First Part
Light defined with the Principles1. Light is a good being that naturally does good in its own way, and its own Goodness is its natural reason to do good: now candlelight is a good being that naturally does its own kind of good by lighting lamps and lighting up the air; the Sun illuminates the atmosphere to cause daylight, and daylight is a good thing because it is instrumental in destroying darkness and enabling animals to see; likewise, the Moon shines at night to dispel the darkness that does evil against good when it hinders the sight from seeing.
2. Light is a great being on account of its own natural Greatness with which it produces great Illumination; candlelight, for instance, does its great act by illuminating lamps and air. And light has a great act potentially existing in its own great, natural and coessential Greatness: now if candlelight had enough fuel, it would grow into a flame so huge that it would light up the entire sphere of air and consume all darkness and shadow.
3. Light is a being that lasts in its own natural Duration with which it causes the Goodness, Greatness, Power, Instinct, Appetite and Virtue of light to last in air, so much so that if light never ran out of matter, it would last forever without decreasing in quantity: if candlelight never ran out of wick and wax, it could effectively last forever.
4. Light is a powerful being by its very nature: its innate Power enables it to maintain its size and identity and to produce other light or lights without decreasing or going out, as when candlelight lights a lamp without decreasing or vanishing: this is because its own Goodness, Greatness etc. sustain its identity, and they cannot do this if the light runs out of material, namely its wick and its wax, or if the wind blows it out, or if it is placed where it cannot move, given that light enclosed on all sides in a small space cannot move.
5. Light is a being with a natural Instinct for doing things proper to its own nature, for instance, the light of a candle has an Instinct for lighting a lamp by using all of its own active mode and the lamp's entire passive mode: candlelight cannot light a lamp without the entirety of its mode because its Instinct cannot perform without a mode just as the intellect cannot understand things unless it has a mode for understanding them.
6. Light is a being with its own natural Appetite for illuminating things and reproducing its likenesses, and its Appetite reposes in the act of illuminating, as when a candle lights a lamp and lights up the air and when it extends its flame down to another, extinguished candle to which it is drawn through the smoke by its appetite for lighting things, as we know by experience. And likewise, the intellect reproduces the likenesses it acquires to make them intelligible and exercise the natural acts of its own Goodness, Greatness etc. in its own understanding of itself.
7. Light is a being that arises with its own Virtue from a flame, and as it is infused in the air or in a lamp, it optimizes its virtuous Goodness and magnifies its virtuous Greatness, as when the Virtue of candlelight lights up air and lights lamps with its own Virtue.
8. Light is a being that truly illuminates air and lamps with itself, from itself, from its own Goodness, Greatness etc. and with its own Goodness, Greatness etc. while Truth makes this a true visual experience; and the intellect, likewise, in its own way, truly enlightens scholars with the science it teaches when its matter and the scholar's matter are not impeded by ignorance.
9. Light is a being that delights in existing and acting: in existing because it is what it is and in acting because it reproduces itself, like candlelight that has natural delight in lighting up lamps and space. And likewise, the light of intellect delights in understanding and reproducing its likenesses in itself and in the humans who use it to learn science; in this way, when the intellect is joined to a body, it delights in attracting to itself the things it can reach through the senses and the imagination, and it delights in making all this intelligible within itself so it can have repose.
10. Light is a being that lights up colors and shapes and enables the power of sight to see colored objects: as the intellect attains the truth about things by telling them apart, likewise, light disposes distinct colors and figures in the physically visible world, now if there is no light, the power of sight cannot perform its act of seeing.
11. Light is a being that accords visibility to visible subjects so that the power of sight can objectify things and attain one light through its concordance with another light: now candlelight and lamplight both belong to the same genus as they light up a house; and so do sunlight and firelight because the Sun effectively increases the heat of fire as the Sun convenes with fire in the genus of light and heats bodies here below with the heat of fire.
12. Light, or brightness, is the color of fire and of the Sun, and darkness cannot resist this color unless some opaque body impedes it; this is because darkness and shadow are the colors of earth which air receives in its great transparency, taking on these colors wherever light is partly blocked out as when a crystal placed on green, blue or red colors receives and takes on these colors; now transparency is the color of air, fire and air agree in heat while light drives out and dispels darkness and lends its color to air as we see when the Sun shines by day and when candles illuminate courtyards at night.
