled within a recipient, we might think of it finally passing out of existence: if it be an Act not flowing out and away- but in circuit, with more of it within than is in outward progress from the luminary of which it is the Act- then it will not cease to exist as long as that centre is in being. And as the luminary moves, the light will reach new points- not in virtue of any change of course in or out or around, but simply because the act of the luminary exists and where there is no impediment is effective. Even if the distance of the sun from us were far greater than it is, the light would be continuous all that further way, as long as nothing checked or blocked it in the interval.

We distinguish two forms of activity; one is gathered within the luminary and is comparable to the life of the shining body; this is the vaster and is, as it were, the foundation or wellspring of all the act; the other lies next to the surface, the outer image of the inner content, a secondary activity though inseparable from the former. For every existent has an Act which is in its likeness: as long as the one exists, so does the other; yet while the original is stationary the activity reaches forth, in some things over a wide range, in others less far. There are weak and faint activities, and there are some, even, that do not appear; but there are also things whose activities are great and far-going; in the case of these the activity must be thought of as being lodged, both in the active and powerful source and in the point at which it settles. This may be observed in the case of an animal's eyes where the pupils gleam: they have a light which shows outside the orbs. Again there are living things which have an inner fire that in darkness shines out when they expand themselves and ceases to ray outward when they contract: the fire has not perished; it is a mere matter of it being rayed out or not.

But has the light gone inward?

No: it is simply no longer on the outside because the fire is no longer outward going but has withdrawn towards the centre.

But surely the light has gone inward too?

No: only the fire, and when that goes inward the surface consists only of the non-luminous body; the fire can no longer act towards the outer.

The light, then, raying from bodies is an outgoing activity of a luminous body; the light within luminous bodies- understand; such as are primarily luminous- is the essential being embraced under the idea of that body. When such a body is brought into association with Matter, its activity produces colour: when there is no such association, it does not give colour- it gives merely an incipient on which colour might be formed- for it belongs to another being with which it retains its link, unable to desert from it, or from its activity.

And light is incorporeal even when it is the light of a body; there is therefore no question, strictly speaking, of its withdrawal or of its being present- these terms do not apply to its modes- and its essential existence is to be an activity. As an example: the image upon a mirror may be described as an activity exercised by the reflected object upon the potential recipient: there is no outgoing from the object ; it is simply that, as long as the object stands there, the image also is visible, in the form of colour shaped to a certain pattern, and when the object is not there, the reflecting surface no longer holds what it held when the conditions were favourable.

So it is with the soul considered as the activity of another and prior soul: as long as that prior retains its place, its next, which is its activity, abides.

But what of a soul which is not an activity but the derivative of an activity- as we maintained the life-principle domiciled in the body to be- is its presence similar to that of the light caught and held in material things?

No; for in those things the colour is due to an actual intermixture of the active element ; whereas the life-principle of the body is something that holds from another soul closely present to it.

But when the body perishes- by the fact that nothing without part in soul can continue in being- when the body is perishing, no longer supported by that primal life-giving soul, or by the presence of any secondary phase of it, it is clear that the life-principle can no longer remain; but does this mean that the life perishes?

No; not even it; for it, too, is an image of that first out-shining; it is merely no longer where it was.

(8) Now: given a light of this degree, remaining in the upper sphere at its appointed station, pure light in purest place, what mode of outflow from it can be conceived possible?

Such a Kind is not so constituted as to flow downwards of its own accord; and there exists in those regions no power to force it down. Again, body in contact with soul must always be very different from body left to itself; the bodily substance of the heavens has that contact and will show that difference.

Besides, the corporeal substance nearest to the heavens would be air or fire: air has no destructive quality; fire would be powerless there since it could not enter into effective contact: in its very rush it would change before its attack could be felt; and, apart from that, it is of the lesser order, no match for what it would be opposing in those higher regions.

Again, fire acts by imparting heat: now it cannot be the source of heat to what is already hot by nature; and anything it is to destroy must as a first condition be heated by it, must be brought to a pitch of heat fatal to the nature concerned.

In sum, then, no outside body is necessary to the heavens to ensure their permanence- or to produce their circular movement, for it has never been shown that their natural path would be the straight line; on the contrary the heavens, by their nature, will either be motionless or move by circle; all other movement indicates outside compulsion. We cannot think, therefore, that the heavenly bodies stand in need of replenishment; we must not argue from earthly frames to those of the celestial system whose sustaining soul is not the same, whose space is not the same, whose conditions are not those which make restoration necessary in this realm of composite bodies always in flux: we must recognise that the changes that take place in bodies here represent a slipping-away from the being and take place at the dictate of a Principle not dwelling in the higher regions, one not powerful enough to ensure the permanence of the existences in which it is exhibited, one which in its coming into being and in its generative act is but an imitation of an antecedent Kind, and, as we have shown, cannot at every point possess the unchangeable identity of the Intellectual Realm.

(7) Locusta saith:—All those creatures which have been described by Lucas are two only, of which one is neither The Turba Philosophorum. aia 5 known nor expressed, except by piety, for it is not seen or felt.

