Chapter's 3 & 4 SynopsisByMark Childers PHIL 1381 June 4, 2005 Chapters 3 & 4 Synopsis I believe the assumption of an external reality is the assumption that there is a real world that is external to our mind and senses, and that it exists whether or not we as observers exist, and whether or not we are observing it. This assumption cannot be proved because all of our perceptions, without exception, are mental images, and we have no means to go beyond our mental images. It is one we all commonly make without even thinking about it. In the military, we assume the office and the computer in it are there after we leave work at the end of the day and will be there when we arrive at work in the morning. When we head home at the end of the day, we assume that our house or apartment will be there when we arrive, and that it continued to be there in our absence after we left in the morning. We assume that our friends, relatives, and acquaintances are there whether we can see and talk to them or not, and whether or not we are thinking about them.

We assume that our parents existed before we were born, and that many of the people we know will be alive after we die. So many of our everyday experiences repeatedly confirm this assumption that most of us hardly question it. It is an assumption that has enormous survival value: we know that a speeding car can kill us while we are crossing the street absorbed in our thoughts and unaware, that a stray bullet can instantly obliterate our consciousness without warning, or that we can die from an external agent such as a virus, a bacterium, or a poison. The assumption of external reality is necessary for science to function and to flourish. For the most part, science is the discovering and explaining of the external world.

Without this assumption, there would be only the thoughts and images of our own mind (which would be the only existing mind) and there would be no need of science, or anything else. In addition to the assumption of an external reality, we also make the assumption that this reality is objective. This is repeatedly confirmed by our daily experience as well as by scientific observations. I also learned that objectivity means that observations, experiments, or measurements by one person can be made by another person, who will obtain the same or similar results.

The second person will be able to confirm that the results are the same or similar by consultation with the first person. Hence, communication is essential to objectivity. In fact, an observation that is not communicated and agreed upon is not generally accepted as a valid observation of objective reality. Because agreement is required, objective reality is sometimes called consensus reality. We have said that science assumes that external reality exists whether or not it is observed but that this cannot be proved since all of our observations are necessarily purely mental images. A statement that by its very nature cannot be proved is not a physical assumption, but is called a metaphysical assumption.

(Such an assumption can also be called an axiom.) Thus, the bedrock of all science is not science at all but is metaphysics! Not only the nature of science, but also our experience of living, would be fundamentally changed if this assumption were not made. Idealism states that mind or consciousness constitutes the fundamental reality, or is primary. Some versions of idealism admit the existence of material objects, others deny that material objects exist independently of human perception. Plato is often considered the first idealist philosopher, chiefly because of his metaphysical doctrine of Forms. Plato considered the universal Idea or Form, sometimes called an archetype -- for example, redness or goodness -- more real than a particular expression of the form -- a red object or a good deed.

According to Plato, the world of changing experience is unreal, and the Idea or Form -- which does not change and which can be known only by reason -- constitutes true reality. Plato did not recognize mystical experience as a route to true reality, only reason. Idealism was first expounded by Plato in his cave allegory in The Republic. Prisoners are in an underground cave with a fire behind them, bound so they can see only the shadows on the wall in front of them, cast by puppets manipulated behind them. They think that this is all there is to see; if released from their bonds and forced to turn around to the fire and the puppets, they become bewildered and are happier left in their original state.

They are even angry with anyone who tries to tell them how pitiful their position is. Only a few can bear to realize that the shadows are only shadows cast by the puppets; and they begin the journey of liberation that leads past the fire and right out of the cave into the real world. At first they are dazzled there, and can bear to see real objects only in reflection and indirectly, but then they look at them directly in the light of the sun, and can even look at the sun itself. (Chapter 4), Descartes most important influences were his classical education in the works of Plato and Aristotle, and the teachings of the Roman Catholic faith. The Platonist influence clearly shows in his writings in Meditations, especially in his ideas of archetypes. He felt that these archetypes represented ultimate ideas -- the purest forms ideas, which would give rise to all ideas similar to them.

This concept is similar in nature, if not in exact application, to Plato's forms. His Roman Catholic influences are better demonstrated in his struggling attempt to work God into his philosophy as the ultimate idea, akin to Plato's Form of the Good. Descartes contemporaries fell into two camps. All respected the man for intelligence and his contributions to other fields of science, but they typically either liked him a great deal or did not care for him or his teachings. Among his chief detractors were Thomas Hobbes and the Scholastics, followers of the Aristotelian methods of science. Descartes did not endear himself to his critics at all.

He had an arrogant attitude about him, and at one point wrote a letter to Diet, the Provincial in charge of the Jesuits of Paris, saying there is not a solution proposed by Aristotelian thinking he cannot prove false. Descartes' disagreements with Hobbes were more philosophical in nature, basically resolving into child-like disputes over whose methods were better, Descartes espousing his idealism and mind-matter dualism, Hobbes clinging to his materialistic thought. However, even his supporters were not immune to his criticisms, and he was not above supporting his detractors when he agreed with them. Along with Hobbes and Galileo, among others, Descartes wished to eliminate some of the major Aristotelian components of modern thought.

To Morin, a supporter of Descartes and an instructor at the school at Sorbonne, he writes that the school uses comparisons akin to '... explaining corporeal things by intellectual things, or essentially comparing apples to oranges. He goes on to say that his comparisons are better because he compares only those things which are alike.