idea

This is an essay on science I found interesting written by Junichiro Hashimoto（橋元淳一郎）:

Science obviously has a practical side.  It has brought material wealth into human civilization.  The true purpose of science, however, is not the pursuit of material wealth.  It is to seek what truly exists, and it derives from the ancient Greek philosophy.

Plato tells us a very intriguing story in his book The Republic:  In a long narrow cave, there are some prisoners who have been locked in a pillory since birth.  Because of the pillory, they can only see the wall of the cave; they have never seen the world behind their back.  Behind them, there is a little stage where a puppet show goes on.  Even further behind the stage near the entrance of the cave is a bonfire.  The shadows of the puppet reflect on the walls.

The prisoners who have only seen the walls their entire life, believe that the moving shadows are the only existence in the world.  To them, the only reality is the shadows.  However, if one of the prisoners were unlocked from the pillory and was allowed to look behind, he will see the puppets on the stage and probably be astonished.  The scene would be unbelievable to him, but if he hasn't lost his reason, he would realize that what he had believed was reality had only been the shadows of the puppets.  He will know that the puppets they could not see up until then was true existence, and that what they always saw had only been an illusion.

After telling us the story, Plato says that the prisoners are nothing but us humans, and that what we see in everyday life is only the shadows of what truly exists.

Plato called this true existence 'idea（イデア）'.  He says that idea is never to be seen, but without it, this world (which is its shadows) will not exist.  This can never be proved and thus, Plato's idea is nothing but an armchair theory.  If you can not prove it, it is not science.

However, to regard that only perceptible or verifiable things are the truth only brings us down to being one of the prisoners locked in a pillory.  This universe is not as simple as it seems.  It is natural to think that the truth lies beyond human experience and comprehension.

Lately it is said that this world is not three but ten dimentional, which means we can not "see" seven dimentions.  It is also said that 96% of space is an unknown existence, namely dark matter and dark energy.

The true purpose of science is not only to explain the mechanism of what we can see, but to unlock the pillory we tend to lock oursleves in without knowing it.

(Translated and edited by me)