Essential Thinkers #19 Isaac Newton, the Man Who Discovered Gravity

“This most beautiful system of the sun, planets and comets, could only proceed from the counsel and dominion of an intelligent and powerful Being.”
(Isaac Newton)

A mathematician and physicist, Sir Isaac Newton (1642-1727) produced work – philosophical to a degree – which served mainly as an impetus and basis for many of the philosophers of his and succeeding generations, including John Locke and Immanuel Kant, who both owed much to him. Newton’s principal work, the Philosophiae Naturalis Principia Mathematica contains his theory of gravity and laws of motion. His later work, the Opticks, is primarily concerned with optical physics but also contains speculations on mechanics, religion and morals. He was to be involved in a series of disagreements with Gottfried von Leibniz, initially over which of them was the first to invent the calculus, and later over the issue of the status of space and time.

The insight behind Newton’s physics was that the universe runs according to law-governed mechanical principles. This idea was to have a profound influence on John Locke, whose philosophy may be seen as the philosophical working out of Newton’s physical principles. Locke was determined to make sense of human understanding in a way consistent with Newtonian mechanics. As a result, he argued for a causal theory of perception and for a distinction between primary and secondary qualities of objects.

Emmanuel Kant, in similar fashion, recognized that everything in the phenomenal world had to conform to Newton’s principles, but that this order was for the most part imposed by the psychological apparatus of the mind. Kant’s philosophy gave support to Newton in the quarrel with Leibniz over whether space and time should be conceived of as absolute or merely as relations between objects. The debate seemed to have been won hands down by the Newtonians until the advent of Einstein’s relativistic physics.

Claiming that his method was empirical and inductive, rather than rationalist and deductive, Newton was also fond of criticizing Rene Descartes. It is thanks to Newton that empiricism began to enjoy a period of dominance over rationalist philosophy. However, Newton owed much to Descartes’ thought, and it is likely his own speculations could not have begun but for the work already undertaken by his rationalist predecessor.

Undoubtedly, Newton’s greatest achievement was his theory of gravity, from which he was able to explain the motions of all the planets, including the moon. Newton proved that every planet in the solar system at all times accelerates towards the sun. The acceleration of a body toward the sun is at a rate inversely proportional to the square of its distance from it. This led to Newton’s law of universal gravity: “every body attracts every other with a force directly proportional to the product of their masses and inversely proportional to the square of the distance between them.” The law of universal gravity allowed Newton to predict all of the planetary motions, the tides, the movements of the moon and of the comets.

It was a striking achievement that would not be superseded until Albert Einstein, although even with the advent of Einsteinian relativity, Newton’s mechanics still holds good – and indeed is still used, on account of its simplicity, for predicting the movement of so-called ‘medium-sized’ objects – anything that is neither bigger than the solar system nor smaller than the eye can see. Newton’s work is profound and remarkable achievement in the history of human thought.

[Summarized from Philosophy 100 Essential Thinkers by Philip Stokes, 2012.]

Lord, Give Us Today Our Daily Idea(s)

Essential Thinkers #18 Galileo Galilei: The Quest for Knowledge Amidst Religious Dogmatism

Italian philosopher, astronomer, scientist and mathematician, Galileo Galilei (1564 – 1642) is probably best remembered for his work in support of Copernicus’ heliocentric theory of the solar system. For the sake of his life, Galileo recanted his views in 1633, admitting that the earth did not spin on its own axis. It is unlikely that the recantation was sincere and he nevertheless remained under house arrest.

In 1608 the Dutchmen Lippershey invented the telescope. Within two years Galileo used it to dramatic effect, showing by his astronomical observations that the Ptolemaic or geocentric theory which held that the Earth was at the centre of the universe, was seriously flawed. Galileo also observed that the Milky Way was in fact made up of many millions of individual stars. He observed the phrases of Venus and discovered the moons of Jupiter, which had theological experts up in arms. Indeed, Galileo’s findings attracted such sharp criticism, both from secular and ecclesiastical quarters that he felt compelled to offer, both in his defence and in reply to his critics, the Letter to the Grand Duchess Christina in 1615. In the Letter, Galileo argues that scientific and theological matters should not be confused. Science could not cast doubt on religious doctrine, only strengthen it. Nonetheless he was condemned by the Inquisition, first in private communication in 1616 and later in 1633, when he publicly recanted.

Although his work was instrumental in bringing the Copernican system into prominence, Galileo was far more than just an astronomer. Much of his important work lay in dynamics and the principles of movement. He was the first to discover the law of falling bodies, or constant acceleration, published after his recantation and whilst still under house arrest in 1638, in his Discourse on Two New Sciences.

Moreover, what would later be Newton’s celebrated first Law of Motion was directly taken from Galileo’s principle of inertia, namely that a body moves in a straight line with uniform velocity unless acted upon.

