Chapter 9 - Theoretically Speaking

Chapter 9 - Theoretically Speaking

 

Spiritual prophets allow one to see the light.  Einstein allowed mankind to see beyond the light.

                     

 

In today’s world, we are used to hearing the term modelling; the modelling indicates this, or the modelling shows that.   The general public feeds hungrily on such trite phrases and pseudo-information, thrown at them by a flood of people using jargon and long overblown words.  Such people sought out by the media and politicians for their opinions, must be, by default, like it or not, unquestionably regarded as experts.

 

On hearing the word �" modelling - we routinely think of computer modelling; however, modelling takes many forms.  One may construct a physical scale model, be it landscape or buildings �" model the economy, based on spreadsheets and graphs �" model fashion �" or design an accurate computer simulation; conversely, an attempt can be made to construct a larger predictive model, based on known data and human conjecture.  Without wishing to enter a contentious terrestrial area of debate �" the current, so-called, climate science debate, is a most obvious example.  The current computer predictive models being used are constantly updated as additional valid data becomes available; fine-tuning to reflect the continually unfolding reality.  This tinkering does not render computer modelling useless, quite the contrary; using the latest technology gives modern scientists an edge never before experienced in history.  However, as with all science and things scientific, such modelling must always be open to challenge; rather than be treated as the absolute truth �" or as politicians are too fond of saying:  settled science.

 

Throughout history, one of the more fascinating types of modelling has been, mental modelling, more popularly known as the thought experiment.  Adapted accordingly, thought experiments have served a number of disciplines, most frequently philosophy, science and physics. 

 

 

Such experiments may be described as being a form of mental exercise, carried out to consider a hypothesis or opinion; the aim in science or physics, being to determine the probable consequences of the theory in question.  No matter how one describes the method there can be no denying its importance in bringing about conceptual change in science.

 

One of the earliest examples of a thought experiment dates back to Lucretius (99 BC-55 BC).  Attempts were made at that time to demonstrate that space is infinite:  If there was a supposed limit to the universe, a spear could be tossed at it.  If the spear flew through, no such limit existed; if the spear bounced back, there must be something beyond the hypothetical limit of space �" a cosmic wall that stopped the spear �" a wall that is space itself.  Either way there is no limit to space; thus space is infinite.  The logic is beautiful in its simplicity and, understandably, beyond practical testing.  Nevertheless, the example serves to demonstrate the deductive power that allows the thinker to step outside the ‘square of reality’.

 

Galileo is recognised as a key character in the progression of thought experimentation into its modern form.  He is responsible for the ‘mathematization’ required in creating an idealized illustration, and then linking that illustration back to the real world.  Whilst that might sound a bit vague �" one must consider how all thought experiments �" after undergoing the mental processes of the experimenter - are then described to the world at large in a narrative form.  The translation to story form makes the concept under discussion more acceptable and apparent, even to the uninitiated.  For example, consider how Galileo asked that two different sized objects made of the same material, be dropped from a height.  He then supposed the two objects be ‘tied together’ �" with a thin, almost immaterial string (notice the intricate detail).  Galileo then indicates the two objects must fall both faster and slower, than as individual objects.  The two should fall faster, he stated, because the body has now become heavier: and should fall slower because the slower object should retard the motion of the faster (or heavier) object.   What Galileo elegantly exposed with his thought experiment were the discrepancies and uncertainties surrounding medieval thinking in regard to the differences in the speed of falling bodies, in relation to their weight. 

Incidentally �" on July 26^th, 1971, astronauts on the Apollo 15 Moon mission carried out this same experiment using a hammer and a feather, on the surface of the Moon. http://www.youtube.com/watch?v=5C5_dOEyAfk

 

In a later chapter, I specify two examples of thought experiments; those being Schrodinger’s cat and Maxwell’s demon.   Those of course are two of the more well-known modern paradoxical examples of such experiments.  Considering those experiments, I began to wonder exactly how such experiments actually featured in Einstein’s work, and how they so convincingly came together to present such an uncannily correct set of data.

 

Allegedly, Einstein’s papers on Special Relativity grew from a thought experiment, performed when he was only 16 years old.   Autobiographical notes recall how Einstein once daydreamed about chasing a beam of light as it sped through the universe.  He thought if he were able to fly next to the beam of light, at the speed of light, he should be able to watch the light frozen in space as an ‘electro-magnetic field at rest though spatially oscillating.’  Sic

 

I find such vivid living detail in a daydream quite revealing in itself.  For Albert Einstein, at least, the thought experiment proved that for his imaginary observer - ‘everything would have to happen according to the same laws as for an observer who, relative to the Earth, was at rest.’

