Indeed, the lights of the other heavens differ in their light, number, and power: for the greater power of any of them is gathered in different parts. For the splendor or light of each heaven of the seven planets is visibly gathered into one body meaning the visible disk of the planet; the light or splendor of the eighth heaven the sphere of the fixed stars, however, is gathered in various places or visible bodies according to the parts assigned to them for different operations by the First Cause God. Thus, they are able to impress many and diverse meanings, just as the Prime Artisan the Creator established for them from their formation. In the impression of the ninth heaven Primum Mobile; the "first moved" sphere that carries all others, a consistency is maintained; but in the impression of the other heavens, consistency is not maintained, but rather diversity—as I shall tell you in its proper place and time. Without these heavens, generation and corruption the Aristotelian cycle of birth and decay would not occur, and the impressions of the sensible heavens are felt according to their diversity.

Even if the lower world were to receive impressions or influence from the ninth heaven that were either distinct or indistinct, it still could not flow into or impress upon lower things uniformly, but only in diverse and different ways. Nor could the ninth heaven influence or impress upon lower things except through the mediation of the sensible heavens the planets and stars we can see, whose impressions are manifest. The impressions of that ninth heaven, however, are hidden; for they cannot be manifest unless they are diversified, just as wind or water, when it enters through narrow and tight passages, possesses more power and its virtue is more apparent and more felt. It is like water that runs through a mill-race; it works more strongly and has more power than water that runs through the width or spaciousness of a riverbed.

And just as the light or splendor of the moon, when it enters through some narrow place, if it finds a horse having a sore original: "fictam", likely a fistula or saddle-gall on its back and strikes the wound of that sore, the horse is destroyed and dies from it; but if the whole horse stands in the splendor of the moon’s light, so that the whole of it is seen by the moon and covered by the splendor of its light—both the place of the sore and the other parts of the horse—it does not harm or hurt it; this is as the physicians testify.

Furthermore, one can argue against the critics in this way: for there are none who now criticize astronomy except certain ones who call themselves theologians (though they are what they are), who say that astrologers do not know the whole of astronomy. They argue that if astrologers do not know it all, they cannot judge according to it nor predict anything of the future, since the stars are almost innumerable and astrologers make mention of only 1,022 of them, besides the planets.

To this it can be answered that although the astrologer does not name all the stars because it would be too long a task, he nevertheless makes use of them all: for he uses the twelve signs the Zodiac under which all the stars are observed to be contained. And it can be said to those critics that they themselves do not know the whole of theology, yet they nevertheless preach all day long. If they can preach while knowing only a little theology, much more strongly can the astrologer judge while knowing much of astronomy. For it is impossible to know so little of astronomy that it would not be much in respect to what can be known of theology. For the First Cause God is greater in respect to the heaven than the heaven is in respect to a mustard seed; yet the astrologer knows more of the heaven than a mustard seed is in size, while they do not know as much of God as a mustard seed is in respect to the heaven. It remains, therefore, that astrologers know more of astronomy than these critics know of theology; therefore, they can judge much more effectively than those critics can preach.

For astrologers know of astronomy as much as the stars and the sensible heavens can impress and signify. Concerning that Empyrean or invisible heaven the highest heaven, the dwelling place of God, it is nothing to the astrologer, nor to his judgments, nor to the motions of the stars, nor to those things which coincide with them. For that other heaven, just as it is immobile and immutable, so it is also non-acting, since stars do not act upon these lower, corruptible things insofar as they are stars or insofar as they are super-celestial, but insofar as they possess motion and are moved.

Chapter five against those who said that the planets or other stars have nothing to signify regarding generation, nor regarding corruption, nor regarding any of these things which occur below the sphere of the moon.

Another objection comes from certain people who said that the planets or other stars have nothing to signify regarding generation, nor regarding corruption, nor regarding any of the things that occur below the sphere of the moon. To them it must be answered thus: that all the wise agree on this, that lower things are ruled by higher things. This does not mean that the stars rule men or a horse or a chariot or a ship or other corruptible instruments in the same way that men (who are corruptible) rule them; for it is not fitting for the effect to reach the dignity of its cause. Rather, they rule them by moving and altering the elements Earth, Water, Air, and Fire and converting them; from these, generation and corruption occur, and they create individuals from the elements which are eventually corrupted. Finally, the individuals are corrupted and return to the elements, and thus that which they say is annihilated.

Chapter six against those who say that the planets have significance over universal things only.

Another objection comes from certain people who say that the planets have significance only over universal things species or general categories and not particulars individuals. To them it must be answered that every individual consists of the elements, and it is necessary that they be so made, and the elements constitute that individual. Nor could the elements constitute it unless they were altered by the planets (not excluding other stars) moving themselves around those things with a continuous and tireless revolving. For if the planets signified species universally as they said, and if that were true, it would be necessary that they signify the individuals constituting the species; and not only the individuals, but the parts of the individuals, such as the hand, the foot, the head, and the like. And the planets also, through the conversion of the elements and their mutation and alteration, cause individuals to grow, increase, age, become infirm, and similar things, because of the corruption and conversion of the elements, until they are again corrupted and return to the elements.

Chapter seven against those who said that the stars signify only two things, namely the necessary and the impossible; but the possible not at all.

Another objection comes from certain people who said that the stars signify only two things: namely, the "necessary" and the "impossible," but not the "possible." The "necessary" is like fire being hot; the "impossible" is like a horse flying. But the "possible" they exclude, such as a man moving or writing. To them it can be answered thus: that some things are necessary, and some are impossible. For some things are necessary, such as the heaven revolving by its own nature; some are impossible, such as fire being cold by its own nature; and some are possible, such as water being hot by accident i.e., by being heated and not by its own nature.

And for a man to speak is possible by his nature; it is possible for a man to speak now, and that he has spoken until now, and that he may speak in the future. But although he may have spoken in two times—formerly and now—it is not however necessary that he will have spoken in the future. For what is necessary or natural to a species belongs to every individual of that species, just as flying belongs to birds, for in every individual of those species, this—namely, being able to fly—is found. That which is possible for a species is possible for every individual of that species. Thus it appears what is possible: for it is not necessary for a man to spin wool, nor is it impossible for a man to spin. Hence we see some men spinning, and others not spinning. And it is possible for this man to be a king when he is born, and it is possible for this same man not to be a king. If he was not a king, it was [still once] possible for him to be a king. But between the necessary and the impossible, the middle ground is the possible; and between the necessary...