The minimum principle that unified the knowledge of light, gravitation, and electricity of Hamilton's time no longer suffices to relate these fundamental branches of physics. Within fifty years of its creation, the belief that Hamilton's principle would outlive all other physical laws of physics was shattered. Minimum principles have since been created for separate branches of physics... but these are not only restricted... but seem to be contrived... A single minimum principle, a universal law governing all processes in nature, is still the direction in which the search for simplicity is headed, with the price of simplicity now raised from a mastery of differential equations to a mastery of the calculus of variations.

Indeed, I think we may concede to our Academician, without flattery, his claim that in the principle [principio, i. e., accelerated motion] laid down in this treatise he has established a new science dealing with a very old subject. Observing with what ease and clearness he deduces from a single principle the proofs of so many theorems, I wonder not a little how such a question escaped the attention of Archimedes, Apollonius, Euclid and so many other mathematicians and illustrious philosophers, especially since so many ponderous tomes have been devoted to the subject of motion. (Galileo referred to himself as the/our Academician in his dialogue)

Condon, quick on his feet, replied that the accusation was untrue. He was not a revolutionary in physics. He raised his right hand: “I believe in Archimedes’ Principle, formulated in the third century B.C. I believe in Kepler’s laws of planetary motion, discovered in the seventeenth century. I believe in Newton’s laws.…” And on he went, invoking the illustrious names of Bernoulli, Fourier, Ampère, Boltzmann, and Maxwell.

... during the last two decades, there has been introduced into physical methodology a principle of utmost philosophical importance, easily rivaling that of relativity, and, in some respects, indeed that of causality. Discovered by Pauli in 1925, it immediately elucidate a whole realm of physical facts and was accepted by physicists with wide acclaim. Called the exclusion principle—or Pauli principle, or principle of anti-symmetry—it was embodied in the axiomatics of quantum mechanics; its pecular methodological significance passed out of view.

Magnetism is, of course, not the same as gravity, but Kepler’s fundamental innovation here is nothing short of breathtaking: he proposed that quantitative physical laws that apply to the Earth are also the underpinnings of quantitative physical laws that govern the heavens. It was the first nonmystical explanation of motion in the heavens; it made the Earth a province of the Cosmos. “Astronomy,” he said, “is part of physics.” Kepler stood at a cusp in history; the last scientific astrologer was the first astrophysicist. Not given to quiet understatement, Kepler assessed his discoveries in these words: With this symphony of voices man can play through the eternity of time in less than an hour, and can taste in small measure the delight of God, the Supreme Artist … I yield freely to the sacred frenzy … the die is cast, and I am writing the book — to be read either now or by posterity, it matters not. It can wait a century for a reader, as God Himself has waited 6,000 years for a witness.

It [science] has as its highest principle and most coveted aim the solution of the problem to condense all natural phenomena which have been observed and are still to be observed into one simple principle, that allows the computation of past and more especially of future processes from present ones. ...Amid the more or less general laws which mark the achievements of physical science during the course of the last centuries, the principle of least action is perhaps that which, as regards form and content, may claim to come nearest to that ideal final aim of theoretical research.

The goal of deriving all the phenomena of nature from a few basic physical laws and the axioms of mathematics had been set by Galileo...
In studying curvilinear motions on the earth Galileo had found the parabola to be the basic curve. In the heavens... Kepler... had found the ellipse to be the basic curve. Why this difference? ...since parabola and ellipse are both conic sections there was the provocative suggestion that perhaps some physical law unified these related paths of motion. ...
It has often happened in the history of mathematics and science that major problems remained outstanding... great minds... succeeded only in revealing the true difficulties... and in generating an atmosphere of dispair... Then a genius appeared... with ideas that seemed remarkably simple once propounded, clarified the entire situation, dispelled the confusion, restored order, and produced a new synthesis that embraced far more even than the phenomena under consideration. The genius who... picked up the torch of science dropped by Galileo, was Isaac Newton.

Perhaps the most profound synthesis of physical sciences came from the realization that everything could be understood from "conservation laws" and symmetry principals.

