只要稍加思考，所有人都能輕易明白：有一種源自永恆「以太」（ethereal substance）物質的力量，發散並滲透到地球周圍整個不斷發生變化的區域之中；因為在月下的基本元素中，火與空氣被以太的運動所包圍並隨之改變，進而又包圍並改變了其他一切事物——包含土、水，以及其中的動植物。
A very few considerations would make it apparent to all that a certain power emanating from the eternal ethereal substance is dispersed through and permeates the whole region about the earth, which throughout is subject to change, since, of the primary sublunar elements, fire and air are encompassed and changed by the motions in the ether, and in turn encompass and change all else, earth and water and the plants and animals therein.
因為太陽連同其周圍的環境（ambient），總是透過某種方式影響著地球上的一切：它不僅藉由伴隨四季更迭的變化，促成動物的繁衍、植物的結實、水流的運作以及物體的改變；同時也透過其每日的運行，規律地帶來熱、濕、乾與冷，而這些都與它相對於天頂的位置相呼應。同樣地，月亮作為最靠近地球的天體，將其流溢出的力量最為豐盛地賜予世間萬物；因為地球上的大多數事物，無論是有生命或無生命的，都與她產生共鳴並隨她一同變化：河川的水量隨著她的光芒增減，海洋的潮汐隨著她的升落而起伏，動植物的全部或部分也隨著她一同盈虧。
For the sun, together with the ambient, is always in some way affecting everything on the earth, not only by the changes that accompany the seasons of the year to bring about the generation of animals, the productiveness of plants, the flowing of waters, and the changes of bodies, but also by its daily revolutions furnishing heat, moisture, dryness, and cold in regular order and in correspondence with its positions relative to the zenith. The moon, too, as the heavenly body nearest the earth, bestows her effluence most abundantly upon mundane things, for most of them, animate or inanimate, are sympathetic to her and change in company with her; the rivers increase and diminish their streams with her light, the seas turn their own tides with her rising and setting, and plants and animals in whole or in some part wax and wane with her.
此外，恆星與行星在天空中的運行軌跡，通常預示著空氣中炎熱、多風與降雪的狀態，世間萬物也因此受到相應的影響。再者，它們（星體）彼此之間的相位，藉由其所釋放力量的相遇與交融，帶來了許多複雜的變化。儘管太陽的力量在主導整體特質的運作上佔有優勢，但其他天體在特定細節上會協助或阻礙它：月亮的影響更為明顯且持續（例如在新月、弦月或滿月時），而星辰的影響則間隔較長且較為隱晦（例如在它們出現、掩星或相互靠近時）。
Moreover, the passages of the fixed stars and the planets through the sky often signify hot, windy, and snowy conditions of the air, and mundane things are affected accordingly. Then, too, their aspects to one another, by the meeting and mingling of their dispensations, bring about many complicated changes. For though the sun’s power prevails in the general ordering of quality, the other heavenly bodies aid or oppose it in particular details, the moon more obviously and continuously, as for example when it is new, at quarter, or full, and the stars at greater intervals and more obscurely, as in their appearances, occultations, and approaches.
如果我們這樣看待這些現象，所有人皆能推斷出：不僅已經成形的複合事物必定會以某種方式受到這些天體運動的影響，就連種子的發芽與結果，也必然會受到當時天體特有性質的形塑與順應。事實上，那些較具觀察力的農夫與牧人，能從受孕和播種時盛行的風向，推測出最終產物的品質；一般而言我們也發現，由太陽、月亮與星辰較明顯的排列型態所預示的重大結果，通常甚至能被那些不依賴科學方法、僅憑觀察來探究的人所預知。
If these matters be so regarded, all would judge it to follow that not only must things already compounded be affected in some way by the motion of these heavenly bodies, but likewise the germination and fruition of the seed must be moulded and conformed to the quality proper to the heavens at the time. The more observant farmers and herdsmen, indeed, conjecture, from the winds prevailing at the time of impregnation and of the sowing of the seed, the quality of what will result; and in general we see that the more important consequences signified by the more obvious configurations of sun, moon, and stars are usually known beforehand, even by those who inquire, not by scientific means, but only by observation.
那些肇因於更強大力量與更單純自然規律的事件（例如季節與風的年度變化），即使是極其無知的人，甚至是一些無法言語的動物也能理解；因為這些現象主要是由太陽所主導。然而，那些不具備如此普遍性質的事物，則是由出於需要而習慣進行觀察的人來理解。例如，水手們知道因月亮和恆星與太陽的相位而週期性產生的暴風雨和風勢的特殊前兆。但由於他們知識有限，無法準確知道這些現象發生的時間與地點，也無法掌握對這些影響有著重要作用的行星週期性運動，因此他們經常會發生失誤。
Those which are consequent upon greater forces and simpler natural orders, such as the annual variations of the seasons and the winds, are comprehended by very ignorant men, nay even by some dumb animals; for the sun is in general responsible for these phenomena. Things that are not of so general a nature, however, are comprehended by those who have by necessity become used to making observations, as, for instance, sailors know the special signs of storms and winds that arise periodically by reason of the aspects of the moon and fixed stars to the sun. Yet because they cannot in their ignorance accurately know the times and places of these phenomena, nor the periodic movements of the planets, which contribute importantly to the effect, it happens that they often err.
