Explain Plato's and Aristotle's ideas of form, body, knowledge and soul.

Plato had located the universal essence of things in the Forms which lay beyond the physical realm. In contrast, Aristotle argued that these Forms could be identified on the basis of inductive arguments based on observation in the physical realm. Just as Plato had, Aristotle faced the problem of identifying continuity of being (essence) in an ever-changing world. Plato considered the physical realm to be less than perfect (it was always changing), which is why he located perfection elsewhere. However Aristotle believed the physical realm was not imperfect so he looked for explanations around him. In doing so he began to conclude that the physical realm, despite always being in flux, moves towards specific ends. In this sense the physical realm demonstrates a certain teleology (telos = 'end' or 'purpose'). Furthermore, the essence of a thing did not lay outside the physical realm but was very much contained within it

To counter Plato's transcendent Forms Aristotle talked of categories. For example, one could speak of a large white elephant. Now the elements within this description are, 'large', white' and 'elephant'. However, Aristotle did not believe they had the same ontological status as each other. The terms 'large' and white' do not exist in the same way as an 'elephant' does. In fact, 'large' and 'white' are dependent on the term 'elephant' for their meaning. Thus we can say that here 'elephant' is the substance whilst 'large' and 'white' are merely qualities which do not exist on their own but only in relation to the subject ('elephant').

Although substance and quality are one of ten categories identified by Aristotle it is only substance which he believed underlined everything else. For instance, if there were no 'elephant' then is this instance 'large' and 'white' would have no relationship to it (i.e. without something there would be nothing else!).

Plato's belief of the body and soul are similar to his ideas about duality. He believed that the human body was made up of different components: the physical body, the mind and the immortal soul. The body, like everything else physical, is in a constant state of change, and therefore, cannot be the source or the object of reliable truth, because it is never the same from one moment to the next. The soul, in contrast, is immortal and unchanging, and as such, can both know and be known. Plato believes that the body is the physical component of each person. The body is the part that presents an appearance for others to see and hear. It is through the body that we receive our sense experiences, so that our minds are able to form our opinions and reasons. Our minds are also able to achieve and awareness of the eternal truths beyond the physical world, in the realm of ideas, or forms. All our senses are based in the body and are consequently unreliable. The soul is the realm of reason. And not being physical, the soul can survey the world of ideas.

Plato also believed that the soul existed before it inhabited the body. As soon as the soul wakes up in a human body, it has forgotten all the perfect ideas. Then a process begins. As the human being discovers the various forms in the natural world, a vague recollection stirs his soul. Plato calls this yearning eros- meaning love. The soul, then, experiences a 'longing to return to its true origin'. From now on, the body and the whole sensory world is experienced as imperfect and insignificant. The soul yearns to fly home on the wings of love to the world if ideas. It longs to be freed from the chains of the body.

Plato also believed that the mind and body are in opposition. The mind wants to understand ideas, to gain real knowledge of the forms; but the body is interested in sense pleasures, and it has its needs such as eating and sleeping which are constantly getting in the way of intellectual pursuits, because they keep interrupting. The soul, according to Plato is the directing force of the body.

According to Aristotle, every animate being is a living thing, which can move itself only because it has a soul. Animals and plants, along with human beings, are more like each other than any of them are like any inanimate object, since each of them has a soul.

All such beings, on Aristotle's view, have a nutritive soul, which initiates and guides their most basic functions, the absorption of food, growth, and reproduction of its kind. All animals (and perhaps some plants) also have a sensitive soul by means of which they perceive features of their surroundings and move in response to the stimuli this provides. Human beings also possess (in addition to the rest) a rational soul that permits representation and thought.

Notice that each living thing has just one soul, the actions of which exhibit some degree of nutritive, sensitive, and/or rational functioning. This soul is the formal, efficient, and final cause of the existence of the organism; only its material cause resides purely in the body. Thus, all of the operations of the organism are to be explained in terms of the functions of its soul.

