“Because if you do not, Sir Isaac, others, of less brilliance, will; and they will frame the wrong ones,” Caroline said.
Newton bristled. “My work on gravity and opticks has brought me a kind of fame, which is a thing I never sought, nor wanted. It has done me nothing good, and much bad-as now, when I am expected to utter profundities on topics far afield from what I have chosen to study.”
“So says the public Sir Isaac Newton,” said Daniel, “Author of Principia Mathematica, and Master of the Mint. But this is a private gathering, which might benefit from the participation of the private Sir Isaac: the author of the Praxis.”
“Praxis has not been published,” Isaac pointed out, “and not because I have deemed it somehow private but because ’tis yet unfinished, and so not fit to talk of.”
“What is Praxis?” Caroline inquired.
“What Principia Mathematica was to Mechanical Philosophy, Praxis would be to Alchemy,” said Isaac.
“A laconic answer! May we hear more?”
“If I may say so, highness,” said Daniel, “Sir Isaac learned early that anything he openly professed was liable to come under attack, to his great aggravation and embarrassment, and so became chary of professing anything until he had got it perfect, and made it impervious. Praxis is not ready yet.”
“Then it seems I shall not have any satisfaction whatsoever!” said Caroline, a bit poutingly.
“Which is entirely my fault, for having mentioned Praxis,” Daniel hastened to say. “But I had a reason for doing it, which was to say that, though the public Sir Isaac might profess not to see the problem that so captured the attention of Descartes, I believe that the private Sir Isaac has been working on just that problem.”
“As I state quite plainly in Principia Mathematica,” said Isaac, in a bit of a high clarion self-righteous tone, “it is not my intention, in that work, to consider the causes and seats of Force. That gravity exists, and acts at a distance, is taken as a given. Why and how it does so are not considered. I would not be human if I did not have some curiosity as to what gravity was, and how it works; and even if ’twere otherwise, Baron von Leibniz and his Continental supporters would never allow me a moment’s peace on the matter. So, yes! I would understand Force. I have toiled at it. The ignorant have styled my toils Alchemy.”
At this Daniel threw him an irritated look, which Isaac, to his credit, did not fail to notice. “C’est juste!” Isaac said. “It’s not wrong to call this work Alchemy, but that word, so laden with the baggage of centuries, doesn’t do justice to it.”
“May I ask a question about your research in this area-however you choose to denote it?” Leibniz asked.
“Provided it contains no hidden barbs or spryngs,” Isaac allowed.
Leibniz now achieved the difficult feat of rolling his eyes, heaving a great sigh of exasperation, and voicing his question all at the same time. “If I understand what ‘force’ means, in your metaphysicks-”
“Which is the only coherent definition of ‘force’ that I know of!” Newton slipped in, glancing at the Princess.
Leibniz, with some visible straining, affected a saintly mien during this. “It appears to mean some invisible influence, acting across what you think of as the vacuum of space at infinite speed, which causes objects to accelerate-even though nothing seems to be touching them.”
“Setting aside your strangely hedged and qualified way of talking about ‘vacuum’ and ‘space,’ that is a reasonable description of gravitational force,” Newton allowed.
“Now in your metaphysicks-which I concede happens to be that used by just about everyone-there is this thing called space, which is mostly empty, but has lumpy bits here and there, called bodies; some big heavy spherical ones which we call planets, but also any amount of clutter, such as this poker, yonder candelabrum, the rug, and these bipedal animated bodies answering to the names Daniel Waterhouse, Princess Wilhelmina Caroline of Brandenburg-Ansbach, et cetera?”
“That much is so obvious that some of us are amazed to hear a learned man waste breath pointing it out,” said Newton.
“Some of those bodies answer only to the deterministic laws of the mechanical philosophy,” said Leibniz, “such as the globe, which rolled into the fireplace because her royal highness gave it a shove. But the bodies denominated Daniel Waterhouse, et cetera, are somehow different. True, they are subject to the same forces as the globe-our friend Daniel plainly feels Gravity’s pull, or else he would float away! But such bodies act in complicated ways not explainable by the laws set forth in your Principia Mathematica. When Dr. Waterhouse sits down to write an essay, let us say about the Latitudinarian philosophy espoused by him and the late Mr. Locke, we may observe his quill maneuvering all over the page in the most complicated paths imaginable. Here are none of the conic sections of the Principia! No equation can predict the trajectory of Daniel’s nib over the page, for it results from innumerable and unfathomable minute contractions of the small muscles of his fingers and his hand. If we dissect a man’s hand, we find that these muscles are governed by nerves, which may easily enough be traced back to the brain, as rivers come from springs in the mountains. Remove the brain, or sever its connexions to the hand, and lo, that limb becomes as simple as yonder globe; that is, we may predict its future movements from the Principia, and plot them in Conics. And so it is evident that, to the Force of Gravity-which acts on everything-are superadded other forces, observable only in animals,* and productive of infinitely more complicated and interesting movements.”
“I am with you so far,” said Newton, “if all you are saying is that forces other than Gravity act on Dr. Waterhouse’s pen when he is writing something, and that such forces do not appear to motivate rocks or comets.”
“Hooke was fascinated by muscles,” Daniel put in, “and looked at them under his microscope, and labored at making artificial ones, so that he could fly. Those, I predict, could have been described by Mechanical Philosophy; after all, they were naught more than practical applications of the Rarefying Engine, and as such, subject to Boyle’s Law. With more time and better microscopes, Hooke might have found, within muscles, tiny mechanisms, likewise describable by mathematical laws, and thereby put to rest any supposed mysteries-”
But he stopped as both Newton and Leibniz were making the same sort of hand-waving gestures employed to bat away farts. “You miss the point!” said Leibniz. “I have no interest in the physics of muscles! Think, sir, if Hooke had made his flying-machine, driven, in a deterministic fashion, by Rarefying Engines, what more then would he have had to add to this device, to make it flutter to a safe perch atop the cupola of Bedlam, and balance there as ’twas buffeted by divers wind-gusts, and take flight again without o’ersetting and tumbling to the ground like a shot squab? I am trying to draw our attention to what it is that comes down those nerves from the brain: the decisions, or rather, the physical manifestations thereof-the characters, as it were, in which they are writ-and transmitted to the muscles, that they may inform what would otherwise be without form and void.”
“I understand that,” said Daniel, “and I say it is all pistons and cylinders, weights and springs, to the very top. And that’s all I need to explain how I inform ink on a page, and how a bird informs the air with its wings.”
“And I agree with you!” said Leibniz.
This produced a dumbfounded pause. “Have I converted you to the doctrine of Materialism so easily, then?” Daniel inquired.
“By no means,” said Leibniz. “I say only that, though the machine of the body obeys deterministic laws, it does so in accordance with the desires and dictates of the soul, because of the pre-established harmony.”