Tetrabiblos (The Quadripartite Book)

For it is appropriate for us to know future things: because unless we had known them beforehand and prepared for them, we might at the hour find such a thing that would cause us to lose our senses, or an hour might supervene, or such joy or sadness that would cause the same.

We see this visibly every day. And we know of men who found treasure at a sudden hour without foreknowledge, from which they lost their senses from excessive joy which they could never recover; but they were ruined by this. And [we know] of others to whom an hour supervened from which they were so terrified that they lost their senses from excessive fear; yet he who is able to know future things beforehand will not lose his senses, but will remain firm in his memory. For this is the profit of the good, concerning those things from which he cannot be liberated in any way on account of the constellation demonstrating this, which is very strong. But if it is otherwise, so that by some preparation he might have strength, his profit is much greater.

Prognostication truly applies and draws the soul to frequent memories of things yet far off, so that it holds them as if they were constant and present; and it adapts the soul plainly and pleasantly to the reception of any future thing whatsoever.

Prognostication nevertheless changes the use of the spirit, gradually bringing into the mind those things which are to be far in the future, and hastens them to itself as if they were present, very mildly and without violence.

When a man knows a future thing which in no way can be avoided, he brings it into his mind more often and tempers himself in it, and it does not supervene impetuously, just as with death, for which he prepares himself every day. Similarly, when someone knows beforehand and will find or gain something when the time is known, he will think about it spaciously, how he might guard it or by what way he might have it more quickly. Whence when you hope well in such matters, you will find it, as Ptolemy said. And since such great profit lies in knowing those things which are to be before they are, for the sake of soothing the will and the senses in those things from which a man cannot be liberated, it is all the more so that if he could be liberated by some preparation, the statement of those who said that knowing prognostications is not profitable is not true.

Again, it is not to be thought that the superior [bodies] proceed over their significations inevitably, just as those things which happen by divine disposition, which are in no way to be avoided and which truly and by necessity come to pass.

And because of this, it is not proper that we think that all things which happen to men through the celestial bodies are necessary, like divine things which a man cannot remove.

Because he said "through celestial bodies," he wishes to say "on account of the commixtures which occur in the air surrounding us, due to the figures of the courses of the stars." But the difference that is between a divine thing and another is this: that a thing of the world cannot disturb that which comes from God, and so no one can be liberated [from it]; but other things are not so. Ptolemy, however, says this for this saying, that we should not believe that all the works of the stars are always necessary like divine things; yet there are those which are such and those which can be changed, and so a man can be liberated. And since it is so, it is manifest that when we have known the things which can be changed, by which we shall be able to guard ourselves by some other preparation, then the profit of this art will be great and manifold.

Moreover, we ought to know that the powers of the celestial bodies are by divine disposition, which cannot be prohibited, because they come to pass truly; and also that the variation of terrestrial things proceeds by a natural path, which varies as they receive the occasions of superior things accidentally; and that some things occur to men also by a general calamity, not from the property of any thing,

as in a great change of the air. It will be that many of the things that happen to men, which occur from excess of air or mortality or drowning, we can guard against. These things, however, happen because a great and strong occasion overcomes the short and weak spirit-occasion; and that some of the accidents happen according to the natural and proper complexion of each one, by the change of those things contrary to it.

Moreover, it behooves us to know that the motion of the celestial bodies is a divine thing which a thing of the world cannot disturb in any way, since it is necessary and thus cannot be otherwise; but the changes of terrestrial things are natural and convertible, receiving their own things from the celestial bodies in the manner of an accident and that which follows it. And one part of the accidents happening to men proceeds on account of general and universal pestilences, and does not happen from the proper nature which each thing has by itself. As happens when the air is corrupted, a corruption so great that men can barely guard themselves so that many of them do not die; either because of their great heat, or because of the air, or putrefaction, or because of evil winds which cause many to perish in the sea, because always the greater and stronger overcomes the weaker and smaller. Accidents, however, are some things contingent upon the natural and proper complexion of each one, because of some change of contrary mutations.

This whole thing is one aphorism and its gloss is in this manner: the motion of the stars and the virtues which are joined from their motions inwardly are necessary things. And regarding the second [part]: which nothing can disturb, nor is it a thing that can be changed or averted in any manner or way. Yet, insofar as terrestrial things receive the works of their virtues, it is a natural and convertible thing, because these terrestrial things are subjects by themselves and receive the works of the celestial bodies in the manner of an accident and a consequential way, just as a diminished thing more receives the works of perfection, as a transparent thing receives light, according to the power toward the transparent which is completed. These words, however, demonstrate the great power of Ptolemy in knowing divine and natural things; and all his words aptly demonstrate great wisdom and his ability in speaking in all parts of the subject. And that which he said, that some accidents happen to men on account of more general and universal pestilences and not from the proper nature which each thing has, he wishes to say that each of the natural things receives in its beginning, from the virtue of the stars, its own property in all its mutations. And when it happens through the stars a thing more general and of greater virtue than that which pertains to any one of the particular things, that more general [thing] and [that] of greater virtue destroys particular accidents, and it has the power to change all works; thus it happens in times when the air that surrounds us is changed by such a change that one can barely guard oneself from it, because where many people die, or where great floodings of water cause mortality in places, or as happens in great wars in which many perish. And Ptolemy, in such things as these, gives a reason which is that the greater body conquers the smaller, and the stronger [conquers] the weaker. And he said that the accidents pertaining to each thing, according to what they receive by the nature of the hour in which they are generated by the celestial bodies, are also changed by their own [nature]. And since it is so, it is manifest that all terrestrial things do not receive the works of the stars in such a way that they cannot be changed. Yet there are such among them that can be changed, and in such things the knowledge of prognostications is of very great profit.