Common Sense

"Common sense is the collection of prejudices acquired by age eighteen"  Albert Einstein

“Common sense is not so common.”  Voltaire, A Pocket Philosophical Dictionary

“Nowadays most people die of a sort of creeping common sense, and discover when it is too late that the only things one never regrets are one's mistakes.” Oscar Wilde, The Picture of Dorian Gray

“The three great essentials to achieve anything worthwhile are, first, hard work; second, stick-to-itiveness; third, common sense.” Thomas A. Edison 

“It is the obvious which is so difficult to see most of the time. People say 'It's as plain as the nose on your face.' But how much of the nose on your face can you see, unless someone holds a mirror up to you?” Isaac Asimov, I, Robot

“Common sense is the most widely shared commodity in the world, for every man is convinced that he is well supplied with it.” René Descartes  

“A long habit of not thinking a thing wrong, gives it a superficial appearance of being right, and raises at first a formidable outcry in defense of custom. But the tumult soon subsides. Time makes more converts than reason.”  Thomas Paine, Common Sense

“Common sense ain't common.” Will Rogers

“Common sense is seeing things as they are; and doing things as they ought to be.” Harriet Beecher Stowe

 “The cradle rocks above an abyss, and common sense tells us that our existence is but a brief crack of light between two eternities of darkness.” Vladimir Nabokov

Common sense is defined by Merriam-Webster as, "sound and prudent judgment based on a simple perception of the situation or facts."    The Cambridge Dictionary defines it as, "the basic level of practical knowledge and judgment that we all need to help us live in a reasonable and safe way".

I don't believe that common sense exists.  I tend to agree with Einstein's and Roger's definitions.  I find comments such as "He may have book sense but he doesn't have common sense" places the recipients of those comments into defined boxes rather attempting to understanding the complexities that exists in all of us.

Common sense keeps us from asking what if, challenging the status quo, and restricts our imagination.  My case in point is the parallel postulate.  The parallel postulate, also called Euclid's fifth postulate because it is the fifth postulate in Euclid's Elements.  It states that, in two-dimensional geometry:  If a line segment intersects two straight lines forming two interior angles on the same side that sum to less than two right angles, then the two lines, if extended indefinitely, meet on that side on which the angles sum to less than two right angles.  Probably the best known equivalent of Euclid's parallel postulate is Playfair's axiom, named after the Scotsman John Playfair, which states:  At most one line can be drawn through any point not on a given line parallel to the given line in a plane.

Two mathematicians, Nikolai Lobachevsky and János Bolyai, created two geometries, hyperbolic and elliptic, by challenging the notion of the parallel postulate.  The discovery of these alternative geometries that may correspond to the structure of the universe helped to free mathematicians to study abstract concepts irrespective of any possible connection with the physical world.  

 

We build, construct, and teach an Euclidean world and in a local view that is true.  A global view does have longitudinal lines intersecting the equator at 90° angles but intersecting at the poles forming triangles whose interior angles exceed the sum of 180°.  An universe view may point to a hyperbolic geometry.

An attorney friend mentions me in most of his closing arguments as the disbeliever of common sense.  I think he pleads the jurors to apply theirs.  A colleague commented on her shock that the parallel lines she was taught do not exist on our globe.  Perhaps common sense is not so common nor should it be.