The physicists of Gilbert's time had recourse to mechanism infrequently, and its effective explanations touched only a few disconnected phenomena. The virtuosity, inventiveness, and optimism of Descartes, however, and the counter-example of latter- day hermetists like Robert Fludd, persuaded many that mechanical models offered the only hope for a precise and comprehensible physics. Expectations rose. Physicists demanded more from models, perhaps even a complete fit with phenomena, with little or no negative analogy.
Gilbert's countrymen , diplomat and philosopher, and Thomas Browne, physician diplomat and literateur, freed his watery humor objections of Cabeo by concocting it into an unctuous, elastic vapor. Such a vapor could allow Cabeo's rebounds, occasion the reattractions of ricocheting that Digby noticed, and — in its elastic contractions — draw the electric as well as the chaff. This last inference was first made about 1660, by the unconventional Cartesian fellow traveller , S.J., 'a veritable giant in science' and a liberal and candid physicist whenever his Society's obligation to combat Copernicans did interfer.

A scientist in the late nineteenth century could be forgiven for thinking that the major elements of physics were built on unshakeable foundations and effectively established for all time. The efforts of generations of scientists, philosophers, and mathematicians had culminated in Isaac Newton's grand synthesis in the late seventeenth century.

It was a dramatic moment in the history of our civilisation when, in about the year 240 B.C., Archimedes leapt out of his bath and ran naked into the street of Syracuse shouting "Eureka" - "I have found it!" He had found the theoretical answer to a practical problem, that of finding the specific gravity of solids, known ever since as "Archimedes' Principle". We know this because Archimedes had written and published many books, on mathematics and mechanics, and some of these have survived and are preserved in libraries for us to use today. He made a major contribution to the progress of humanity, and over the centuries, that progress has been continually stimulated and accelerated by the invention of new theories, new tools and machines, which explain our world, and lighten the burden of securing the basic necessities of life.

As a boy Kepler had been captured by a vision of cosmic splendour, a harmony of the worlds which he sought so tirelessly all his life. Harmony in this world eluded him. His three laws of planetary motion represent, we now know, a real harmony of the worlds, but to Kepler they were only incidental to his quest for a cosmic system based on the Perfect Solids, a system which, it turns out, existed only in his mind. Yet from his work, we have found that scientific laws pervade all of nature, that the same rules apply on Earth as in the skies, that we can find a resonance, a harmony, between the way we think and the way the world works.
When he found that his long cherished beliefs did not agree with the most precise observations, he accepted the uncomfortable facts, he preferred the hard truth to his dearest illusions. That is the heart of science.

Galileo had provided the methodology for the analysis of motions on and near the earth and had applied it successfully. Copernicus and Kepler had previously obtained the laws of motion of the planets and their satellites. ...But Galileo had succeeded in deriving numerous laws from a few physical principles and... the axioms and theorems of mathematics. ...The Keplerian laws ...were not logically related to each other. Each was an independent inference from observations. ...They seemed to be suspended in the same vacuum in which the planets moved.
Galileo's laws had the additional advantage of supplying physical insight. The first law of motion and the law that the force of graviation gives... a downward acceleration of 32 ft/sec²... explain the vertrical rise and fall of bodies, motion on slopes, and projectile motion. Kepler's laws... had no physical basis. ...Kepler tried to introduce the idea of a magnetic force which the sun exerted... But he failed to related the behavior of the planets to the precise laws of planetary motion. ...
The new astronomical theory was completely isolated from the theory of motion on earth. ...it bothered mathematicians and scientists who believed that all the phenomena of the universe were governed by one master plan instituted by the master planner—God.

All three of Kepler’s laws of planetary motion can be derived from Newtonian principles. Kepler’s laws were empirical, based upon the painstaking observations of Tycho Brahe. Newton’s laws were theoretical, rather simple mathematical abstractions from which all of Tycho’s measurements could ultimately be derived. From these laws, Newton wrote with undisguised pride in the Principia, “I now demonstrate the frame of the System of the World.