Essay on the Theory of the Earth

by baron Georges Cuvier

Hence our readers may conclude, that the inferences drawn from the alleged perfection of astronomical science among ancient nations, is not more conclusive in favour of the excessive antiquity of those nations, than the testimonies which they have adduced in reference to themselves.

But had this astronomy been more perfect, what would it prove? Has the progress been calculated which this science ought to make among nations who were not in any degree in possession of others; to whom the serenity of the sky, the necessities of the pastoral or agricultural life, and their superstitious ideas, would render the stars an object of general attention; where colleges, or societies of the most respectable men among them, were charged with keeping a register of interesting phenomena, and transmitting their memory; and where, from the hereditary nature of the profession, the children were brought up from the cradle in the knowledge of facts ascertained by their parents? Supposing that, among the numerous individuals of whom the cultivation of astronomy was the sole occupation, there should happen to be one or two possessed of extraordinary talents for geometry, all the knowledge acquired by these nations might be attained in a few centuries.

Since the time of the Chaldeans, real astronomy has only had two eras, that of the Alexandrian school, which lasted 400 years, and that of our own times, which has not existed so long. The learned period of the Arabians scarcely added any thing to it; and the other ages have been mere blanks with regard to it. Three hundred years did not intervene between Copernicus and the author of the Mecanique Céleste; and can it be believed that the Indians required thousands of years to arrive at their crude theories?

The Astronomical Monuments left by the Ancients do not bear the excessively remote dates which have been attributed to them.

Recourse has therefore been had to arguments of another kind. It has been pretended that, independently of the knowledge which these nations may have acquired, they have left monuments which bear a date fixed by the state of the heavens which they represent, and one that refers to a very remote antiquity. The zodiacs sculptured in two temples of Upper Egypt, are adduced as furnishing proofs perfectly demonstrative of this assertion. They present the same figures of the zodiacal constellations as are employed at the present day, but distributed in a manner peculiar to themselves. The state of the heavens at the period when these monuments were delineated, is imagined to have been represented by this distribution, and it has been thought that it would be possible from it to infer the precise period at which the edifices containing them were erected[212].

But to arrive at the high antiquity which is supposed to be deducible from this, it must, in the first place, be supposed, that their division has a determinate relation to a certain state of the heavens, dependent upon the precession of the equinoxes, which causes the colures to make the tour of the zodiac in 26,000 years; that it indicated, for example, the position of the solstitial point; and, secondly, that the state of the heavens represented was precisely that which took place at the period when the monument was erected,—two suppositions which themselves, as is evident, suppose a great number of others.

In point of fact, are the figures of these zodiacs the constellations,—the true groups of stars which at present bear the same names, or merely what astronomers call signs, that is to say, divisions of the zodiac proceeding from one of the colures, whatever place this colure occupies? Is the point at which these zodiacs have been divided into two bands, necessarily that of a solstice? Is the division of the side next the entrance, necessarily that of the summer solstice? Does this division indicate, even in general, a phenomenon dependent upon the precession of the equinoxes? Does it not refer to some period the rotation of which would be less; for example, to the moment of the tropical year when such or such sacred years of the Egyptians commenced, which, being shorter than the true tropical year by nearly six hours, would make the tour of the zodiac in 1508 years? Lastly, whatever signification it may have had, has it been intended by it to mark the time when the zodiac was sculptured, or that when the temple was built? Has not the object been to record a previous state of the heavens at some period which was interesting in a religious point of view, whether it had been actually observed, or inferred from a retrograde calculation?

From the mere announcement of such questions, it will be perceived how complicated they necessarily are, how much subject to controversy any solution that might be adopted on this subject would be, and how little qualified to serve as a solid proof, for the solution of another problem, such as the antiquity of the Egyptian nation. And it may be said, with regard to those who have attempted to infer a date from these data, that there have arisen as many opinions as there have been authors.