Explain, using a concrete example, why we should not allow the following inference when using $\textbf{ EG. }$ What restriction then is required on the use of $\textbf{ EG? }$

Question

Explain, using a concrete example, why we should not allow the following inference when using $\textbf{     EG.     }$ What restriction then is required on the use of $\textbf{    EG?     }$

Quizplus · Accepted Answer

The Answer is It could allow us to move from a true statement to a false one. For example, if Lxy = "x loves y", from the fact that someone loves someone it does not follow that anyone loves him or herself. EG requires that the variable that comes to be existentially quantified be one that does not already occur free in the formula we are quantifying.

Explain, Using a Concrete Example, Why We Should Not Allow EG. \textbf{ EG. } EG.

Explain, Using a Concrete Example, Why We Should Not Allow $\textbf{ EG. }$