PyTHAGoRAS saith:—Thou hast entered upon a subject which, if completed, thou wilt describe subtly. State, therefore, what is this thing which is neither felt, seen, nor known.

Then he:—lIt is that which is not known, because in this world it is discerned by reason without the clients thereof, which are sight, hearing, taste, smell, and touch. O Crowd of the Philosophers, know you not that it is only sight which can distinguish white from black, and hearing only which can discriminate between a good and bad word! Similarly, a wholesome odour cannot be separated by reason from one which is fetid, except through the sense of smell, nor can sweetness be discriminated from bitterness save by means of taste, nor smooth from rough unless by touch.

The Turba answereth:— Thou hast well spoken, yet hast thou omitted to treat of that particular thing which is not known, or described, except by reason and piety. Sazth he: —Are ye then in such haste? Know that the creature which is cognised in none of these five ways is a sublime creature, and, as such, is neither seen nor felt, but is perceived by reason alone, of which reason Nature confesses that God is a partaker. They answer:—Thou hast spoken truly and excellently.

And he:—I will now give a further explanation. Know that Ae e this creature, that is to say, the world, hath a light, which is the Sun, and the same is more subtle than all other natures, which light is so ordered that living beings may attain to vision. But if this subtle light were removed, they would become darkened, seeing nothing, except the light of the moon, or of the stars, or of fire, all which are derived from the light of the Sun, which causes all creatures to give light.

For this God has appointed the Sun to be the light of the world, by reason of the attenuated nature of the Sun. And know that the sublime creature before mentioned has no need of the light of this Sun, because the Sun is beneath that creature, which is more subtle and more lucid. This light, which is more lucid than the light of the Sun, they have taken from the light of God, which is more subtle than their light. Know also that the created world is composed of two dense things and two rare things, but nothing of the dense is in the sublime creature. Consequently the Sun is rarer than all inferior creatures.

The Turba answereth:—Thou hast excellently described what thou hast related. And if, good Master, thou shalt utter anything whereby our hearts may be vivified, which now are mortified by folly, thou wilt confer upon us a great boon!*

(1) We undertook to discuss the question whether sight is possible in the absence of any intervening medium, such as air or some other form of what is known as transparent body: this is the time and place.

It has been explained that seeing and all sense-perception can occur only through the medium of some bodily substance, since in the absence of body the soul is utterly absorbed in the Intellectual Sphere. Sense-perception being the gripping not of the Intellectual but of the sensible alone, the soul, if it is to form any relationship of knowledge, or of impression, with objects of sense, must be brought in some kind of contact with them by means of whatever may bridge the gap.

The knowledge, then, is realized by means of bodily organs: through these, which are almost of one growth with it, being at least its continuations, it comes into something like unity with the alien, since this mutual approach brings about a certain degree of identity .

Admitting, then, that some contact with an object is necessary for knowing it, the question of a medium falls to the ground in the case of things identified by any form of touch; but in the case of sight- we leave hearing over for the present- we are still in doubt; is there need of some bodily substance between the eye and the illumined object?

No: such an intervening material may be a favouring circumstance, but essentially it adds nothing to seeing power. ! Dense bodies, such as clay, actually prevent sight; the less material the intervening substance is, the more clearly we see; the intervening substance, then, is a hindrance, or, if not that, at least not a help.

It will be objected that vision implies that whatever intervenes between seen and seer must first experience the object and be, as it were, shaped to it; we will be reminded that anyone facing to the object from the side opposite to ourselves sees it equally; we will be asked to deduce that if all the space intervening between seen and seer did not carry the impression of the object we could not receive it.

But all the need is met when the impression reaches that which is adapted to receive it; there is no need for the intervening space to be impressed. If it is, the impression will be of quite another order: the rod between the fisher's hand and the torpedo fish is not affected in the same way as the hand that feels the shock. And yet there too, if rod and line did not intervene, the hand would not be affected- though even that may be questioned, since after all the fisherman, we are told, is numbed if the torpedo merely lies in his net.

The whole matter seems to bring us back to that sympathy of which we have treated. If a certain thing is of a nature to be sympathetically affected by another in virtue of some similitude between them, then anything intervening, not sharing in that similitude, will not be affected, or at least not similarly. If this be so, anything naturally disposed to be affected will take the impression more vividly in the absence of intervening substance, even of some substance capable, itself, of being affected.

(3) Since, however, a contrary is receptive of a contrary, according to a mutation and departure from itself, and that which is allied to another thing, and familiar with it through similitude, is capable of receiving it, hence the illuminators receive darkness as a cooperator, and employ in illuminating the light of the sun, or of the moon, or, in short, of the air. Sometimes, likewise, they use collocations of such things as are adapted to the Gods that are about to descend, or they employ incantations or compositions, and these appropriately prepared for the reception, presence, and manifestation of the Gods. And again, sometimes they introduce light through water, because this being diaphanous, is aptly disposed to the reception of light. But at other times, they cause light to shine forth on a wall, having previously prepared the wall for the reception of light in the best manner by the sacred descriptions of characters; and, at the same time, they fix the light in a certain solid place, so that it may not be widely diffused.