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Understanding Logic (Simplified- Again)

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Anoud Abusalim

on 11 November 2017

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Transcript of Understanding Logic (Simplified- Again)

Understanding Logic
(Simplified- Again)
WRI 102

What is logic?
Logic is a formal system of analysis that helps writers invent, demonstrate, and prove arguments. It works by testing propositions against one another to determine their accuracy. People often think they are using logic when they avoid emotion or make arguments based on their common sense, such as "Everyone should look out for their own self interests" or "People have the right to be free." However, unemotional or common sense statements are not always equivalent to logical statements. To be logical, a proposition must be tested within a logical sequence.

Let's Watch this opening video
Now, we are talking Syllogism
The most famous logical sequence, called the syllogism, was developed by the Greek philosopher Aristotle. His most famous syllogism is:
Premise 1: All men are mortal.
Premise 2: Socrates is a man.
Conclusion: Therefore, Socrates is mortal.
In this sequence, premise 2 is tested against premise 1 to reach the logical conclusion. Within this system, if both premises are considered
, there is no other logical conclusion than determining that Socrates is a mortal.

Logical Vocabulary
: Proposition used as evidence in an argument.
: Logical result of the relationship between the premises. Conclusions serve as the thesis of the argument.
: The assertion of a conclusion based on logical premises.
: The simplest sequence of logical premises and conclusions, devised by Aristotle.
: A shortened syllogism which omits the first premise, allowing the audience to fill it in. For example, "Socrates is mortal because he is a human" is an enthymeme which leaves out the premise "All humans are mortal."
: A process through which the premises provide some basis for the conclusion.
: A process through which the premises provide conclusive proof for the conclusion.

Deductive Reasoning
Deductive reasoning involves drawing conclusions from specific statements that are called premises.
All apples are fruits.
: A granny smith is an apple.
Therefore, a granny smith is a fruit.

According to the first premise, all items that are classified as apples are also classified as fruits.
According to the second premise granny smith is classified as an apple. The first premise is a general statement, while the second premise refers to a specific case.
The conclusion says that a granny smith has to be a fruit, because of its inherent properties as an apple.
This deductive argument is also valid, which means that the conclusion necessarily follows from the premises.

Some History
Some Fun Patrice
1- Using the white boards, write two arguments that use deductive logic.
2- The team that produces two true and valid arguments first will get five bonus points
3-No use of the internet is allowed
4-This activity is 3 minutes only.
Truth and Validity
: All dogs have long ears.
: Puddles is a dog.
: Therefore, Puddles has long ears.

Given the premises that all dogs have long ears and Puddles is a dog it is logical to assume that Puddles has long ears. After all, in this example, long ears are an inherent quality of dogs. This argument is valid. Does it mean that it is also true?

Not all dogs have long ears. Certain breeds, like Yorkies or Pugs, have small ears.
Because the conclusions are based off the premises and one of the premises is not true, it follows that the conclusion is not true, even though it is valid. You can see from this example that if one of the premises is not true, the conclusion is also not true.

Inductive Reasoning
Inductive Reasoning, involves going from a series of specific cases to a general statement. The conclusion in an inductive argument is never guaranteed.
: This cat is black.
That cat is black
A third cat is black.
: Therefore all cats are are black.

Two-thirds of my latino neighbors are illegal immigrants.
Therefore, two-thirds of latino immigrants come illegally.

Fun Patrice Two
1- Using the white boards, write two arguments that use deductive logic.
2- The team that produces two true and valid arguments first will get five bonus points
3-No use of the internet is allowed
4-This activity is 3 minutes only.
Deduction and induction by themselves are inadequate to make a compelling argument. While deduction gives absolute proof, it never makes contact with the real world, there is no place for observation or experimentation, no way to test the validity of the premises. And, while induction is driven by observation, it never approaches actual proof of a theory. Therefore an effective paper will include both types of logic. 1
Final Thoughts
Logical Fallacies
P. 75 Where I Stand
Errors Affecting the Truth:
Avoiding the issue
Double Standards
Shifting the Burden of Truth
Irrational Appeal

Let's get ready for your argumentative essay by checking the prompt in week 12 folder.
Full transcript