Greek Philosophy and the Sensory Mind

Even today, nearly 2,500 years later, Greek philosophy is still revered, studied, and considered to hold fundamental truths.  Even though the Greeks are also known for launching numerous other disciplines such as engineering, mathematics, biology, chemistry, and physics to name a few, ….why is Philosophy the one that endures as still being cutting edge?  All of the other scientific disciplines keep advancing in their knowledge and sophistication.  However, with Philosophy it is different. 

Philosophy is different because the Greek philosophers were looking at the fundamental truths about Life and nature from which we came. The left-brain had a vantage point never again to be had.  The Greek philosophers were close to and had a clear view of the developing human mind without the subsequent huge build-up of left brain group think that has steadily developed since then.

The Greeks were uncovering totally new territory.  They were able to explore this virgin territory unencumbered by subsequent discoveries and evolutionary mind development.  They were certainly closer to the core of operation of the left brain and its emergence from right brain rule than anyone today could possibly be.  They could observe and describe a virgin condition.  Greek philosophy is still a standard bearer today.

Greek philosophy is best represented by the teacher/student big three of Socrates (470 BCE-399 BCE), Plato (427 BCE-347 BCE), and Aristotle (384 BCE–322 BCE). 

Socrates was obviously a great mind and thinker. He was a great public orator, teacher, and influencer of people.  He did not write anything, however, and left that to Plato. Socrates also riled the powers of the time which led to him drinking the hemlock juice.

The writings of Plato provide an amazingly clear view inside the human mind of 2500 years ago.  Plato’s greatest contribution is the Republic, and the best known passages are those of the Allegory of the Cave and the Analogy of the Divided Line. 

Plato’s Allegory of the Cave and the Analogy of the Divided Line each provide an introspective description of the vision-based right and the speech-based left portions of our mind.

Allegory of the Cave

In the Allegory of the Cave, Plato describes a Cave inhabited by a group of prisoners who face a wall inside the cave.  Behind them is a huge fire and between them and the fire is a raised walkway on which people carry forms made of wood, stone and other material.  The prisoners watch the shadows on the wall and are unaware of the forms that are casting the shadows. 

Figure. An illustration of Plato’s Allegory of the Cave.
Image from Lawrence, Matt. Like a Splinter in Your Mind. Mass.: Blackwell, 2004. p. 4. Illustration © Scott Mayhew


According to Plato, the shadows on the wall are as close as the prisoners can come to reality. The shapes of the shadows are ever-changing and illusory whereas reality is contained in the forms that cast the shadows.  According to Plato, we are those prisoners, trapped in a world of illusory images.  The prisoners accept the shadows as reality in the world because it is all they have ever known. 

The world of shadows is the world of vision.  Plato even states that the prison house is the world of sight.  With vision, shapes are continuously changing.  For example, think of a table.  The table can be viewed from a multiplicity of angles, and from each angle the table looks different; exactly as the shadows keep changing.  However, in reality there is a single real table that is casting the shadows.  The knowledge of the reality of that table is contained in our speech-based left brain.  We give the table a name and know that it exists.

Plato continues the analogy by freeing one of the prisoners from the cave and describes the difficult adaptation this freed prisoner would have to the new world of reality to which he is exposed.  This freed prisoner becomes enlightened by an entire new sense of reality.  Plato likens this journey out of the cave as “the ascent of the soul into the intellectual world”.

The Cave is the visual world of illusions from which we were imprisoned and from which we came.  We emerged into the intellectual world of the speech-based mind.  According to Plato, we can only know reality in the speech-based world.

Analogy of the Divided Line

In the Analogy of the Divided Line Plato begins the discussion by stating there are 2 ruling powers and that one of them is set over the intellectual world and the other over the visible world.  This analogy to our right and left brains could not be any clearer.

Plato further asks us to imagine a line that has been divided into 2 parts; he states that the 2 parts of the line represent the sphere of the visible and the sphere of the intelligible.  The sphere of the visible is the world that surrounds us.  It is a world of change and uncertainty and is filled with illusions and beliefs.  Consistent with the Allegory of the Cave, we cannot know reality in this world; we can only have opinions.  In the sphere of the intelligible, however, we have the unchanging products of human reason and intelligence.  This is the world of reality in which we can have true knowledge.

Plato further divides each of the 2 line segments into 2 divisions.  Each sphere is essentially divided into a lower and an upper region.  These lower and upper regions essentially refer to lower and higher levels of cognitive development in the 2 spheres.

Visible sphere: The lower level is comprised of images that are shadows and illusions.  The upper region contains everything that we see including animals, other forms of life, and man-made items.

Intelligible sphere: The lower level is comprised of hypotheses and ideas; the upper level is comprised of principles and knowledge. 

In these writings, Plato clearly differentiates our vision-based and speech-based minds.  He also establishes lower and higher levels of development of both sides.