7.2.5 Universal elimination

Another easy one:

$$\begin{fitch*} \par n & \forall x A \\ \par \hline \par & A\{t/x\} & E$\forall$\ n,t \par \end{fitch*}$$

If we know that $A$ always holds for any element, then we can select an element (anyone) and we also know that $A$ is true on that element.