13. Light is the supreme source of color because the luminaries of heaven convene with the light of fire in the same genus; now the colors of the luminaries in heaven are not in the same genus as the colors of earth, water or air.
14. Light is the form used by fire to move lightable matter that is lit whenever form and matter repose in light.
15. Light is a being that quantifies things with its quantity, and it has two kinds of quantity, namely continuous and discrete. It is continuous, for instance, in the various sources of light in a house, or in sunlight by day and moonlight at night; and it is discrete in Saturn and Jupiter etc. in heaven and in the Sun by day and in the Moon at night, and in a lamp in a room and in a candle in a courtyard.
16. Light is a being with the quality of showing things and it shows that the subject of brightness consists of its innate bright parts and this subject lends brightness to other subjects that do not shine by themselves, as the Sun illuminates the Moon and candlelight lights up the air, lamps, etc.
17. Light is a being that relates to things by showing them and it shows that sunlight - or the Sun's body - and fire both have substantial, coessential, innate related parts namely the lucificative, lucificable and their act of lucification that give rise to accidental, peregrine light when light illuminates and colors the air.
18. Light is a being that acts by illuminating air and coloring and brightening it with light, and its action overcomes darkness as was shown above.
19. Light is a passive form whose matter is the general illuminability in which peregrine luminaries receive light. And light is a passive form or power when opaque bodies stop it from dispelling darkness and from growing and expanding in quantity and movement.
20. Light is a habit of air illuminated by the Sun in daytime or by a candle in a room and thus light is a being situated in the subject in which it exists, namely in the air's length, breadth and depth, in the Sun's and Moon's roundness, in the triangular shape of flames, in potentiality in a covered lamp and in motion when a stone is struck with iron.
21. Light is a being that produces times and seasons and participates in motion more closely than any other being; now light cannot be without motion, and since motion accords with time, light participates in sequential motion more closely than any other being does.
22. Light is a being that locates itself in the air that it lights up and that locates air within itself in every place to which its radiance extends. And here we see how one color is contained in another; and as every proper color is inseparable from its own subject, we see how bodies in mixture stand within one another as when elements mix together in elemented things, or when gold and silver are mixed in coins, or when substance and accident are mixed in compounds.
23. Light is a being that habituates the things it illuminates: as when candlelight habituates and clothes illuminated air by coloring it with its light, or when it clothes a rose with light shining through the air; and likewise the intellect habituates itself with science in its own innate intelligibility by acquiring peregrine species habituated with intelligibility.
24. Light is a subject that exists in space within a horizon in which the color of air is joined to the color of fire, by the Sun in daylight and by the Moon at night, and by a candle flame in a room where continuous and undivided light shines on every extreme of every wall as candlelight lights up the air and as the air lets light shine through its transparency, which cannot happen unless the light and the air mix together to make one compound that occupies the entire space within the horizon both formally and materially.
25. Light is the end in which the colors of fire and air repose as does the power of sight which cannot see anything without light: they repose when their appetite is joined to the desired object, as when the lover is joined to the beloved and when the knower is joined to knowledge, which comes about in an act of illumination, when the act of loving joins the lover to the beloved and the act of knowing joins the knower to the knowledge.
26. Light is an image of God's immense Magnitude, Goodness, Eternity, Power, Wisdom, Will, Virtue, Truth and Glory; now if a lit candle had an infinite amount of fuel placed at its disposal, it could, with its act of illuminating, make its lucificative luminance shine out into infinity; but since candlelight cannot do this for lack of fuel and space, this power of light only exists potentially, as does the light of human intellect, memory and will. And here we see the Greatness of God the creator displaying the outward signs of his intrinsic operation and Trinity.
27. Light is a subject in which the final concordance between the illuminative and illuminated equally reposes in their act of illuminating; and the same is understood about the light of intellect and the flame of love in the knower, knowledge and act of knowing and in the lover, beloved and act of loving; here we see how spiritual things are signified by corporeal ones.
28. Light is a being whose minority makes it exist in proximity to nothingness; and it really has minority because it is deprived of being when it is deprived of material and when its opposite, namely darkness comes into being. Light also exists in minority and close to naught when it potentially exists in a stone without the presence of external agents, like motion and a collision with iron or with another stone without which it cannot manifest its act.
We used definitions to show how the general Principles apply to light, and as we applied them to light, they can be applied to different beings in different ways.