Plato's Theaetetus

In Plato's Theaetetus Plato attempts to show what knowledge is. Socrates asks Theaetetus what he thinks knowledge is. Since Theaetetus answers incorrectly, Socrates presents other definitions about knowledge. One theory is "Man is the Measure of all things." Although this theory comes from Socrates, he still believes it is in need of more explanation. Socrates reverts to Protagoras' teachings and explains his theory on the idea that "Man in the Measure of all things"

Socrates presents Protagoras' revised version of the theory that "Man is the Measure of all things" Protagoras' theory states that each man is the measure of truth. According to this, nobody is superior to anyone else and we all are equal in truth. However, some men are wiser because their opinions are more beneficial than those of others. The wise hold beliefs that are beneficial and try to convince others that it's beneficial. For example, professors use their ability to teach others and persuade them to see as they see or at least to challenge their teachings. Protagoras explains, through the use of words, he has the ability to change people's appearance. Protagoras concludes that "Man is the Measure of all things" is true.

Protagoras' revised theory is much stronger than the old theory. In the old theory, Socrates explains that man determines what is truth and false. What appears to someone is what it is to him, and what appears to someone else is what it is for that person. Socrates says this is identical to the idea that knowledge is perception. Since perceiving is identical to appearing, then whatever one sees, feels or smells is true. If that is correct, then man is always right and truth changes as man's perception changes. After many objections of this old theory, Socrates concludes that knowledge is not perception. Man cannot be the measure of all things because everyone perceives things differently and things are not always the way they seem. The old theory was simply refuted because perception is easily altered.

In continuing the conversation with Theodorus and Theaetetus, Socrates presents many objections to Protagoras' revised version of the theory. His two most powerful objections are the fact that Protagoras' theory contradicts itself and how knowledge cannot be perception. According to Socrates, Protagoras is wrong "in conceding the truth of the opinion of those who think he's wrong, he is really admitting the falsity of his own opinion" (171b). If the theory states that each of us judges that is truth and falsity, Protagoras must then admit that if some people believe his own theory is false, then they are right. Socrates asks "supposing [Protagoras] himself did not believe that man is the measure, any more than the majority of people (who indeed do not believe it) then this Truth which he wrote is true for no one?" (170d). when someone believes that man is not the measure of all things, then that man is right; therefore, Protagoras must say this is true due to his theory. The consequence of Protagoras' theory is that it is false, and it only takes one person to disagree with it to make it false, for that person.

According to Protagoras, knowledge and perception are equivalent. If this is true, then anyone who perceives a foreign language, he knows what is being said. Even if the person has never learned the language, he can still understand it. In reality, this is not true. One does not understand a foreign language without first learning it. When we hear a foreign language, we do not understand it and therefore, knowledge is not perception. Protagoras' theory is easily refuted due to his ideas being merely substantial.

Although Protagoras' theory is condensed due to him being unavailable, one can still recognize the objections given by Socrates are suitable. These objections are most significant because they give clear and precise examples that most anyone can relate to. Each objective given can speak for itself and make Protagoras' theory false. More detail and thinking is involved in order to argue perfectly that "Man is the Measure of all things".

3. In Plato's Theaetetus, Socrates and Protagoras are both presented as teachers. Socrates claims that he practices the art of midwifery. On the other hand, Protagoras declares his work as a teacher involves "changing the appearances" (166d). These two styles of teaching involve different methods of acquiring the truth. Both "arts" require different conceptions of what truth is.

Socrates' style of midwifery is very deliberate and not just anyone can practice it. Characteristics of being a midwife include the ability to match couples up for marriage who will produce the best offspring; the power to bring pain and give relief; the power to know who is pregnant and who isn't; and the ability