[A pleasant Venetian villa; through the open window, we see tourists photographing each other with their iPads while gondolas traverse a canal in the background. SALVIATI effusively greets his guests, SAGREDO and SIMPLICIO]
SALVIATI: Welcome, dear friends, and many thanks for answering my urgent convocation! It is my earnest wish that we now devote some hours to mutual discussion, as we have so often done before, but this time on a different topic: to wit, that book written by Galileo in 1629, which has excited so much controversy in the nearly four centuries since it first appeared to an astonished world.
SAGREDO: Indeed, there is nothing that could afford me more pleasure, for I know that no man has greater power than you, Salviati, to penetrate to the heart of things and make the difficult appear simple. I am yours to command, and what little wit I have is entirely at your disposal.
SALVIATI: If my discourse has merit, it is as much due to the keen testing it has received at your hands as to any small ability I may myself possess. And naturally I must also thank Simplicio, who will in his usual way propound the contrary hypotheses, and take it in good part that he is continually refuted and humiliated at our hands. I hope he will understand that it is not done in any spirit of malice, but merely that the truth may be the more plainly seen.
SIMPLICIO: To be honest, I do not know what you are talking about; I feel that, on the whole, I have acquitted myself well in our verbal jousts. But I wonder if we may not proceed to the matters on which we intended to converse; for we have now spent many minutes on these polite exchanges, pleasant as they may be, and I cannot but help that I fear we may be in danger of losing our audience. Indeed, if there were one criticism I feel tempted to level against our Linceian friend's book, it is that it is overlong, and contains too much that is at best of marginal relevance to the subjects it purportedly seeks to treat, and rather tends to divagate into side-channels which with time have lost their urgency and interest.
SALVIATI: You are mistaken, Simplicio, and I will lead you to deduce that from facts that you already know full well. Now tell me, is it not true that a book in many respects is like to a house?
SIMPLICIO: I fail to grasp your meaning. The one is made of words, and the other of bricks and mortar; how could these be the same?
SALVIATI: You are correct, my dear Simplicio, but you do not go far enough in your reasoning. A heap of bricks is no house, just as a list of words is no book. To build a house, you must skillfully arrange the bricks, to form the foundation, then the first storey, then the second, and so on; and similarly, to make a book, the words must be arranged to create the introduction, then the first chapter, then the second, until one reaches the end.
SIMPLICIO: This I grant you.
SALVIATI: Now one may look at a house, and feel that it is overlarge; but if one should remove some of the bricks from a lower storey, what will happen?
SIMPLICIO: It will collapse, of course.
SALVIATI: Exactly so! And in the same way, were we to remove some of the words from this book, the argument would fall of its own accord; for just as the higher bricks in a house are balanced on the lower, so the later words of a book rest on the earlier. Now do you see?
SAGREDO: I, for my part, am quite overcome by the elegance of Salviati's reasoning; truly, if this be the only thing I learn today, I shall count myself well rewarded already. And now I think we must heed Simplicio's warning, and move on to weightier matters, namely the content of the book and the question of how well it has withstood the test of the years.
SALVIATI: An excellent plan. Simplicio, lest you again tax us with losing time in overlong and prolix explanations, I beg you to do us the honour of guiding our conversation in an appropriate direction. What is your opinion here?
SIMPLICIO: Well, surely all the world is now in agreement on this point. Galileo, the revered author of this book, is universally acknowledged as a martyr, maybe even the foremost martyr, of science in its age-old war with religion; time has given him right on each and every point he brought up, and has long covered his ecclesiastical opponents in shame and ignominy. Indeed, his words, Eppur si muove
, have become a veritable rallying-cry for scientists in their fight against base religious superstition.
SALVIATI: Though this phrase does not in fact appear anywhere in the book, and there is some doubt as to whether Galileo ever said it.
SIMPLICIO: This is of little matter. The important thing is Galileo's scientific arguments, which eloquently speak for themselves.
SALVIATI: By his scientific arguments, you mean his proofs that the Earth rotates on its axis and circles the sun, rather than standing still in the center of the universe, as argued by Aristotle and the Peripatetic school?
SIMPLICIO: Quite so, that is exactly what I refer to.
SALVIATI: Now tell me, which of Galileo's several arguments did he consider weightiest and of most significance?
SIMPLICIO: It is some time since I read the Dialogue
; I fear I do not recall it in sufficient detail to be able to answer.
SALVIATI: Then I shall ask you quickly to read the final chapter, so that you can remind yourself of its content. Here, I have brought a copy with me. Well?
SIMPLICIO: It is true, he does consider his argument from the nature of the tides to be the most convincing; and with the advance of scientific knowledge, it would appear that it is not correct in every detail.
