Seneca seems to regard scientific research as a sort of religious exercise. His enthusiasm in the study of natural forces appears largely due to the fact that he believes them to be of a sublime and divine character, and above the petty affairs of men.
Indeed, the phenomena which he discusses are mainly meteorological manifestations, such as winds, rain, hail, snow, comets, rainbows, and—what he regards as allied subjects—earthquakes, springs and rivers. Probably he would not have regarded the study of zoölogy or of physiology as so sublime. At any rate he considers only a comparatively few “natural questions,” and hence the amount and variety of belief in magic which he has occasion to display is correspondingly limited.
It is evident enough, however, that Seneca by no means accepted magic as a whole. He tells us that uncivilized antiquity believed that rain could be brought on or driven away by incantations, but that to-day no one needs a philosopher to teach him that this is impossible.[[169]] And, although he affirms that living beings are generated in fire, believes in some rather peculiar effects of lightning, such as removing the venom from snakes which it strikes, and recounts the old stories of floating islands and of waters with power to turn white sheep black, he is sceptical about bathing in the waters of the Nile as a means of increasing the female’s capacity for child-bearing.[[170]] He qualifies by the phrases, “it is believed” and “they say,” the assertions that certain waters produce foul skin-diseases and that dew in particular, if collected in any quantity, has this evil property.[[171]] I imagine he did not believe the story he repeats that the river Alphæus of Greece reappears in Sicily as the Arethusa, and there every four years, on the very days when the victims are slaughtered at the Olympian games, casts up filth from its depths.[[172]] The themes Seneca discusses of course afford him less opportunity for the taking up of the magic properties of plants, animals and other objects, but he was probably less credulous in this respect than Pliny, unless his pretensions are even more deceptive.
Seneca did believe, however, that whatever is caused is a sign of some future event.[[173]] He accepts divination in all its ramifications. Only he holds that each flight of a bird is not caused by direct act of God nor the vitals of the victim altered under the axe by divine interference, but that all has been arranged beforehand in a fatal and causal series.[[174]] He believes that all unusual celestial phenomena are to be looked upon as prodigies and portents.[[175]] But no less truly do the planets in their unvarying courses signify the future. The stars are of divine nature and we ought to approach the discussion of them with as reverent an air as when with lowered countenance we enter the temples for worship.[[176]] Not only do the stars influence our upper atmosphere as earth’s exhalations affect the lower, but they announce what is to occur.[[177]] Seneca employs the statement of Aristotle that comets signify the coming of storms and winds and foul weather, to prove that comets are stars; and declares that a comet is a portent of a storm in the same way as the Chaldeans say that a star brings good or ill fate to men at birth.[[178]] In fact, his chief, if not sole, objection to the Chaldeans would seem to be that in their predictions they take into account only five stars.
What? Think you so many thousand stars shine on in vain? What else, indeed, is it which causes those skilled in nativities to err than that they assign us to a few stars, although all those that are above us have a share in the control of our fate? Perhaps those nearer direct their influence upon us more closely; perhaps those of more rapid motion look down on us and other animals from more varied aspects. But even those stars that are motionless, or because of their speed keep equal pace with the rest of the universe and seem not to move, are not without rule and dominion over us.[[179]]
Seneca accepts a theory of Berosus, whose acquaintance we have already made, that whenever all the stars are in conjunction in the sign of Cancer there will be a universal conflagration, and a second deluge when they all unite in Capricorn.[[180]]
It is on thunderbolts as portents of the future that Seneca dwells longest, however. “They give,” he declares, “not signs of this or that event merely, but often announce a whole series of events destined to occur, and that by manifest decrees and ones far clearer than if they were set down in writing.”[[181]] He will not, however, accept the theory that lightning has such great power that its intervention nullifies any previous and contradictory portents. He insists that divination by other methods is of equal truth, though perhaps of minor importance and significance. Next he attempts to explain how dangers of which we are warned by divination may be averted by prayer, expiation or sacrifice, and yet the chain of events wrought by destiny not be broken. He maintains that just as we employ the services of doctors to preserve our health, despite any belief we may have in fate, so it is useful to consult a haruspex. Then he goes on to speak of various classifications of thunderbolts according to the nature of the warnings or encouragements which they bring.[[182]]
IV. Ptolemy’s Tetrabiblos and astrology.—Astrology was more than a popular belief which extended to men high in social rank and public life; it was held by scientists as well, though naturally in a less naïve and more scientific form. Nevertheless, the astrology of the scientist might be of an extreme enough type and of a more clearly magical variety than we were able to gather from Pliny, who, moreover, does not seem to have been acquainted with any systematic doctrine of the influence of the stars.
Such a systematized treatment Claudius Ptolemaeus set forth in the little volume known as the Tetrabiblos, or Quadripartitum. It would seem as if we ought to be able to regard a book by that noted geographer and astronomer as an example of the best science of his time, the middle of the second century. His works quickly became classics, and in the third century Porphyry commented on the Tetrabiblos. The Arabs eagerly accepted his writings, and it is generally held that in the Middle Ages his word was law in all the subjects of which he treated. The Tetrabiblos, therefore, would seem a landmark in the entire history of astrology as well as a crucial instance of how that branch of magic formed a part of science in the Roman Empire. True, Ptolemy does not cover the whole field of sidereal influence. He limits himself to the effects of the stars on man and does not attempt to trace out how they affect all varieties of matter and of life upon our globe. However, to make the stars control each individual man is the climax of astrology and implies that the heavenly bodies govern everything else here on earth. So the Tetrabiblos is a very satisfactory instance of belief in astrology by a scientist and its contents may well be briefly considered.[[183]]
The first of the four books opens with the trite contention that the art itself is not to be rejected because frequently abused by imposters, and with the admission that even the skilful investigator often makes mistakes owing to the incompleteness of human knowledge. In the first place, our doctrine of the nature of matter rests, Ptolemy says, more on conjecture than on certain knowledge. Secondly, old configurations of the stars cannot be safely used as the basis of present-day predictions. Indeed, so many are the different possible positions of the stars and the different possible arrangements of terrestrial matter in relation to the stars that it is difficult to collect enough instances on which to base judgment. Moreover, such things as diversity of place, of education and of custom must be reckoned with in foretelling the future of persons born under the same stars. But although predictions frequently fail, yet the art is not to be condemned any more than one rejects the art of navigation because of frequent shipwrecks.