- Applying logical rules to your premises until only the truthful conclusion remains
- Intends to provide conclusive support for its conclusion
- When providing conclusive support for its conclusion, it is valid
- When not providing conclusive support for its conclusion, it is invalid
- Validity is all or nothing
- If premises provided are true, the conclusion must be true (certain)
- Are premises true?
- Do the premises lead to this conclusion?
- True premises aren't enough (must be valid)
- Gasoline is poison (true)
- Bleach is poison (true)
- Conclusion: gasoline is bleach (false)
- Deductively valid arguments with true premises are sound
- Valid arguments are not necessarily true (sound)!
- Unjustly killing innocent people is wrong
- THe holocaust was a case of unjustly killing innocent people
- Conclusion: Holocaust was wrong