 

In yet another thought experiment, Einstein asked that we thought about a magnet and a conductor in relative motion.  There are two possible methods by which a current might be produced.  First, the magnet is at rest and the conductor is moving; according to electromagnetic theory, the motion of the conductor through the magnetic field produces and electromotive force that creates a current in the conductor.  In the second case; the conductor is at rest and the magnet is moving.   Again, according to the theory, the motion of the magnet creates a changing magnetic field that induces an electric field, which in turn induces a current in the conductor.  However, with respect to the relative motions, it makes no difference whether it is the magnet or the conductor that is to be considered to be in motion. 

Whilst it is beyond the scope of this chapter to go into the detail of such results �" suffice to say the results did not correspond to earlier conclusions reached by one James Clerk Maxwell.  Certain elements of Maxwell’s Equations relied upon the concept of the aether and consequently, took the effects of the elusive aether into account on reaching conclusions and developing his famous equations.   In the course of his thought experiments, Einstein rejected the aether as needless and predicted the existence of a fixed speed of light, independent of the speed of the observer.

 

History records that Maxwell’s equations were an essential component in the development of Einstein’s paper on Special Relativity.  However, in the opening paragraph of his paper Einstein refers to the thought experiment relating to the magnet and conductor in support of his own hypothesis - as opposed to Maxwell’s conclusions.

 

One thing seems certain; all thought experiments contain common features.  As noted above, by the time it is related to the community the thought experiment is in a narrative form; no matter how bizarre the situation might be in its presentation!  The assumption is that the experiment could be executed, and the chain of events would take place as in the real world.  Any thought experiment symbolizes explicit suggestions concerning the hypothesis under investigation, and exposes contradictions or reveals paradoxes that arise under a variety of applied circumstances.  By the time it is presented to the world at large, the experiment always works and is often more convincing than most real world experiments.  Rarely do we get to see the failed thought experiments �" which probably far outnumber successful ones.

 

 Being in a narrative form, abstractions from real world experiences are possible.  Certain features that would occur naturally can be removed including the colours of surroundings or the physical characteristics of an observer.  The scene is always pre-set according to the needs of the experiment.  There may be a need to include some quite intricate details to reinforce vital aspects of the experiment.  In one version of Einstein’s chest or elevator experiment, Einstein even depicts the physicist as being drugged and then awakening in the container. 

That point underpins the necessity for the observer being rendered unaware of the environment in which the experiment is taking place �" thereby maintaining the integrity of the experiment. 

 

Human imaginative prowess has been central to the development of scientific thought.  Without human curiosity and the questions: “What if” or “Why” we might still be at a very primitive scientific and technological level.  Certainly, in our own time, the formation of such deep abstractions as quantum mechanics would be most unlikely without the primary role played by the thought experiment.  Can computer modelling or simulation replace �" the thought experiment? 

My feeling is definitely: NO.  Computers are too restrictive, whereas, human imagination knows no bounds.  Nevertheless, I see no reason why one day, computing power will not widen our options in unravelling the mysteries of the universe and further augment the already fertile human imagination. 

Refs:

Brown, J. R. (1996, December 29). Thought Experiments. Retrieved September 4, 2011, from Stanford Encyclopedia of Philosophy: http://plato.stanford.edu/entries/thought-experiment/#ComFeaThoExp

Fowler, M. (2009). Galileo and Einstein. Retrieved June 2, 2011, from Uva Dept of Physics: http://galileoandeinstein.physics.virginia.edu/

Jupiter Publishing. (1997). The Bible According to Einstein . New York: Jupiter Scientific Publishing Company.

Nersessian, N. Why Do Thought Experiments Work. Princetown New Jersey: Princetown University.

Norton, J. D. (2005, February 15). Chasing a beam of light: Einstein's most famous thought experiment. Retrieved September 4, 2011, from John D Norton: http://www.pitt.edu/~jdnorton/Goodies/Chasing_the_light/

Wikipedia. (2011, August 25). Maxwell's equations. Retrieved September 5, 2011, from Wikipedia the Free Encyclopedia: http://en.wikipedia.org/wiki/Maxwell's_equations#A_Dynamical_Theory_of_the_Electromagnetic_Field

Wikipedia. (2011). Thought Experiment. Retrieved September 3, 2011, from Wikipedia the Free Encyclopedia: http://en.wikipedia.org/wiki/Thought_experiment