If it is wrong to discriminate against women on the basis of gender, then it is wrong to
discriminate against men on the basis of gender.
Premise: It is wrong to discriminate against women
Implicit Premise: Men are equal to women
Conclusion: Therefore, it is wrong to discriminate against men as well.
Stealing is wrong. Using a friend's car without asking permission is taking property
without permission. So, using a friend's car without asking is wrong.
Premise: Stealing is wrong
Premise: Using a friend's car without asking is taking property without permission.
Implicit premise: Taking property without permission is stealing
Conclusion: Therefore, taking a friend's car without asking is wrong.
There are two questions that must be considered when we evaluate a deductive
1) Does the conclusion follow from the premises?
2) Should the premises be accepted as true?
Testing for validity only considers the answer to the first question
How do deductive arguments work?
like analyzing math problems
Premise: John has 16 cows = 16
Premise: Jill sold two of John's cows: -2
Premise: Jack gave 6 cows to John: +6
Conclusion: John has 20 cows
Mathematical and Logical Reasoning
A: Subject Matter Independence
B: Arguments contain different structural parts
C: Context clues and common sense to correctly identify the structure of 'natural
Statements or propositions
In logic, information can be represented by variables
In order to represent a statement with a variable, it must be a meaningful
statement that is either true or false
Jack has a horse (j) = good
Jack has (h) = bad 1) Assign one unique letter to each meaningful statement.
2) Assign the same variable to 2 statements that 'mean' the same thing
Jack has a pig (p)
Jack has a mammal (m)
A mammal does Jack have (m)
Jack owns a mammal (?)
4 basic connectives of putting pieces of information together
I have a turtle and a fish
Therefore, I have a fish
I have a turtle. Therefore, I have a fish.
------ : The truth of the premises does not imply the truth of the
Jack and Jill are going to the party. Therefore, Jack will go to the party.
Valid J & I
--------- : Premises imply conclusion.