Lecture 3: Deductive and Inductive Arguments.

“I would rather write 10,000 notes than a single letter of the alphabet.” ― Ludwig van Beethoven

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A group is riding on a train and talks among themselves. At some point, one member of the group is coming up with a conclusion. The chain to that conclusion seems correct. The conclusion based on premises that also all the group agrees. By itself, the argument is well built. But something went wrong along the way.

In some member minds and their understanding of the world, it can’t be true.

It was a deductive argument based on Inductive premises. In other words, the conclusion was based on stereotypes.

Deductive

let’s look at the Following arguments:

Premises 1: Socrates is a man

Premises 2: All men are mortal

Conclusion: Socrates is mortal

We want to look at the lines of the conclusion. We call them “Implied lines”.

We will call it a good argument, due to the strongly implied arrow. In other words, it’s a deductive argument. We conclude something from the whole group and always right to the specific man, Socrates.

Given the premises is correct. The conclusion is Always certain, then it’s deductive.

Inductive

Premises 1: Socrates is in jail

Premises 2: people in jail usually has broken the low

Conclusion: Socrates broke the low

This implication here is not that strong as in deductive. It’s more like a probable cause.

This is an Inductive argument

Given the premises is correct. The conclusion is probably true then it’s inductive.

Stereotypes

Stereotypes are inductive arguments. You do know something about the group, It can be because you met a few. And you drawing your conclusion about the whole group.

For example,

Premises 1: Frank is Native.

Premises 2: All Natives are Strong.

Conclusion: Frank is Strong.

We can see the premises 2 is the stereotype. It’s the result of an inductive argument that was made years ago.

The argument “as is” is deductive.

The audience needs to understand that “premise 2” comes from inductive. So, the result is must be also an inductive argument. meaning:

Frank could be strong.

See how the second conclusion is less powerful.

Why is the confusion?

1. People want to show their argument as stronger
2. The speaker truly believe that premise 2 is correct

How to tell people they are wrong

Most people will get offended if you will tell that they are wrong. The best way to tell people that are willing to listen is to show what premise is correct. That the conclusion is correct if it actually correct. But, where the error happened. This way the speaker could rephrase the argument and try again.

Indicator words

premises:

1. Because — pay attention it’s not an explanation
2. Given
3. Since
4. In view of

Conclusion:

1. It follows that
2. Therefor
3. Thus
4. So — In case it doesn’t use like: “that is so great”
5. Hence
6. Consequently

Deductive

1. Must
2. Always

Inductive

1. might
2. fairly to believe

Exceptions

However, But, Still — Doesn’t belong to any of the categories. They indicate that a switch is going to happen in the argument.

Unfortunately — Show our feeling about the issue. This type of words is softening the conclusion or the premise.

This is my “lecture 3” notes. The lecture from Fayetteville State University’s Critical Thinking class.
lecturer: Dr. Sadler
https://youtu.be/VbeD20mTTRk