This principle was important in helping to support the Copernican theory. Critics of Copernicus had claimed that if the heliocentric theory were true, then a falling body should not fall in a straight line, but in fact land somewhat to the west of the point from which it was dropped, on account of the eastwise rotation of the Earth. It had been proven by experiment that this was not the case, a result which led many to dismiss Copernicus as wrong even if they did not share the religious reasons for dismissing him. It took Galileo’s work in dynamics to show why the prediction was not fulfilled. Simply put, the falling stone retains the rotational velocity of the Earth.

Philosophically, Galileo held that “the book of nature is written in the language of mathematics.” He was heavily influenced by Greek philosophy and a great admirer of Archimedes. He also maintained, like John Locke, that there was a metaphysical distinction between the primary and secondary qualities of bodies. The former are essential and inherent in objects, whereas the latter exist only insofar as they cause certain effects in the minds of observers. Undoubtedly, Galileo was a great thinker who risked much in the pursuit of truth, helping to set free the quest for knowledge from the chains of religious dogmatism.

[Summarized from Philosophy 100 Essential Thinkers by Philip Stokes, 2012]

Lord, Give Us Today Our Daily Idea(s)

Renaissance Innovators who Challenge Orthodoxies (Nonconformists Wins)

Perhaps the first thing that comes to mind when we think about Renaissance innovators is their contrarian spirit. It was a time when people began to ask sceptical questions that had never been asked before, and to challenge deeply entrenched beliefs that had long been taken for granted. For examples:

Copernicus, Galileo, and Kepler asked:

“What if the Earth is not the centre of the Universe? What if it revolves around the Sun along with the other planets?”

Martin Luther asked:

“What if the papacy and the dogma of the Roman Catholic church are actually wrong? And what if we could read the Bible and listen to sermons in our own language, instead of in Latin?”

Petrarch asked:

“What if a person can achieve great things in this world without being ungodly? What if God wants us to use the intellectual and creative powers he gave us to their fullest potential?”

Andreas Vesalius asked:

“What if the dominant theories of human anatomy that have been unassailable for a thousand years are fully misguided? What if the human body functions completely differently than we have been taught? And what if we started dissecting some dead bodies to find out the truth?”

Paracelsus asked:

“What if everything we know about medicine is nonsense? What if certain chemicals and minerals, used in the right dosage, would be a far better way to cure illnesses than traditional practices? What if nature could teach us more about medicine than ancient books from Greece and Rome?”

Machiavelli asked:

“What if politics has nothing to do with theology or morality? What if it’s simply about using all means – fair and foul – to retain power?”

Descartes asked:

“What if all of our traditional systems of thinking, most of which are founded upon Aristotle’s ideas, are false? What if we set out to build a new philosophical system from the group up, by first doubting everything we think we know?”

Isaac Newton asked:

“What if conventional concepts of physics, gravity, and motion are inconsistent with reality? What if we need new laws and mathematical models for understanding mechanics?”

Filippo Brunelleschi and Leon Battista Alberti asked:

“Why can’t a painting be less like wall decoration and more like a window into the nature world? What if we used mathematical and optional principles to imitate objects so accurately that they look entirely real?”

Christopher Columbus asked:

“What if we could get to the East Indies much faster by sailing west instead of east and circumnavigating the globe?”

Amerigo Vespucci asked:

“What if the Earth has a much larger circumference that we learned from Ptolemy’s cartography? What if these lands Columbus has newly discovered are not the Indies at all, but in fact another whole continent – a New World?”

Almost by definition, the Renaissance revolutionaries were nonconformists who were willing to contest previously held truths – beliefs and assumptions that had been accepted as absolute truth for perhaps a thousand years or more – and to reinvent their worldview completely from scratch. Many of them were branded as heretics or lunatics. Yet their propensity to break the chains of precedent and to challenge conventional thinking became the basis for a whole string of breakthrough discoveries and new philosophies that literally changed our world.

[Questions are taken from The 4 Lenses of Innovation (2015) by Rowan Gibson. Title mine]

Lord, Give Us Today Our Daily Idea(s)

Creative People are Dynamic

Unlike most people, creative people do not allow their minds to become passive, accepting, unquestioning. They manage to keep their curiosity burning, or at least to rekindle it. One aspect of this intellectual dynamism is playfulness. Like little children with building blocks, creative people love to toy with ideas, arranging them in new combinations, looking at them from different perspectives.

It was such activity that Isaac Newton was referring to when he wrote,

“I do not know what I may appear to the world; but to myself I seem to have been only like a boy playing on the seashore, and diverting myself in now and then finding… a smoother pebble or a prettier shell than ordinary whilst the great ocean of truth lay all undiscovered before me.”

Albert Einstein was willing to speculate further. He saw such playfulness as “the essential feature in productive thought.” But whatever the place of playfulness among the characteristics of creative people, one thing is certain: it provides those people a richer and more varied assortment of ideas than the average person enjoys.

Lord, Give Us Today Our Daily Idea(s)

Taken from Vincent Ryan Ruggiero’s The Art of Thinking: A Guide to Critical and Creative Thought (8^th Edition), (United States: Pearson Education, Inc., 2007) pg. 90