In these days, a significant amount of people will celebrate the birth of Jesus of Nazareth, who was definitely a strongly influential character in the adventure of thought.
This article is in a way a small tribute to a genius who was born on December 25, 1642. This person was one of the founders of mathematical physics. He was a human being of an extraordinary talent who changed the world for good. Nothing would ever be the same after the intellectual earthquake he began: wrong ancient ideas which were profoundly rooted into the mindset of the time were put into question; the basis for a new conception of the world was established. The name of this outstanding spirit could not be other than Sir Isaac Newton.
The highly remarkable achievements and the fascinating anecdotes of Newton’s stay on this planet are so numerous that by no means can I be thorough about them in this short text. We shall just mention that by the age of twenty-three (yes, probably quite close to the average age of the people that might be reading this right now) he had invented -or discovered, for Platonists- a whole new field of mathematics (calculus, i.e. the derivatives and integrals that we all love) and he had developed what was to become the law of universal gravitation, namely a mathematical relation which was called to revolutionise human’s existence. Both of these breakthroughs and uncountable more of inestimable value he carried out on his own.
Although he did arrive to all his results without the help of any of his contemporaries, we must not jump to conclusions. We are all sons and daughters of our time, of our family, of our history and not only; in one word, we are all a product of our personal and unique background. Naturally, Newton was not an exception to this rule and all the components of his life played a role in his unmatchable power to see beyond any fixed limit. From his obsession in the search for the Truth in disciplines so diverse such as mathematics, physics, theology or alchemy; to his hard childhood; to his arrogance; and to his fear of conflict: it all had an effect upon his mental universe. Nonetheless, the principal source from which his insightful observations sprouted was -I believe- his readings, a bridge to communicate with people who existed in different spaces and times. Newton compulsively read and studied every book he had in front of him and he was familiar with the philosophical, scientific and mathematical knowledge of his time and this undoubtedly contributed to his own brilliant ideas.
The ideas that had governed the perception of our planet in the cosmos for many centuries were those of Aristotle. The Aristotelian paradigm corrected stated that the Earth is a sphere and that the other planets and the Moon are spheres. However, it was a geocentric model, which means that it claimed that the Earth is on the centre of the universe, immobile, and the other celestial bodies revolve around it. Furthermore, the universe below the orbit of the Moon and beyond it was considered to be two entirely different worlds: on Earth there were four elements (air, fire, earth and water) which moved in a straight line upwards or downwards according to their nature, whereas in the outer space there was only aether, whose motion was always circular. This conception had been accepted by the Catholic Church and it was the dominant perspective when Newton attended university.
From our modern days it is easy to criticise Aristotle’s ideas, but we would not be fair. Aristotle proved to be an exceptional philosopher and scientist and his model did make sense in his world. He would have probably changed his way of thinking if confronted with good evidence. The essential problem was that his writings (only some part of them, actually) were considered to be an incontrovertible truth and that is indeed what attributes to Newton’s findings an even greater relevance.
Young Isaac, following the path of Galileo Galilei, formulated the basic laws of motion. He accepted the definition of space that Democritus had proposed in Ancient Greece, in opposition to that of Aristotle (which has been recently adopted for the modern “loop quantum gravity” theory). And, within his postulated absolute frame of space and time, he described motion in a way so powerful and useful that his physics would remain intact until Einstein’s theories changed the world again in the beginning of the 20th century. Newton’s mechanical description of the universe (for the development of which he invented calculus) also included a description of gravity and this is the most valuable part of his legacy to us. He put the Earth and the celestial realm at an equal level by realising that that the exact same thing that makes an apple fall towards the centre of our planet makes the Moon orbit (to orbit is to “fail to fall”) the Earth and makes all the planets -among them the Earth- orbit the Sun. He discovered that this mysterious pull, this “gravity”, existed everywhere where there was mass and that this always attractive interaction could be expressed with a very simple and elegant mathematical formula. He unified the Earth and the Heavens and this had radical consequences.
There existed a world before Newton and a world after Newton. The scientific and philosophical implications of his revelations to us cannot be exaggerated: for a long time virtually any person of culture admired and was influenced by the English natural philosopher. Everything changed. With his revolutionary thoughts, Newton managed to lay the foundations of the conceptual world that the following generations would be forced to inhabit.
Sir Isaac Newton was a real philosopher, a real scientist. He questioned old ideas and kept only those which passed through his sieve of truth. He built on the basis of solid principles and conceptual tools that had been passed on from the past, just as much as he created his novel way of perceiving reality. He rendered possible a future that would have been impossible to conceive of and he opened new ways to unravelling the enigmas of the cosmos.