example of valid and invalid arguments in logic?

Question

please give me an example of
1. a valid argument with one TRUE premise and one FALSE premise, and a FALSE conclusion
2. one true, one false and a TRUE conclusion

Answer 1

1. PR1: Alligators are reptiles. <--- true premise

PR2: All reptiles wear boots. <---- false premise

Therefore,

Conc: Alligators wear boots <---- false conclusion



1 is a valid argument.



2. PR1: Blueberries exist. <---- true premise

PR2: Anything that exists is the color blue<--- false premise

Therefore,

Conc: Blueberries are the color blue. <---- true conclusion





2 is also a valid argument.





edit: to the guy below... how is it true that turtles are mammals? do you know what true means? He's asking for a true conclusion in the second example. Not a false one.

Answer 2

Invalid Argument Examples

Answer 3

I hate to bring politics into this, but I've heard this one so many times it's the first example to come to mind of an invalid conclusion based on true premises:



- America has been at war in Iraq since March 2003.

- There have been no successful Muslim terrorist attacks on American soil during that time.

- Therefore, the war prevented terrorist attacks.



The problem with this "logic" is that there is no proof of any causal relationship between the first two statements. A valid logical conclusion requires at least one if-then statement. In reality the changes in airport security may have been a much stronger deterrent.



Brian's examples of TRUE-FALSE-FALSE and TRUE-FALSE-TRUE arguments are better than the ones I thought of, but I wanted to give an example of invalid logic. His are both logically valid arguments even though one results in a false conclusion due to a false premise.

Answer 4

This Site Might Help You.



RE:

example of valid and invalid arguments in logic?

please give me an example of

1. a valid argument with one TRUE premise and one FALSE premise, and a FALSE conclusion

2. one true, one false and a TRUE conclusion

Answer 5

I'm not sure... but does this help a bit?



2

- If the street is wet, it has rained. (false, it could be due to a leaking garden hose, idk)

- The street is wet. (true)

+ Thus it had rained.

Answer 6

look up logical fallacies in wikipedia