Unsound Deductive Argument

An unsound deductive argument is a deductive argument that is an unsound argument (that leads to a false conclusion).

• Context:
  • It can (often) have a False Premise.
  • ...
• Example(s):
  • Some organisms with wings can fly. Penguins have wings. Therefore, penguins can fly..
  • ...
  • …
• Counter-Example(s):
  • a Sound Deductive Argument.
  • a True Premise.
• See: False Belief, Invalid Argument.

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References

2011a

• (Wikipedia, 2011) ⇒ http://en.wikipedia.org/wiki/Argument#Soundness
  • A sound argument is a valid argument with true premises. A sound argument, being both valid and having true premises, must have a true conclusion. Some authors (especially in earlier literature) use the term sound as synonymous with valid.

2011b

• (Wikipedia, 2011) ⇒ http://en.wikipedia.org/wiki/Soundness
  • In mathematical logic, a logical system has the soundness property if and only if its inference rules prove only formulas that are valid with respect to its semantics. In most cases, this comes down to its rules having the property of preserving truth, but this is not the case in general. ... An argument is sound if and only if: 1) The argument is valid. 2) All of its premises are true. For instance: All men are mortal; Socrates is a man; Therefore, Socrates is mortal.

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