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The Logically Sound Argument

The simple but not so easy process of constructing sound logical argument has been represented by Karl Albrecht in the table below. Of the combinations of true and false premises and valid and invalid arguments, only one lead you to a sound logical argument.

Premises + Argument = Conclusion*
If the Premises Are: And the Argument Is: Then the Proposition Is:
True Valid Sound
True Invalid Unsound
False Valid Unsound
False Invalid Unsound
Only one combination of premises and argument gives a sound logical argument.

If you listen carefully to the conclusions that people represent as sound, many rest on either false premises or invalid arguments. Listen carefully to what people tell you about economics. Get them to give you evidence of the truth of their premises in examine carefully the validity of their argument. If they have not combined true premises with a valid argument, you have every right to doubt the soundness of their conclusion.

One thing for which you have to remain wary consists of a sound conclusion supported by a combination of either false premises or invalid arguments. The soundness of the conclusion does not prove either the truth of the premises nor the validity of the argument. So be careful, just because the soundness of the conclusion can be demonstrated, to not apply this argument to a similar situation until you have checked out the truth of the premises in the validity of the arguments.

I will expand on this discussion later.

*Albrecht, Karl, Brain Power. New York: Simon & Schuster, 1980, page 165

Deductive Reasoning