The document summarizes the key philosophers Socrates, Plato, and Aristotle and their foundational contributions to Western philosophy and logic. It discusses that Socrates developed the Socratic method of questioning beliefs to develop ideas. Plato was Socrates' student and founded The Academy, while Aristotle studied almost every topic and founded his own school, the Lyceum. Aristotle is noted for developing logical thinking through rules like syllogisms and the scientific method.

1. Who Defined the Study of
Philosophy and Logic?
• Socrates, Plato and Aristotle
• These three philosophers form the basis of
what is known as Western Philosophy
• Every thinker and scientist that followed
used their methods

2. Socrates
b. 470 BCE
• Developed the Socratic method:
• A series of questions are used to examine beliefs and develop
ideas.
• “The unexamined life is not worth living.”
• “ There is only one good, knowledge, and one
evil, ignorance.”
• “Know thyself.”
• Was executed in Athens after being convicted of
corrupting the youth with his ideas.

3. Plato
b. 428 BCE
• Was Socrates’ brilliant student
• Traveled extensively before returning to teach at
The Academy.
• Allegory of the Cave- the real world is only a
reflection of the truth, of a higher reality
• He believed that the perfect political system would
feature “philosopher kings” as it rulers, people
versed in ethics and who truly loved only one
thing: truth and knowledge

4. Aristotle
b. 384 BCE
• Plato’s student
• Aristotle studied almost every single topic from
anatomy to economics to geography, physics,
politics, psychology, religion, and even poetry.
• He founded his own school after leaving the
Academy, and his center of knowledge became
known as the Lyceum.
• Was Alexander the Great’s personal teacher.

5. Aristotle Part 2
• Developed a vast system of rules for logical
thinking to define the world.
• Much like a game has rules, so, too, must logic
• Syllogism def. If A=B and B=C, then A=C
• Causality: If I set fire to a piece of paper (cause)
then it will burn (effect).
• Scientific Method:
• 1. Observe and take notes
• 2. Make a theory
• 3. Test the theory

6. What is Logic?
• Def. logic is the study of the rules for correct, or valid,
reasoning.
• Deduction: Reasoning that moves from the general to the specific. It is
a form of inference where if the premises are true, the conclusion must
also be true.
– All humans have two legs, the major premise,
– I am a human, the minor premise, therefore,
– I have two legs, the conclusion.
• Induction: Reasoning that typically moves from specific examples to a
larger, general observation. If the premises are true, then the conclusion
probably is true.
– '95 households out of 100 have a TV. I am going to stay
with Fred, so I will probably be able to watch TVquot;.

7. What are the unstated
assumptions?
• I failed that course because the instructor didn’t like me.
Assumption: The instructor fails students he doesn’t like.
• I’m not surprised he made the team. After all, his father is the
superintendent of schools.
Assumption: The superintendent gives special favors to his family
• If I’d only taken my boss to lunch more often, I could have gotten that
raise.
Assumption: The boss denies raises to people who don’t take him to
lunch very often.
Analyze the assumptions behind every idea!!!

8. What is a syllogism?
• a specific method of logical deduction
(moving from the general to the particular)
every syllogism contains at least three parts:
– a major premise (global assumption)
– a minor premise (specific claim)
– a conclusion
• It’s kind of like simple math
If A = B and B = C, then A = C

9. A visual representation
all things with hair
all mammals have hair
mammals
fish do not have hair
fish
Fish are not mammals

10. True vs. Valid Arguments
• True argument = an argument with a conclusion
that is considered factually correct.
• Valid argument = an argument with a
conclusion that makes sense logically, regardless
of whether it is true or not.

11. True, Valid or Both?
All old people are bad drivers.
bad drivers
Old people
Jean is an old person.
Jean
Jean is a bad driver.
If the premises are true,
the conclusion would be true.
So this is a valid argument, but obviously false.

12. True, Valid, or Both
• All fruits have seeds.
• Tomatoes have seeds.
• Therefore, a tomato is a fruit.
Scientifically, this is valid and true
All fruits
Tomatoes

13. Is this True, Valid, or Both?
• No human being is immortal.
• God is not a human being.
• Therefore, God is immortal.
human Faulty logic because this
beings syllogism assumes anything not
all things immortal human is immortal. However,
according to many people’s
beliefs, this is a true statement:
God So this is an invalid argument,
but a true conclusion.

14. Is this True, Valid, or Both?
• All weeds are plants.
• A flower is a plant.
• Therefore, all weeds are flowers.
plants
The conclusion here does not
logically follow as a
flowers necessary consequence;
weeds therefore this argument is
invalid.