 For the next clauses, recall that the symbol, “\(\rightarrow\)”, is an analogue of the English “if … then … ” construction. If one knows, or assumes \((\theta \rightarrow \psi)\) and also knows, or assumes \(\theta\), then one can conclude \(\psi\). Conversely, if one deduces \(\psi\) from an assumption \(\theta\), then one can conclude that \((\theta \rightarrow \psi)\).