Plato made two contributions to the theory of knowledge. One was that knowledge is recollecting what is in your head already, not perceiving new things. The other was his theory of forms.

Plato faced two major problems when he came to consider what true knowledge is. A philosophical problem; he has to reconcile the problem of One and the Many, and a human problem; he had to battle against the sophists.

Sophists were professional philosophers who lived in Athens at the time of Plato. They were sceptics, who believed that there was no such thing as certain knowledge. Plato spoke out against them. He believed that truth, not worldly success, was the proper aim of philosophy.

Plato's point is that we can never have true knowledge of anything that is in a constant state of change. We can only have opinions about things that belong to the world of the senses, tangible things. We can only have true knowledge of things that can be understood with our reason.

Reason is eternal and universal precisely because it only expresses eternal and universal states. Plato found mathematics very absorbing because mathematical states never change. They are therefore states we can have true knowledge of.

We can only have inexact conceptions of things we perceive with our senses. But we can have true knowledge of things we understand with out reason.

When it came to the theory of knowledge, Aristotle believed in three categories; sensation, thought and desire.

Sensation is the passive capacity for the soul to be changed through the contact of the associated body with external objects. In each variety of sensation, the normal operations of the appropriate organ of sense result in the soul's becoming potentially what the object is in actuality. Thus, without any necessary exchange of matter, the soul takes on the form of the object: when I feel the point of a pin, its shape makes an impression on my finger, conveying this form to my sensitive soul (resulting in information).

Thought is the more active process of engaging in the manipulation of forms without any contact with external objects at all. Thus, thinking is potentially independent of the objects of thought, from which it abstracts the form alone. Even the imagination, according to Aristotle, involves the operation of the common sense without stimulation by the sensory organs of the body. Hence, although all knowledge must begin with information acquired through the senses, its results are achieved by rational means. Transcending the sensory preoccupation with particulars, the soul employs the formal methods of logic to cognise the relationships among abstract forms.

Desire is the origin of movement toward some goal. Every animate being, to some degree, is capable of responding to its own internal states and those of its external environment in such a way as to alleviate the felt absence or lack of some pleasure or the felt presence of some pain. Even actions taken as a result of intellectual deliberation, Aristotle supposed, produce motion only through the collateral evocation of a concrete desire.

So in short, Aristotle says that knowledge is derived from the senses but it needs more than just that to succeed.

From looking at the information I have written about Plato and Aristotle's beliefs on the theory of forms, body, soul and knowledge we can see that both their ideas differ.

Aristotle had many criticisms of Plato's theory of forms.

He argued that, pushed to its logical conclusion, Plato's theory of forms appears slightly ridiculous. For Aristotle, knowledge is perception, therefore, if we did not perceive anything, we would not learn or understand anything, and whenever we think of anything, we must at the same time think of an idea. He believed that the natural world is the real world and that perception and sense-experience are the foundations of scientific knowledge.

For Plato the reality of the world is in the forms as understood by intellect. For Aristotle, the reality of the world is in 'matter', the stuff the world is made of.

Aristotle decided that all substances have two parts: material and structure- or 'matter' and 'form'. Matter and form belong to this world, not to a world bey9ond this world, like Plato's forms.

Plato started with the intellect; Aristotle started with perceptions of the natural world. Plato's understanding was mathematical- dealing in concepts which can be worked out without relation to the natural world; Aristotle's understanding was scientific, based on perception, observation and investigation.

Although both Plato and Aristotle are considered among the greatest philosophers, they had significant differences between their philosophies. Plato was more "other worldly" while Aristotle focused on concrete things in the world. Whilst Aristotle was intrigued by the concrete world, Plato wanted nothing to do with it. Plato believed that people know forms all along, whi8le Aristotle thought that people had the ability to abstract them from the objects themselves. Although they are quite different, it is still very interesting to read about them both.