Unformatted text preview: guments
Unsound: An argument that has at least one false
Example: i. Cows are insects.
ii. Insects are mammals.
iii. So cows are mammals.
Example: i. All dogs have 5 legs.
ii. Fido is a dog.
iii. Therefore Fido has 5 legs Sound Arguments
Sound: An argument that is valid and contains
only TRUE premises
i. All cows are mammals.
ii. All mammals are animals.
iii. So cows are animals. Valid and Sound Arguments
All athletes are professional golfers T or F? Lebron James is an athlete T or F? Therefore, Lebron James is a professional golfer T or F? All humans are whales T or F? All whales are mammals T or F? So, all humans are mammals T or F? All Detroit Lions are football players T or F? Calvin Johnson is a football players T or F? Therefore, Calvin Johnson is a Detroit Lion T or F? Inductive and
Reasoning Part 5: Deductive Reasoning A process of reasoning in which
we start with a general rule or conclusion and
look to see whether specific evidence
supports, or fits, that previously held belief Deductive Reasoning
1. What is the conclusion?
2. What evidence supports it?
3. Is that evidence logical?
If you can answer yes to question 3, then the
conclusion should be logical and the
argument valid and sound.
Many deductive arguments are valid Click to View Video on YouTube Inductive Reasoning A process of reasoning in which we use small,
specific examples or observation to reach a BIG,
general rule, conclusion or theory Inductive Reasoning
When detectives arrive at the scene of a crime, the
first thing they do is look for clues that can help them
piece together what happened.
1. What have you observed? What evidence is
2. What can you conclude from that evidence?
3. Is that conclusion logical?
Many Inductive arguments are strong but invalid Click to View Video on YouTube Inductive or Deductive
Inductive: Evidence Deductive: Conclusion Conclusion (IEC) Evidence (DCE) Inductive or Deductive
If the truth of the premises does not definitely
establishes the truth of the conclusion, but provides
a strong reason to believe the conclusion true, then
you have an inductive argument
If the truth of the premises definitely establishes
the truth of the conclusion then you have a valid
deductive argument Inductive or Deductive
1. The Giants have lost their last seven games. Thus, they will
probably lose their next game. 2. If you brush and floss your teeth daily then you will have
fewer cavities. Marie brushes and flosses her teeth daily.
Thus, she will have fewer cavities. 3. Jones will play tennis today if Smith plays. Jones will not
play tennis today. Therefore, Smith will not play. 4. 4 out of 5 times I beat Corey at pool and I'm going to play
him tomorrow. So, I'll very likely win.
5. No man has ever gotten pregnant. Therefore, no man ever
will get pregnant. Inductive or Deductive
1. The Giants have lost …Inductive argument – uses 7 specific
examples to reach a bigger conclusion
2. If you brush and floss your teeth …Deductive argument – states
the broadly accepted research and reaches a specific conclusion
3. Jones will play tennis today if …Deductive argument –gives an
overarching rule that governs the behavior to predict a specific
4. 4 out of 5 times I beat Corey…Inductive argument – uses
specific examples to predict the conclusion
5. No man has ever gotten pregnant…Inductive argument – the
conclusion is a BIG, overarching rule based on numerous specific
examples to date. More Practice Here...
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This document was uploaded on 02/26/2014 for the course PHILOSOPHY 1101 at Douglas College.
- Winter '14