And as for the question of the powers whose actions are studied in astrology, I can do no better than refer you to the classical text of astrology, the Tetrabiblos of Ptolemy of Alexandria (2nd century AD).
Here he is discussing the nature of those powers - and it is clear that nothing non-natural or 'superhuman' in a religious sense is involved:
THAT a certain power, derived from the æthereal nature, is diffused over and pervades the whole atmosphere of the earth, is clearly evident to all men. Fire and air, the first of the sublunary elements, are encompassed and altered by the motions of the æther. These elements in their turn encompass all inferior matter, and vary it as they themselves are varied; acting on earth and water, on plants and animals. 1
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The Sun, always acting in connection with the Ambient, contributes to the regulation of all earthly things: not only by the revolution of the seasons does he bring to perfection the embryo of animals, the buds of plants, the spring of waters, and the alteration of bodies, but by his daily progress also he operates other changes in light, heat, moisture, dryness and cold; dependent upon his situation with regard to the zenith.
The Moon, being of all the heavenly bodies the nearest to the Earth, also dispenses much influence; and things animate and inanimate sympathize and vary with her. By the changes of her illumination, rivers swell and are reduced; the tides of the sea are ruled by her risings and settings; and plants and animals are expanded or collapsed, if not entirely at least partially, as she waxes or wanes.
The stars likewise (as well the fixed stars as the planets), in performing their revolutions, 1 produce many impressions on the Ambient. They cause heats, winds, and storms, to the influence of which earthly things are conformably subjected.
And, further, the mutual configurations of all these heavenly bodies, by commingling the influence with which each is separately invested, produce a multiplicity of changes. The power of the Sun however predominates, because it is more generally distributed; the others either co-operate with his power or diminish its effect: the Moon more frequently and more plainly performs this at her conjunction, at her first and last quarter, and at her opposition: the stars act also to a similar purpose, but at longer intervals and more obscurely than the Moon; and their operation principally depends upon the mode of their visibility, their occultation and their declination.
From these premises it follows not only that all bodies, which may be already compounded, are subjected to the motion of the stars, but also that the impregnation and growth of the seeds from which all bodies proceed, are framed and moulded by the quality existing in the Ambient at the time of such impregnation and growth. And it is upon this principle that the more observant husbandmen and shepherds are accustomed, by drawing their inferences from the particular breezes which may happen at seed-time and at the impregnation of their cattle, to form predictions as to the quality of the expected produce. In short, however unlearned in the philosophy of nature, these men can foretell, solely by their previous observation, all the more general and
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usual effects which result from the plainer and more visible configurations of the Sun, Moon, and stars. It is daily seen that even most illiterate persons, with no other aid than their own experienced observation, are capable of predicting events which may be consequent on the more extended influence of the Sun and the more simple order of the Ambient, and which may not be open to variation by any complex configurations of the Moon and stars towards the Sun. There are, moreover, among the brute creation, animals who evidently form prognostication, and use this wonderful instinct at the changes of the several seasons of the year, spring, summer, autumn, and winter; and, also, at the changes of the wind.
In producing the changes of the seasons, the Sun itself is chiefly the operating and visible cause. There are, however, other events which, although they are not indicated in so simple a manner, but dependent on a slight complication of causes in the Ambient, are also foreknown by persons who have applied their observation to that end. Of this kind, are tempests and gales of wind, produced by certain aspects of the Moon, or the fixed stars, towards the Sun, according to their several courses, and the approach of which is usually foreseen by mariners. At the same time, prognostication made by persons of this class must be frequently fallacious, owing to their deficiency in science and their consequent inability to give necessary consideration to the time and place, or to the revolutions of the planets; all which circumstances, when exactly defined and understood, certainly tend towards accurate foreknowledge.
When, therefore, a thorough knowledge of the motions of the stars, and of the Sun and Moon, shall have been acquired, and when the situation of the place, the time, and all the configurations actually existing at that place and time, shall also be duly known; and such knowledge be yet further improved by an acquaintance with the natures of the heavenly bodies--not of what they are composed, but of the effective influences they possess; as, for instance, that heat is the property of the Sun, and moisture of the Moon, and that other peculiar properties respectively appertain to the rest of them;--when all these qualifications for prescience may be possessed by any individual, there seems no obstacle to deprive him of the insight, offered at once by nature and his own judgment, into the effects arising out of the quality of all the various influences compounded together. So that he will thus be competent to predict the peculiar constitution of the atmosphere in every season, as, for instance, with regard to its greater heat or moisture, or other similar qualities; all which may be foreseen by the visible position or configuration of the stars and the Moon towards the Sun.
Since it is thus clearly practicable, by an accurate knowledge of the points above enumerated, to make predictions concerning the proper quality of the seasons, there also seems no impediment to the formation of similar prognostication concerning the destiny and disposition of every human being.