Both philosophers have their ideas on what is ideal. Reason is at the core of their teachings. In René Descartes' Meditations on First Philosophy, he enumerated six meditations which served as the threshold of modern Western philosophy.
In it, Descartes discusses several of Aristotelian doctrines and questions its basic principles such as the necessity of senses to our thinking. Descartes examines the Aristotelian concept that all knowledge stems from the senses and that mental states merely resemble them. Descartes did not agree with this view. He believes that perceptions from the senses are unreliable and that reasoning by the deduction is the right method to arrive at the right conclusion.
Descartes began his Meditations with the idea of skepticism. Then, he slowly showed the importance of recognizing senses and imagination as part of the mental processes. Descartes made a controversial claim that the mind and body do not have anything in common. He arrived at this conclusion by observing that our mind is made to think and the body merely extends our thoughts.
A number of philosophers support Descartes ideas but his theory on the mind-body link is still controversial even to this day. A number of advocates of mind-body link believe that the mind greatly affects the body as opposed to Descartes separate function of mind and body and that the one could not affect the other.
His view on religion is equally thought-provoking. He believes the perception of God is innate, which means it was there by the time we were born and must be put there by a Higher Being. Descartes just like Plato believes in the presence of God, a benevolent God, as he termed it.
Since God is benevolent, then we can rely on the reality our senses provide us because God provided us with a mind and senses that do not deceive us. This argument could be seen as flawed and subject to contention but through this, Descartes firmly established the concept of acquiring knowledge through the use of senses or perception and deduction. That reason could be the only way to attain knowledge.
Descartes idea of Utopian society would probably be one where the improvement of thinking, senses and imagination or, the mental faculties is encouraged. Being a rationalist, Descartes believe that clarity of perceptions of the mind is the best way to gain knowledge. The information derived from the senses merely helps us to live in a practical manner.
Utopia is based mostly on Plato's Republic. In The Republic, Plato expounds on his idea of an idea society. The society is basically characterized by an abundance of equality and a general pacifist attitude. The citizens are however ready to wage battle should the need arise. Poverty and misery are non-existent. Laws are reduced to the basics. There are no lawyers. Citizens do not need to go to war. Instead mercenaries from neighboring states are hired in the hope that they would be extinguished in their missions thus reducing the evils in the world.
Plato's Utopia is a religious one. In The Republic, Plato expounds his belief in the Form of the Good which actually pertains to God. He compares the Form of the Good to the sun. He says that just as the sun radiates light, so the form of the good radiates truth. Plato believes that the highest form of knowledge is the form of the good, from which all things that are considered just derives their worth. Humans are bounded by duty to find the good, but no one can hope to achieve this without philosophical reasoning.
Plato and Descartes seem to agree that there is a need to search for reasons in order to reach the highest good or attain deeper spirituality. Just like Descartes, Plato believes that in order to arrive at the right conclusion, humans have to travel from perception to reason and understanding.
The things that we perceive are actually mere shadows of the walls. True reality is the ideas in our mind and the form of Good which is God.
Plato's arguments have religious bent on them unlike Descartes who sees reasoning as an end in itself. Plato sees reasoning as a means to arrive at the end which is enlightenment and God.
Plato's Allegory of the Cave, Metaphor of the Sun and Analogy of the Divided Line in The Republic captured the essence of this view. The particular and the concrete are not the ultimate real forms in Plato's intellectual world which is represented by the general and the abstract. The particular and the concrete then are just mere representations of the general and the abstract. They bore only a striking resemblance of the ultimate reality found in the intellectual world.
The metaphor for particular and the concrete is shadows of cut-out shapes found on the walls of the cave which are mere symbols of the truth outside the cave lighted up by the sun.
In the “divided line”, “allegory of the cave” and the “image of the sun”, Plato discusses the metaphysics that divides the world into two separate aspects: the intellectual world of “forms”, and the visible or perceptual world we see around us. The visible world comprises of imperfect copies of the intellectual world of forms or ideas. These forms are unalterable and perfect. These can only be understood by the use of the intellect or understanding such as using that part of the mind that does not include sense-perception or imagination.
Plato's account of reality affirms the need to recognize the fact that reality is not what we see alone. Reality is much more than that. Reason, imagination and spiritual values form another part of reality that is as real and undeniable as those we see or perceive through our senses.
At the top this intellectual world is the Good, which shines down on all. Next is the form, the perfect versions of earthly objects which we remember when we see the objects. The forms provide us with our understanding, knowledge, and intelligence. We understand or know a horse because of the memory of the form horse. Next lowest is reason or thought based on axioms.
Then we cross the divider in the line, the visible things to which the other side of the line is applied. At the top of this lower section is belief, or perception based ideation. Next is the imagination.
One of the aspects in the intellectual world is reason. At the top of the ladder is the Good, followed by Form then Reason. The reason or thought is based on axioms. The reality statis of mathematical entities for Plato is that mathematical principles fall under Reason because they are too perfect to be considered part of the visible world.