那麼，如果一個人能準確知曉所有星辰、太陽與月亮的運動，使得它們任何排列型態發生的地點與時間都逃不過他的注意；如果他藉由過去持續的研究，已大致區分出它們的性質——即使他辨識出的並非它們的本質，而僅是其潛在的效用特質（例如太陽發熱、月亮致濕，其餘星體亦然）；如果他能夠基於所有這些數據，透過科學方法與精確的推測，推斷出由所有因素結合而成的獨特品質特徵： 那麼，有什麼能阻止他根據當時各種現象的關聯性，在每一個特定場合判斷出空氣的特徵（例如天氣會變暖或變濕）呢？
If, then, a man knows accurately the movements of all the stars, the sun, and the moon, so that neither the place nor the time of any of their configurations escapes his notice, and if he has distinguished in general their natures as the result of previous continued study, even though he may discern, not their essential, but only their potentially effective qualities, such as the sun’s heating and the moon’s moistening, and so on with the rest; and if he is capable of determining in view of all these data, both scientifically and by successful conjecture, the distinctive mark of quality resulting from the combination of all the factors, what is to prevent him from being able to tell on each given occasion the characteristics of the air from the relations of the phenomena at the time, for instance, that it will be warmer or wetter?
同樣地，對於一個特定的人，他為何不能從其出生時的周遭環境（天體運行狀態）中，洞察其性情的整體特質——例如他在身體上會是如何、在靈魂上又會是如何——並利用「某種環境與某種性情相協調且有利於繁榮，而另一種環境則不協調並會導致傷害」的這項事實，來預測偶然發生的事件呢？不過，這已經說得夠多了；因為透過上述這些及類似的論點，已足以讓人理解這類知識（占星預測）的可能性。
Why can he not, too, with respect to an individual man, perceive the general quality of his temperament from the ambient at the time of his birth, as for instance that he is such and such in body and such and such in soul, and predict occasional events, by use of the fact that such and such an ambient is attuned to such and such a temperament and is favourable to prosperity, while another is not so attuned and conduces to injury? Enough, however; for the possibility of such knowledge can be understood from these and similar arguments.
The following considerations might lead us to observe that criticism of the science on the score of impossibility has been specious but undeserved. in the first place, the mistakes of those who are not accurately instructed in its practice, and they are many, as one would expect in an important and many-sided art, have brought about the belief that even its true predictions depend upon chance, which is incorrect. For a thing like this is an impotence, not of the science, but of those who practise it. Secondly, most, for the sake of gain, claim credence for another art in the name of this and deceive the vulgar, because they are reputed to foretell many things, even those that cannot naturally be known beforehand, while to the more thoughtful they have thereby given occasion to pass equally unfavourable judgement upon the natural subjects of prophecy. Nor is this deservedly done; it is the same with philosophy — we need not abolish it because there are evident rascals among those that pretend to it. Nevertheless it is clear that even though one approach astrology in the most inquiring and legitimate spirit possible, he may frequently err, not for any of the reasons stated, but because of the very nature of the thing and his own weakness in comparison with the magnitude of his profession. For in general, besides the fact that every science that deals with the quality of its subject-matter is conjectural and not to be absolutely affirmed, particularly one which is composed of many unlike elements, it is furthermore true that the ancient configurations of the planets, upon the basis of which we attach to similar aspects of our own day the effects observed by the ancients in theirs, can be more or less similar to the modern aspects, and that, too, at long intervals, but not identical, since the exact return of all the heavenly bodies and the earth to the same positions, unless one holds vain opinions of his ability to comprehend and know the incomprehensible, either takes place not at all or at least not in the period of time that falls within the experience of man; so that for this reason predictions sometimes fail, because of the disparity of the examples on which they are based. As to the investigation of atmospheric phenomena, this would be the only difficulty, since no other cause besides the movement of the heavenly bodies is taken into consideration. But in an inquiry concerning nativities and individual temperaments in general, one can see that there are circumstances of no small importance and of no trifling character, which join to cause the special qualities of those who are born. For differences of seed exert a very great influence on the special traits of the genus, since, if the ambient and the horizon are the same, each seed prevails to express in general its own form, for example, man, horse, and so forth; and the places of birth bring about no small variation in what is produced. For if the seed is generically the same, human for example, and the condition of the ambient the same, those who are born differ much, both in body and soul, with the difference of countries. In addition to this, all aforesaid conditions being equal, rearing and customs contribute to influence the particular way in which a life is lived. Unless each one of these things is examined together with the causes that are derived from the ambient, although this latter be conceded to exercise the greatest influence (for the ambient is one of the causes for these things being what they are, while they in turn have no influence upon it), they can cause much difficulty for those who believe that in such cases 9everything can be understood, even things not wholly within its jurisdiction, from the motion of the heavenly bodies alone.
Since this is the case, it would not be fitting to dismiss all prognostication of this character because it can sometimes be mistaken, for we do not discredit the art of the pilot for its many errors; but as when the claims are great, so also when they are divine, we should welcome what is possible and think it enough. Nor, further, should we gropingly and in human fashion demand everything of the art, but rather join in the appreciation of its beauty, even in instances wherein it could not provide the full answer; and as we do not find fault with the physicians, when they examine a person, for speaking both about the sickness itself and about the patient’s idiosyncrasy, so too in this case we should not object to astrologers using as a basis for calculation nationality, country, and rearing, or any other already existing accidental qualities.