 As an example, consider a simplification of Ramsey’s toy theory that states that being at a blue location with open eyes is followed by being at a red location with open eyes: \(\forall x(Bx \wedge Ox \to Rx' \wedge Ox')\), where \(x'\) is the successor of \(x\). ‘Blue’ (\(B\)), ‘red’ (\(R\)), and ‘open eyes’ (\(O\)) are theoretical terms. The correspondence rules define the observational terms ‘perceiving blue’ as ‘being at a blue location with open eyes’, \(\forall x(Px \leftrightarrow Bx \wedge Ox)\), and correspondingly ‘perceiving red’ \(\forall x(Qx \leftrightarrow Rx \wedge Ox)\). The Ramsey sentence of \(TC\) is then: