Is the argument below valid? Announcing the arrival of Valued Associate #679: Cesar Manara Planned maintenance scheduled April 17/18, 2019 at 00:00UTC (8:00pm US/Eastern) Which kinds of Philosophy.SE questions should be taken from (or tolerated in)…How does one contradiction in argument makes the argument valid?In formal logic, how is it possible for an argument with a contradictory conclusion to be valid?The validity of the definition of a valid argumentWhy is this argument valid?Is this a valid argument?Determine if an argument is valid or invalidConcerning the definition of “valid”What is the difference between a conditional and material implication?How is “~A. Therefore A -> B” a valid argument?Is this argument valid?
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Is the argument below valid?
Announcing the arrival of Valued Associate #679: Cesar Manara
Planned maintenance scheduled April 17/18, 2019 at 00:00UTC (8:00pm US/Eastern)
Which kinds of Philosophy.SE questions should be taken from (or tolerated in)…How does one contradiction in argument makes the argument valid?In formal logic, how is it possible for an argument with a contradictory conclusion to be valid?The validity of the definition of a valid argumentWhy is this argument valid?Is this a valid argument?Determine if an argument is valid or invalidConcerning the definition of “valid”What is the difference between a conditional and material implication?How is “~A. Therefore A -> B” a valid argument?Is this argument valid?
If interest rates go down, then I will buy a house. If I buy a house, I will need
a loan. Therefore, I will not need a loan if I do not buy a house.
Is this argument valid?
logic
New contributor
Bruce Grayton Toodeep Muzawazi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |
If interest rates go down, then I will buy a house. If I buy a house, I will need
a loan. Therefore, I will not need a loan if I do not buy a house.
Is this argument valid?
logic
New contributor
Bruce Grayton Toodeep Muzawazi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
I made an edit. You may roll this back if it does not represent your view by clicking on the "edited" link above my image and then on a rollback link. Welcome!
– Frank Hubeny
5 hours ago
add a comment |
If interest rates go down, then I will buy a house. If I buy a house, I will need
a loan. Therefore, I will not need a loan if I do not buy a house.
Is this argument valid?
logic
New contributor
Bruce Grayton Toodeep Muzawazi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
If interest rates go down, then I will buy a house. If I buy a house, I will need
a loan. Therefore, I will not need a loan if I do not buy a house.
Is this argument valid?
logic
logic
New contributor
Bruce Grayton Toodeep Muzawazi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Bruce Grayton Toodeep Muzawazi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 5 hours ago
Frank Hubeny
10.4k51558
10.4k51558
New contributor
Bruce Grayton Toodeep Muzawazi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 5 hours ago
Bruce Grayton Toodeep MuzawaziBruce Grayton Toodeep Muzawazi
61
61
New contributor
Bruce Grayton Toodeep Muzawazi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Bruce Grayton Toodeep Muzawazi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Bruce Grayton Toodeep Muzawazi is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
I made an edit. You may roll this back if it does not represent your view by clicking on the "edited" link above my image and then on a rollback link. Welcome!
– Frank Hubeny
5 hours ago
add a comment |
I made an edit. You may roll this back if it does not represent your view by clicking on the "edited" link above my image and then on a rollback link. Welcome!
– Frank Hubeny
5 hours ago
I made an edit. You may roll this back if it does not represent your view by clicking on the "edited" link above my image and then on a rollback link. Welcome!
– Frank Hubeny
5 hours ago
I made an edit. You may roll this back if it does not represent your view by clicking on the "edited" link above my image and then on a rollback link. Welcome!
– Frank Hubeny
5 hours ago
add a comment |
2 Answers
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Is the argument valid?
No.
"I will not need a loan if I do not buy a house" is the same as "If I do not buy a house, then I will not need a loan".
This is not implied by "If I buy a house, I will need a loan".
See Denying the antecedent.
add a comment |
Wikipedia describes validity as follows:
In logic, an argument is valid if and only if it takes a form that makes it impossible for the premises to be true and the conclusion nevertheless to be false.
The argument we want to test for validity is the following:
If interest rates go down, then I will buy a house. If I buy a house, I will need a loan. Therefore, I will not need a loan if I do not buy a house.
This can be broken up into propositions with this symbolization key:
- R: "Interest rates go down."
- B: "I will buy a house."
- L: "I will need a loan."
If R then B. If B then L. Therefore, if not B then not L.
We could place the following into a truth table generator. For the truth table generator I am using I would enter the following string:
((R=>B)&&(B=>L))=>(~B=>~L)
This is the result I get:

Note the "F" in the third line of the table. This is a line where the premises are true but the conclusion false. Therefore the argument is invalid.
Stanford Truth Table Tool http://web.stanford.edu/class/cs103/tools/truth-table-tool/
Wikipedia contributors. (2019, March 28). Validity (logic). In Wikipedia, The Free Encyclopedia. Retrieved 18:05, April 15, 2019, from https://en.wikipedia.org/w/index.php?title=Validity_(logic)&oldid=889899195
add a comment |
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2 Answers
2
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2 Answers
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Is the argument valid?
No.
"I will not need a loan if I do not buy a house" is the same as "If I do not buy a house, then I will not need a loan".
This is not implied by "If I buy a house, I will need a loan".
See Denying the antecedent.
add a comment |
Is the argument valid?
No.
"I will not need a loan if I do not buy a house" is the same as "If I do not buy a house, then I will not need a loan".
This is not implied by "If I buy a house, I will need a loan".
See Denying the antecedent.
add a comment |
Is the argument valid?
No.
"I will not need a loan if I do not buy a house" is the same as "If I do not buy a house, then I will not need a loan".
This is not implied by "If I buy a house, I will need a loan".
See Denying the antecedent.
Is the argument valid?
No.
"I will not need a loan if I do not buy a house" is the same as "If I do not buy a house, then I will not need a loan".
This is not implied by "If I buy a house, I will need a loan".
See Denying the antecedent.
answered 4 hours ago
Mauro ALLEGRANZAMauro ALLEGRANZA
29.7k22065
29.7k22065
add a comment |
add a comment |
Wikipedia describes validity as follows:
In logic, an argument is valid if and only if it takes a form that makes it impossible for the premises to be true and the conclusion nevertheless to be false.
The argument we want to test for validity is the following:
If interest rates go down, then I will buy a house. If I buy a house, I will need a loan. Therefore, I will not need a loan if I do not buy a house.
This can be broken up into propositions with this symbolization key:
- R: "Interest rates go down."
- B: "I will buy a house."
- L: "I will need a loan."
If R then B. If B then L. Therefore, if not B then not L.
We could place the following into a truth table generator. For the truth table generator I am using I would enter the following string:
((R=>B)&&(B=>L))=>(~B=>~L)
This is the result I get:

Note the "F" in the third line of the table. This is a line where the premises are true but the conclusion false. Therefore the argument is invalid.
Stanford Truth Table Tool http://web.stanford.edu/class/cs103/tools/truth-table-tool/
Wikipedia contributors. (2019, March 28). Validity (logic). In Wikipedia, The Free Encyclopedia. Retrieved 18:05, April 15, 2019, from https://en.wikipedia.org/w/index.php?title=Validity_(logic)&oldid=889899195
add a comment |
Wikipedia describes validity as follows:
In logic, an argument is valid if and only if it takes a form that makes it impossible for the premises to be true and the conclusion nevertheless to be false.
The argument we want to test for validity is the following:
If interest rates go down, then I will buy a house. If I buy a house, I will need a loan. Therefore, I will not need a loan if I do not buy a house.
This can be broken up into propositions with this symbolization key:
- R: "Interest rates go down."
- B: "I will buy a house."
- L: "I will need a loan."
If R then B. If B then L. Therefore, if not B then not L.
We could place the following into a truth table generator. For the truth table generator I am using I would enter the following string:
((R=>B)&&(B=>L))=>(~B=>~L)
This is the result I get:

Note the "F" in the third line of the table. This is a line where the premises are true but the conclusion false. Therefore the argument is invalid.
Stanford Truth Table Tool http://web.stanford.edu/class/cs103/tools/truth-table-tool/
Wikipedia contributors. (2019, March 28). Validity (logic). In Wikipedia, The Free Encyclopedia. Retrieved 18:05, April 15, 2019, from https://en.wikipedia.org/w/index.php?title=Validity_(logic)&oldid=889899195
add a comment |
Wikipedia describes validity as follows:
In logic, an argument is valid if and only if it takes a form that makes it impossible for the premises to be true and the conclusion nevertheless to be false.
The argument we want to test for validity is the following:
If interest rates go down, then I will buy a house. If I buy a house, I will need a loan. Therefore, I will not need a loan if I do not buy a house.
This can be broken up into propositions with this symbolization key:
- R: "Interest rates go down."
- B: "I will buy a house."
- L: "I will need a loan."
If R then B. If B then L. Therefore, if not B then not L.
We could place the following into a truth table generator. For the truth table generator I am using I would enter the following string:
((R=>B)&&(B=>L))=>(~B=>~L)
This is the result I get:

Note the "F" in the third line of the table. This is a line where the premises are true but the conclusion false. Therefore the argument is invalid.
Stanford Truth Table Tool http://web.stanford.edu/class/cs103/tools/truth-table-tool/
Wikipedia contributors. (2019, March 28). Validity (logic). In Wikipedia, The Free Encyclopedia. Retrieved 18:05, April 15, 2019, from https://en.wikipedia.org/w/index.php?title=Validity_(logic)&oldid=889899195
Wikipedia describes validity as follows:
In logic, an argument is valid if and only if it takes a form that makes it impossible for the premises to be true and the conclusion nevertheless to be false.
The argument we want to test for validity is the following:
If interest rates go down, then I will buy a house. If I buy a house, I will need a loan. Therefore, I will not need a loan if I do not buy a house.
This can be broken up into propositions with this symbolization key:
- R: "Interest rates go down."
- B: "I will buy a house."
- L: "I will need a loan."
If R then B. If B then L. Therefore, if not B then not L.
We could place the following into a truth table generator. For the truth table generator I am using I would enter the following string:
((R=>B)&&(B=>L))=>(~B=>~L)
This is the result I get:

Note the "F" in the third line of the table. This is a line where the premises are true but the conclusion false. Therefore the argument is invalid.
Stanford Truth Table Tool http://web.stanford.edu/class/cs103/tools/truth-table-tool/
Wikipedia contributors. (2019, March 28). Validity (logic). In Wikipedia, The Free Encyclopedia. Retrieved 18:05, April 15, 2019, from https://en.wikipedia.org/w/index.php?title=Validity_(logic)&oldid=889899195
answered 4 hours ago
Frank HubenyFrank Hubeny
10.4k51558
10.4k51558
add a comment |
add a comment |
Bruce Grayton Toodeep Muzawazi is a new contributor. Be nice, and check out our Code of Conduct.
Bruce Grayton Toodeep Muzawazi is a new contributor. Be nice, and check out our Code of Conduct.
Bruce Grayton Toodeep Muzawazi is a new contributor. Be nice, and check out our Code of Conduct.
Bruce Grayton Toodeep Muzawazi is a new contributor. Be nice, and check out our Code of Conduct.
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I made an edit. You may roll this back if it does not represent your view by clicking on the "edited" link above my image and then on a rollback link. Welcome!
– Frank Hubeny
5 hours ago