SAGREDO: My dear Simplicio, you are too kind to your revered author! To say that it is not correct in every detail is the grossest of understatements; say rather, that it is utterly fallacious from start to finish, and can be readily refuted by arguments which Galileo himself adduces in earlier parts of the book. That he should obstinately have clung to it over the course of two decades and regarded it as the crowning jewel in his life's work is one of the great mysteries of science.
SALVIATI: To make a bad matter worse, Galileo even goes so far as to pour scorn on what later turned out to be the correct hypothesis, namely that tides are caused by the gravitational influence of the moon and sun, as argued by the Catholic priest Marcantonio de Dominis in his 1624 pamphlet Euripus sive sententio de fluxu et refluxu maris
, and he moreover castigates the author as dealing in occult speculations.
SIMPLICIO: I do not know what to say; I find it hard to believe that the great Galileo could have mistaken himself to this extent, and I am sure that a closer reading of the passage will reveal much in his favour. But even if your accusations have substance, which I do not concede, a single slip is hardly of great consequence. The rest of the book is still sound. Otherwise, I doubt that so many great scientists would speak as warmly as they do in Galileo's favour. For example, Bertrand Russell in Science and Religion
refers to him as "the greatest man of his age", while A.D. White in A History of the Warfare of Science with Theology in Christendom
SALVIATI: Let us for the moment leave to one side the opinions of these learned men, and continue with those of Galileo. For example, please tell me a little more about his observations on the paradox of the rotating Earth?
SIMPLICIO: With pleasure. Galileo confronted arguments that the Earth could not rotate, and utterly refuted them. He showed that all motion was relative, in contradiction to the then-established principles of Aristotle; and with his celebrated experiment of dropping an object from the mast of a moving boat--
SALVIATI: Was this experiment ever performed?
SIMPLICIO: I am not sure. But the result is so obvious that this is hardly necessary. A moment's reflection suffices to show that--
SALVIATI: Surely this is not a trivial matter. Galileo repeatedly argues that all points of disagreement must be resolved by experiment; yet, on a point crucial to his theory, he either did not perform the experiment, or gives no details of what was done.
SIMPLICIO: In that case, I am convinced that Galileo did perform the experiment. And since the rest of the argument is clearly sound, this small point of doubt is no more than an academic quibble.
SAGREDO: Steady on, Simplicio! You are sure that the argument is sound?
SIMPLICIO: Quite sure. Though, as I said, I have not read the book recently.
SALVIATI: I think our friend touches here on the question of whether a rotating Earth would throw off all loose objects due to the action of a centrifugal force. Can you tell us how Galileo answered this objection? You may wish to read this passage first.
SIMPLICIO: I am somewhat confused. It appears, on a superficial reading, that Galileo believes himself to have proved that no rotating planet, no matter how quickly it turns, can ever throw off an object into space. But surely it is impossible that Galileo could have meant this; I fear the translator has somehow garbled his words, or given them an unintended meaning.
SALVIATI: And why do you suspect that the translation is at fault?
SIMPLICIO: It is surely obvious! All the world knows that, when Galileo was confronted by the Inquisition, he was utterly in the right, and the the Inquisition in the wrong; why, I have recently read as much in books by Richard Dawkins and the late Christopher Hitchens, peace be upon his memory. Were there such gaps and lacunae in Galileo's reasoning as you suggest, once could well believe that matters were quite unclear, and that the Inquisition were not entirely unreasonable in their methods of proceeding.
SALVIATI: What I am asking is the following: does a close study of the text lead you to this conclusion?
SIMPLICIO: It is hardly important: I am sure that these great thinkers could not be mistaken on such an important matter.
SALVIATI: But my dear Simplicio, Galileo would not wish you to quote authorities in his defence: the entire burden of his argumentation is that one should examine the facts for oneself and ignore the opinions of authorities, be they ever so weighty. I fear it was exactly this obstinacy, which falls dangerously close to the opinions of Luther and Calvin, which prompted the ire of the Holy See, in the person of Pope Urban VIII.
SAGREDO: I am once again struck by the extraordinary insight which Salviati brings to bear on all matters: we are truly fortunate to be in the presence of a man who can render the most difficult matters simple. I feel that I have been stumbling about in the dark all through this discussion, and only now am able to see things in the clear light of day. I will make haste to reread Galileo's book, paying the closest attention to all the matters of which Salviati speaks, so that I can form my own opinion of them. And now, I fear that we have been overtaxing our aimiable friend's hospitality, and we are all wearied by our discussion; so I move that we adjourn the day's proceedings, and continue again tomorrow when our spirits have been refreshed.