 Grice captures the role of moods in specifying meaning by introducing a special notation. He represents the indicative case this way: \(U\) means that \(\vdash\)(the door is closed); the imperative: \(U\) means that !(the door is closed). Here ‘the door is closed’ represents a moodless, underlying syntactical element Grice calls a sentence radical; it designates the moodless proposition that the door is closed. Grice calls ‘\(\vdash\)’ and ‘!’ mood operators, and he explains them contextually as follows: