link: Newton

 

                                         NEWTON: THE MECHANICAL UNIVERSE

 

    It was Newton who realized the 'Cartesian dream' and completed the 'Scientific Revolution'. Newton developed a complete mathematical formulation of the mechanistic view of nature. He formulated a theory of mechanics which contained three laws and one assumption.

Newtonian physics which was the crowning achievement of seventeenth century science, provided a  consistent mathematical theory of the world that remained the solid foundation of scientific thought well into the twentieth century.

" Newton unified the two trends and developed the methodology upon which natural science has been based ever since. ...The stage of the Newtonian universe , on which all physical phenomena took place, was the threedimensional space of classical Euclidean geometry. All changes in the physical world were described in terms of a separate dimension, time,which again was absolute having no connection with the material world and flowing smoothly from the past through the present to the future. Thge elements of the Newtonian world which moved in this absolute space and absolute time were material particles....The Newtonian model of matter was atomistic...all the particles were thought to be made of the same material substance. ..The motion of the particles was caused by the force of gravity which acted instantaneously over a distance....both the particles and the force of gravity created by God... The physical phenomena themselves were not thought to be divine in any sense, and when science made it more and more dificult to believe in such a god, the divine disappeared completly from the scientific worldview, leaving behind the spiritual vacuum that has become characteristic of the mainstream of our culture. The eighteenth and nineteenth centuries used Newtonian mechanics with tremendous success... The picture of the world as a perfect machine, which had been introduced by Descartes, was now considered a proved fact and Newton became its symbol." (Capra The Turning Point 67)

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Francis Bacon and 'inductive method'...   Descartes and 'deductive method'...   Newton and 'scientific method'...

laws of motion...   law of gravity...

 shift from Newtonian mechanics to quantum mechanics...

Sixteenth and seventeenth centuries  In the sixteenth and seventeenth centuries there was a radical change in the 'medieval worldview' or 'paradigm'. The notion of an organic, living and spiritual universe was replaced by that of the world as a machine. It was the world machine which became the dominant metaphor of the modern era. This development was brought about by revolutionary changes in physics and astronomy, culminating in the achievements of Copernicus, Galileo and Newton. Isaac Newton (1642-1727) was born in England in the same year that Galileo died.

In seventeenth century science before Newton there had been two opposing methods of science - the empirical ‘inductive method’ and the rational ‘deductive method’.

The inductive method was devised by Francis Bacon  The inductive method involved empirical observation, systematic experimentation, experimental evidence and inductive reasoning - a theory making process devised by Francis Bacon. Bacon’s inductive method was effective within the framework of the paradigm based on the notion that the understanding of the physical world depends on understanding its determinate laws of cause and effect i.e. ‘determinism’.

The deductive method was defined by Rene Descartes  The deductive method was a  theory-making process defined by Rene Descartes who had created the conceptual framework for seventeenth century science with his view of nature as a perfect machine - a view which remained a vision during his lifetime. The deductive method involved deduction from first principles... deductive reasoning,  systematic interpretation and mathematical analysis.  

Newton emphasized that neither method by itself would lead to reliable theory and went beyond both Bacon and Descartes.

Newton combined the two methods Newton claimed that reliable theory is derived from the correct combination of the both inductive and deductive methods.

 Experimental evidence of the inductive method should be combined with the systematic interpretation by deduction from first principles i.e. deductive logic from a given premise. Newton combined deductive logic from a given premise with inductive reasoning from empirical observation and from the combination he derived a tentative premise known as a 'hypothesis'. The hypothesis had substantiated with evidence... It had to be tested with empirical observation and experiment to be validated. The job of the scientist was to be an 'objective' observer, measure the objects, and then explain the causes for their interactions. This was how the laws of nature were thought to be discovered.

In unifying the two methods Descartes developed the methodology upon which natural science has been based ever since... 'scientific method'...

Quest for understanding natural law depends on experiment (empirical observations or facts') and reasoning Newton taught that the quest for the further understanding of reality would only be possible if it were based on the notion that the universe is governed by laws which can be understood rationally and which can be applied experimentally as well.

Since only simple interactions could be tested, modern science developed as the science of Galileo and Newton. It could handle relatively simple relationships between forces or bodies, and it presented a world picture of a universe that is reducible to such relationships in all essential respects.

Newtonian science looked upon the physical universe as an exquisitely designed giant mechanism, obeying elegant deterministic laws of motion. Complex sets of events could be understood by this science only when broken down to their elementary interactions.

Whatever was clearly known behaved like a reliable mechanism and the rest was assumed to do likewise (with the possible exception of 'mind' - a phenomenon which Newtonian science could not even begin to comprehend).

  First law of motion  Newton's first great contribution to science was the 'law of motion' which stated that an object moving in a straight line will continue to do so forever unless acted upon by an  external force. Furthermore, the direction and speed of a moving object will be altered according to the direction, mass and speed of the force acting upon it.

Law of 'gravity'  Newton's second great contribution was the 'law of gravity' which stated that the

same force pulling an apple downward keeps the moon in orbit around the earth and the planets

around the sun.

 

When he was twenty three years old, Newton used the process of induction to  correlate the observations of Copernicus, Kepler, Bacon, Galileo, and Descartes and accomplished a

synthesis of their works. Kepler had derived empirical laws of planetary motion by studying

astronomical tables ... Galileo had performed ingenious experiments to discover the laws of falling

bodies. Newton combined those two discoveries...According to legend, the decisive insight occurred

to Newton in a sudden flash of inspiration when he saw an apple fall from a tree. He realized that the

apple was pulled toward the earth by the same force that pulled the planets toward the sun. This was

the key to his grand synthesis - his theory of gravitation – which was the formulation of the general

 laws of motion governing all objects in the solar system, from stones to planets.     

Newton's theory of gravitation was originally a hypothesis which was tested with empirical observation. According to the theory of gravitation, the universe - the 'Newtonian universe' - in which all physical phenomena took place, was perceived in terms of the 'three dimensional space' of classical Euclidean geometry. All changes in the physical world were described in terms of a separate fourth dimension - 'time' - which was considered to be separate from the three dimensions of space. As a separate dimension, time was thought to have no connection with the material world and was perceived as flowing smoothly from a past through a present and towards a future. Time was an absolute.

Mathematical Principles of Natural Philosophy (Principia)  Newton presented his theory to the world in great detail in his Mathematical Principles of Natural Philosophy. He described the mixture of both methods in his Principia as the work is usually called for short after its original Latin title. The Principia comprises a comprehensive system of definitions, propositions, and proofs which scientists regarded as the correct description of nature for more than two hundred years.With his work, he laid the foundation for higher mathematics, celestial mechanics and physical optics. His theories were used to describe the movements of the planets, the formation of tides, the paths of cannonballs, and many other phenomena in a mechanical universe. The picture of the world as a perfect machine, which had been introduced by Descartes, was now considered a proved fact and Newton became its symbol.

Newton's model of matter was atomistic Using his own mathematics, he tested his ideas and compared his predictions with observations made by astronomers, thus demonstrating that both earthly and celestial masses are governed by the same laws of motion and gravity. The world was thought to be a mechanism, made up of a large number of uniformly behaving parts.

 Newton's model of the matter in the universe was 'atomistic'. The elements of the Newtonian universe which moved in absolute space and absolute time were material particles all thought to be made of the same material substance. The motion of the particles was assumed to be caused by the force of gravity acting instantaneously over a distance. Both the particles and the force of gravity were believed to be created by God but the physical phenomena themselves were not thought to be divine in any sense.

 Continued progress in science made it more and more difficult to believe in a God and eventually the divine disappeared completely from the scientific worldview.     

Newton's 'mechanics' was crowning achievement of seventeenth century science Newtonian mechanics was the crowning achievement of seventeenth century science. It provided a consistent mathematical theory of the world that remained the solid foundation of scientific thought in the eighteenth and nineteenth centuries when it was used with tremendous success.

Consider Newton's theories in their historical context   Looking at Newton's theories in their historical context, one can appreciate that they were remarkable. He based his theories on sound experimental evidence and described events which were unobservable in the l600s.

Newton's physics was a direct challenge to the power of the church which had been considerable for fifteen hundred years.

 Consider the philosophical implications of Newtonian physics. His new science which he called 'natural philosophy' vindicated the importance of the human individual in the universe.

 Newton interpreted his physical laws as manifestations of 'God's perfection'... Newton regarded the  universe as a great machine. Contrary to the authoritarian position of the church, his criteria for the validity of a hypothesis was the ability to reproduce the experiment and get the same results. During the Inquisition and shortly before Newton's birth, Galileo had been forced to recant his theory of the revolution of the earth around the sun. His philosophical viewpoint justified the notion that predictions about the future could be made on the basis of an understanding of events in the present.

 But in time even the paradigm of Newtonian mechanics was called into question.

End of nineteenth century  At the end of the nineteenth century Newtonian mechanics had lost its role as the fundamental theory of natural phenomena. Concepts that clearly went beyond the Newtonian model indicated that the universe was far more complex than Descartes and Newton had imagined such as Maxwell's electrodynamics and Darwin's theory of evolution.

Nevertheless, the basic ideas underlying Newtonian physics, though sufficient to explain all natural phenomena, were still believed to be correct.

Radical change... paradigm shift... first three decades of twentieth century  The first three decades of the twenty-first century changed this situation radically. Two developments in physics, culminating in relativity theory and in quantum theory, shattered all the principal concepts of the  worldview of Descartes (Cartesian worldview) and the mechanical worldview of Newton (Newtonian mechanics). Doubts were raised about the  beliefs in the strictly mechanical view of nature, the separateness and pure objectivity of the observer or 'scientist', and the infallibility of induction as a theory-making process. In physics the  mechanistic paradigm had to be abandoned at the level of the very small – in atomic and subatomic physics – and the level of the very large - in astrophysics and cosmology. There followed a paradigm shift from the science of mechanics to the science of interconnectedness and wholeness or ‘holistic science’.

Implications for education

      

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  When he was twenty three years old laid the foundation for higher mathematics, celestial mechanics and physical optics. His method : combining deductive logic with reason he extracted a tentative premise - the hypothesis. The theory of gravitation - hypothesis - was tested with empirical observation.