Intro to Logic

   - Syllabus

   - Study Guide

   - Logic Book

   - Workbook

   - Links


  Intro to Philosophy  

   - Syllabus

   - Homework

   - Study Guide

   - Links

  Intro to Humanities

   - Syllabus

   - Homework

   - Study Guide

   - Links


Chapter:  INT  |  1  |  2  |  3  |  4  |  5  |  6  |  7  |  8  |  9  |  10  |  11  |  12  |  13 | 14

15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33


C H A P T E R  3







Skepticism was caused by:

1. The increase awareness of other cultures and their ideas

2. The decline in tradition, religion, and objective values.

3. Disagreements among philosophers

4. Democracy




Skepticism in Action

PROTAGORAS (About 490-420 BCE)

Protagoras by Plato


1.  We perceive the world indirectly.

2.  Perception, knowledge, truth, and values are subjective and relative.
     Objective knowledge is unattainable. (Skepticism)
     There are no objective values.
     Values are a matter of convention - not nature.

3.  "Man is the measure of all things ... ."  (relativism)
     (How should we interpret man?)

4.  The goal of life is success.
     True ideas are those that lead to success.

5.  The Sophists taught rhetoric.
     The goal of life and arguing is victory - not virtue or truth.






He was the first of the Sophists.

Although he was an agnostic, he said, "concerning the gods I am unable to discover whether they exist, ... " he thought that religion served an important purpose.






GORGIAS (483-375 BCE)

108 years old!

Gorgias by Plato



1.     True knowledge is unattainable.
        His skepticism was caused by the paradoxes of Zeno.
        Reason, language, and perception are inadequate for knowledge.

2.     We are trapped in a subjective world of our experiences.





1. We should reject traditions and laws, and satisfy our nature.

    Our nature is to seek our own advantage - and self-preservation.






know thyself
(From the temple of Apollo at Delphi)

(469–399 BCE)

Miles Burnyeat on Plato: Section 1




1.    His mother was a midwife.
       He was referred as a midwife of ideas.

2.    He and his father were sculptors.

3.    He had a wife and three kids.

4.    His teacher was the Sophist Prodicus.

5.    Socrates taught Plato.

       Plato's early dialogues represent the real Socrates.

6.    The Oracle of Delphi declared Socrates the wisest Man.
       Chaerephon posed the question.

4.    He was tried for corrupting the youth, and not believing in the Gods.

      At 70 years old he was executed by drinking hemlock.
      The Sophists lost their reputation because of Socrates.







1.    Know thyself.

       Your soul is your true self.

       An excellent soul is wise, virtuous, and temperate.

2.    I know only that I know nothing. (Academic Skepticism)

3.    Virtue is knowledge.

       People pursue their own good.

       Being virtuous is our own good.

      To know the good is to do the good. 

4.    All things have an essence.

       Essences can be expressed in essential definitions.

       What is X? What is justice is asked in Republic by Plato,

       virtue is explored in Plato's Meno, temperance is in the Charmides,

       love is in the Symposium, friendship the Lysis,

       the Laches explores courage, and the Euthyphro duscusses piety.

5.    Contract theory of state:


In Plato's dialog the Crito Socrates refuses to escape from jail. The fact that he willingly remained in Athens, means that he accepted their laws. He cannot violate them when they are used against him.


Plato's dialogue the Apology is the trail and conviction of Socrates. In that dialogue, Socrates says that he would refuse to stop doing philosophy:



And therefore if you let me go now, and are not convinced by Anytus, ... and that if I escape now, your sons will all be utterly ruined by listening to my words—if you say to me, Socrates, this time we will not mind Anytus, and you shall be let off, but upon one condition, that you are not to enquire and speculate in this way any more, and that if you are caught doing so again you shall die;—if this was the condition on which you let me go, I should reply: Men of Athens, I honor and love you; but I shall obey God rather than you, and while I have life and strength I shall never cease from the practice and teaching of philosophy, exhorting any one whom I meet and saying to him after my manner: You, my friend,—a citizen of the great and mighty and wise city of Athens,—are you not ashamed of heaping up the greatest amount of money and honor and reputation, and caring so little about wisdom and truth and the greatest improvement of the soul, which you never regard or heed at all? And if the person with whom I am arguing, says: Yes, but I do care; then I do not leave him or let him go at once; but I proceed to interrogate and examine and cross-examine him, and if I think that he has no virtue in him, but only says that he has, I reproach him with undervaluing the greater, and overvaluing the less. And I shall repeat the same words to every one whom I meet, young and old, citizen and alien, but especially to the citizens, inasmuch as they are my brethren. For know that this is the command of God; and I believe that no greater good has ever happened in the state than my service to the God. For I do nothing but go about persuading you all, old and young alike, not to take thought for your persons or your properties, but first and chiefly to care about the greatest improvement of the soul. I tell you that virtue is not given by money, but that from virtue comes money and every other good of man, public as well as private. This is my teaching, and if this is the doctrine which corrupts the youth, I am a mischievous person. But if any one says that this is not my teaching, he is speaking an untruth. Wherefore, O men of Athens, I say to you, do as Anytus bids or not as Anytus bids, and either acquit me or not; but whichever you do, understand that I shall never alter my ways, not even if I have to die many times.




The Great Dialogues of Plato




Republic by Plato


1.     Justice is the interest of the strong - the golden rule:
        He who has the most gold makes all the rules.        

2.     To be just is to obey the laws of those in power.

3.     The powerful make mistakes.

4.     The powerful can make laws that are not in their interest.

5.     To obey these laws is not in the interest of the strong; therefore

6.     to be just is to do what is, and is not, in the interest of the strong.




1.  Power-brokers may make laws that aren't in their interest.

2.  Obeying such laws isn't in their interest; therefore

3.  being just is to do what is in the interest of the strong - and not to do what is in the interest of the strong.

4. The Sophists contradict themselves; they say there are no objective truths. Truth is relative, and all opinions are equal. At the same time they say that their position is better and true.










Copyright © 2010