3.2 Contingent sentences

Sentences like $(p\rightarrow q) \rightarrow p$, parenthesized THIS way, are called contingent sentences, They are sometimes true and sometimes false.

$$\begin{array}[t]{l} \fbox{ \begin{array}[t]{@{}\vert c\vert ... ...athrm{\:T\:} & \mathrm{\:F\:}\\ \hline \end{array}}\end{array}$$

Another example:

$$\begin{array}[t]{\vert c\vert c\vert c\vert\vert c\vert c\ve... ...rm{\:F\:}& \mathrm{\:T\:} &\mathrm{\:T\:}\\ \hline \end{array}$$