Tetrabiblos (The Quadripartite Book)

...sometimes fell. Many such astrologers, like Albumasar and many others. But you will understand if you know anything of arithmetic that this is a great error. I, indeed, studied to seek out the common number, that with this number being known, I might calculate with which you could set tables, from which all known things would emerge; and that I could not find.

These are also occasions through which we are deceived in the prognostication of judgments: because the exemplars through which we learn are not assimilated to those by which we judge.

And because of this reason, error happens sometimes in other things which ought to be because the things of which the ancient sages gave us an example cannot return to those same things without some diversity, little or much.

I say that these words are apt and do not need a gloss.

For when we investigate the accidents of the air, for this reason they are difficult to find for us, because the discovery of the occasions which are in the air is difficult, and if we discover those which were through celestial causes.

Nevertheless, the reason because of which it is difficult to understand for investigating the accidents which arise in the air is: because such an appearance of the air with such a constellation does not happen as it was another time.

Here Ptolemy teaches us how matter is not stable or firm, and teaches us that we ought to prove in this way how it places itself always in diverse modes. I begin, indeed, from that which happens in the air, because the thing is more general, because in the air many things happen, because the operation of the superior bodies is not received in every place in one manner. For in some place there will be mountains in which winds thrive because of their altitude, and because of this that air will not be able to have such great heat, or because of the fumosities which will be elevated from the humidities of some city, or because of the stench of dead bodies; for those are things that are destroyers of the air, and similar things which occur. It befits the astrologer, therefore, that he should look into the state of the air before he pronounces a judgment.

When we speak upon the nativities of men, according to the collections of the powers of many things and not frivolous, we take in this the occasions which even by themselves compel things to vary.

In speaking also in nativities which are of this proposition of powers, in every thing we find in them reasons not few, nor less than others by which they change their properties.

He says that in nativities, similarly, many things happen disturbing them so that they do not receive all the light of the stars as it was coming to them to receive.

For he speaks of seeds, of the qualities of mutations that help much. Because though any region and the air of one and the same region may be of one mode, yet the difference of seeds, for the forming of the image appropriate to its species, obtains powers, such as the seed of man and horse and the rest of the beasts.

This is because the manner of the sperm gives great aid in the properties of the generation, because the air surrounds the regions which have a determined horizon. If both shall have been of one state, any manner of sperm will come for a unique figure forming the general shape coming to any species. Just as is the sperm of man and horse and all other animals.

He wishes to say that all things which are by essence and nature live in all things. Because that which is by essence cannot be changed or moved from its nature. Wherefore the power which is in the sperm by essence is to make the shape coming only to the species of which it is; and from the sperm of a man, a shape cannot be made unless of a man, and from that of a horse, a shape cannot be made unless of a horse, and so of other animals. And similarly of the seeds of vegetables, and all other natural things, because each one of them receives, otherwise it respects the shape of their natural [state] which is to the whole same, but the accidents which happen to the sperm of any body of that species do not happen to the sperm by essence, but happen because of the formation according to the virtues of the stars in the region of the horizon, that where it was, and according to the state of the air and of that place.

The places of birth also change things by mutation.

And the places of generation change the things which are generated in them by no small mutation.

He wishes to say that in the places in which generation will be made, such as the lands of black men, all who will be generated in them will have to return to the generation of them gradually, namely to the color of the land of black men; because that which was of white, if a black man is generated much in a very cold land where there are white men, they will have to return to that generation of others gradually. And so it happens in similar ones of the same. And since it is so, it is manifest that heat is gradually removed from the sperm, nor does there remain in it except that which it has by essence and nature. And this is the power of generation only. It befits us to look to the generation of whom he is born, and to the sperm from which it descends, and to the place in which he was born; and afterwards we will be able to judge. For this is explained more in that which follows.

For when the seeds of one species shall be different, as the seed of men, and the qualities of the air also shall be the same, the born will receive many and great different qualities in body and soul according to the differences of the regions in which they are born.

And because the manner of the sperm of that generation will be of one mode, such as the sperm of a man, and the state of the surrounding air shall be of the same manner, differences of great magnitude in bodies and sperms will happen to the born according to the diversity of the regions in which they are born.

For example, he who is born in the east will be different in body and spirit from him who is born in the west, although the constellation of both nativities is one. And this is because of the accidents pertaining to any region which are formed with the sperm of any. But in other natural things you will find this same thing.

To you also, and mores, their individual future alterations will help to either.

Furthermore, since these foods and mores which they use, if they shall not be diverse, will help from one part.

This, however, you will see visibly, if you look into the mores of men and the foods which they use; because in those who use choleric foods, choler is made, and they are drawn toward those of the melancholics, and in the other complexions the same thing. And therefore, mores occur, because those who dwell and lead life with good [men], although he be bad by nature, is drawn toward the good of them; and the contrary is true of the reverse. For all this, and the reason because of which it is, you will find openly in the books of the ancient sages.

But since all things by no means agree with the occasions which arrange themselves in the air, although the force of the air which is in the being of these things according to what they are is great, it is a great occasion of help if those who predict only through the motions of the superior [bodies] are not helped by them; and those who through them only investigate that which they cannot perfectly know, sometimes are deceived.

And if all those things coming through the surrounding air have not arranged themselves, because the power of the air is very great—although the air gives great force and very great aid so that the things themselves are as they are—and these things have not helped the air, doubt and error will happen to whoever wishes to indicate only through the mode of the superior bodies, and it would be a man who wishes to know things which cannot be known perfectly by themselves.