Tetrabiblos and Centiloquy

...because different qualities are assigned to those being born according to the differences of the regions in which they are born. Their upbringing and diverse customs will also assist, in whatever way, their future individual inclinations. But since all things do not always agree with the conditions that have harmonized in the air—although the power of the air is great in the existence of these things—the occasion of great assistance is lost if those who predict solely through the movements of the heavenly bodies do not take these factors into account. And by investigating through those movements alone, that which they cannot know perfectly, they will sometimes be deceived. Since this is so, it is not because we are sometimes deceived in it that this whole science should be despised and destroyed; just as the skill of sailors, who frequently err while navigating, is neither despised nor rejected by us, but rather we ought to remain more attentive and solicitous in it. For they promise us arduous and inestimable things; and let us not doubt that which is possible to attend to through it. Likewise, it is not fitting that we investigate all things through it, but only by investigating [what is appropriate]. For we say it is necessary that we grasp the materials of these things, nor should we judge it unsuitable; for just as we do not reprimand doctors when they seek the causes of illnesses and the qualities of the sick, so it should not be troublesome to us to investigate materials and regions, and foods, and all things which are past accidents In this context, "accidents" refers to the Aristotelian concept of non-essential properties or external circumstances affecting a person..

¶ Chapter 3. To demonstrate the utility of this work.

How the prognostications of the stars are understood: and that through them only those accidents which surround the globe of the earth, and which happen to men by the occasion of these things, become known; and how through these, the accidents of men pertaining to their body and soul, and their powers, as well as the works they have performed from their first to their final years, are relevant. And those things which happen from without, which adhere to the aforesaid naturally and inevitably, he wishes [to show] by a certain connection of love which exists between the body and the substance, as well as its companion—

—and as the connection which exists between the soul and its progeny; and whatever dominion among them happens in certain hours: it has been generally proven. Now, however, we shall indicate the remainder of the premises: which is to briefly investigate the utility of this work. But we have first proposed to explain the manner and intention of knowing the quantities of the fruit of this science. For we shall say that if we wish to consider the quantity of this utility which pertains to the soul, we shall find there is nothing from which the alacrity Note and improvement of the soul may assume so much. And we say universally that there is nothing in which the soul profits so much as in the prognostication of this science. For through it we arrive at the knowledge of divine and human things. Likewise, there is utility for the body, since we cannot arrive at those things which are suitable for each temperament original: "complexioni" - referring to the four humors/temperaments. except through the knowledge of this work. Regarding riches and dignities and similar things, we can say that which we consider in all philosophy. For it is not the nature of philosophy of itself to lead to any gain of the aforesaid, nor is it so unsuitable as to be blamed by men. Similarly, therefore, this science is not to be blamed because of this occasion, nor are its great utilities to be postponed. Generally also, the reasons of those blaming this science and saying it is of no utility, will be clear to those paying attention that they have not spoken truly. For their foolish deliberation was inclined to this: that they said prognostications of things happening inevitably were superfluous and useless. To this, their words are dissolved, lacking subtle insight and suitable knowledge. For first we ought to know that necessary things, when they happen to someone, unless they are foreseen, will perhaps harm him greatly; and to such an extent that they will take away sense and memory: or they will confer so much of either joy or sadness that the same will happen. Prognostication, however, applies and draws the soul to frequent memories of things still far off, so that it holds them now as constant and as present: and plainly and gently [prepares] it...