Invalid Argument/Examples/Moon is Yellow

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Example of Invalid Argument

This argument is invalid:

The moon is yellow.
Therefore, the moon is made of cheese.


Proof

Let $P$ denote the simple statement The moon is yellow..

Let $Q$ denote the simple statement The moon is made of cheese..


The argument can then be expressed as:

\(\text {(1)}: \quad\) \(\ds P\) \(\) \(\ds \)
\(\text {(2)}: \quad\) \(\ds \therefore \ \ \) \(\ds Q\) \(\) \(\ds \)


There is nothing connecting the two statements.

Hence this is not a valid argument form.

$\blacksquare$


Sources