Origin of the “Dialogues.”—Their Popular Style.—Significance of the name Simplicius.—Hypothetical treatment of the Copernican System.—Attitude of Rome towards Science.—Thomas Campanella.—Urban VIII.’s Duplicity.—Galileo takes his MS. to Rome.—Riccardi’s Corrections—He gives the Imprimatur on certain Conditions.—Galileo returns to Florence to complete the Work. It is a curious fact that the very work which was destined to be one of the most powerful levers in obtaining general recognition for the true order of the universe originated in what we now know to be an erroneous idea. The famous book, “Dialogues on the Two Principal Systems of the World, the Ptolemaic and Copernican,”[211] arose out of the treatise on the tides which Galileo wrote at Rome, in 1616, at the suggestion of Cardinal Orsini.[212] The important influence of these “Dialogues,” both on science and the subsequent fate of the author, obliges us to discuss them more particularly.
The book contains a great deal more than is promised by the title; for the author included in it, in connection with the discussion of the two systems, nearly all the results of his researches and discoveries in science, extending over nearly fifty years. He also endeavoured to write in a style which[128] should be adapted not for the learned world alone, but which would be both intelligible and attractive to every educated person; and in this he attained complete success, for he wished by means of this book to extend as widely as possible a knowledge of the true order of nature. The form of the work was most happily chosen. The results of the researches of a lifetime were not given to the reader in a work redolent of the pedantry of the professor’s chair, in which scientific demonstrations drag on with wearisome monotony, but in the lively form of dialogue, which admitted of digressions and gave the author scope for displaying his seductive eloquence, his rare skill in dialectics and biting sarcasm—in short, for his peculiarly brilliant style.
The dialogue is carried on by three interlocutors, two of whom adduce the scientific reasons for the double motion of the earth, while the third honestly tries to defend the opinions of the Aristotelian school with all the scientific means at his disposal, and as these did not suffice, with the arts of sophistry also. If he has but little success, the fault lies with the cause he advocates. Galileo gave to the defenders of the Copernican system the names of his two famous pupils and friends, neither of them then living, Filipo Salviati, of Florence, and Giovan Francesco Sagredo, senator of Venice, thereby erecting a better monument to them than he could have done in marble. Salviati is the special advocate of the Copernican theory. Sagredo takes the part of an educated layman, intelligent, impartial, and desirous to learn. The advocate of the Ptolemaic system was called briefly Simplicius, a pseudonym over which the learned have often puzzled their heads. Did he give this name of simpleton satirically to the champion of the ancient system, or was it merely an allusion to Simplicius, the commentator of Aristotle, as Galileo stated in his “Avviso al lettore?”
The selection of this name is characteristic of the ambiguous attitude which the author maintains in his “Dialogues.” The sarcastic vein is obvious throughout, but is ingeniously concealed[129] behind a mask intended to inspire confidence. Salviati conducts the arguments for the Copernican theory with such convincing force and clearness, and annihilates so completely all the objections of the unfortunate Simplicius, that no unbiassed reader can fail to perceive the scientific superiority of the modern theory to the old. And as Galileo conscientiously puts in the mouth of the Peripatetic philosopher every possible argument in favour of the Aristotelian cause, as well as the objections to the other side, the total defeat of its advocate is a victory all the more brilliant for the immortal Canon of Frauenburg.
The condition that the Copernican doctrine is only to be employed as a hypothesis is ostensibly fully complied with. If Salviati or Sagredo demonstrate to Simplicius the untenableness of some Ptolemaic axiom, or add an important stone to the Copernican structure, Galileo hastens to interpolate some remark to weaken the impression. It must be confessed, however, that the agreement of this “hypothesis” with all the phenomena of nature is as clear as daylight; and when, for instance, it is said that the final decision in the present controversy rests neither with mathematics and physics, nor with philosophy and logic, but solely with a “higher insight,” or when Salviati repeatedly asserts that he does not in the least wish to maintain the truth of the Copernican doctrine, but applies the word “possibly” to it, or speaks of it as a “fantasia” or “vanissima chimera,” the reader cannot fail to perceive that these prudent reservations, which always occur at critical passages, are made with the sole purpose of rendering the publication of the work possible.
The preface and conclusion have no logical agreement with the contents of the “Dialogues,” and owe their origin to the same motive. In the preface the ecclesiastical prohibition of 1616 to teach that the earth moves, is actually called a “salutary edict” (un salutifero editto)! The reader learns further, to his no small astonishment, that the purpose of this comprehensive work is to refute the wholly unfounded opinion[130] which has gained much credit abroad, that this adverse judgment of Rome was not the result of mature deliberation, but merely of the hasty impulse of judges who were not qualified to decide on these questions of natural science. Galileo asserts that his zeal did not permit him to keep silence in face of those audacious accusations, and that being in possession of all the circumstances connected with that prudent decision, he felt constrained to bear witness to the truth before all the world. In bringing forward here all his speculations on the Copernican doctrine, he wished to show that at Rome, where he had taken part in the consultations, they had been fully aware of all the arguments which could be adduced in favour of the new doctrine.[213]
On the origin of this singular introduction, a point on which divergent and often unwarranted opinions prevail, we shall enter in detail in its right place.
The conclusion of the work, which is divided into four “days,” agrees no better with the rest of the contents than the preface. Although the Copernicans everywhere gain the day, Galileo takes care, for very good reasons, not to draw any conclusions from it on the fourth day. The discussion ends apparently without coming to any result. Salviati disclaims any wish to force an opinion on any one which seemed to him a “chimera” or a “paradox.” Addressing himself to Sagredo, he remarks that Sagredo had often agreed with the opinions he had expressed, but he thinks that this was often more from their originality than their conclusiveness. Having therefore thanked him for his “polite indulgence,” he apologises to Simplicius for the eagerness of his language, and assures him that he had no intention of offending him, but rather of inducing him to communicate his sublime ideas (!), which would certainly be instructive to himself. In conclusion, they agree to meet again for a final discussion.[214]
Did Galileo really intend to add a fifth day? Martin[131] thinks it probable, “for,” he says, “Galileo might at that period still have hoped that the ecclesiastical authorities would tolerate the new system during his lifetime, especially should some new discovery, as, for instance that of a small annual parallax of the fixed stars, afford certain proof in favour of his system. In that case Galileo would have been at last allowed to express his opinions without reserve.”[215] We think it very possible, indeed probable, that Galileo did intend to add a fifth day at a favourable opportunity, in which he would have given the result of the previous discussions; but he certainly was not waiting for “some new discovery.” It was his firm conviction that none was wanted, since his telescopic observations amply proved the truth of his theory; neither would the most convincing discovery have enabled him to express his views without reserve, for they had by no means been condemned by the clergy from want of proof, but as “foolish and absurd philosophically and formally heretical.”
We are quite aware that certain writers who have assumed the task of defending the action of the curia against Galileo, maintain that the ecclesiastical party objected to the new system because its accordance with the phenomena of nature had not been sufficiently p............