 Avicenna is quick to point out that neither general nor special absolute sentences behave as expected. For example, they do not fit the traditional square of opposition. ‘Every B is A’ on the general reading does not contradict ‘Some B is not A’. Thus, he introduces one other kind of absolute sentence, namely a perpetual absolute sentence. In a perpetual sentence the copula is simply read as ‘is always’. The contradictory of a general absolute is the perpetual absolute, and similarly with the special absolute, although it will contradict a disjunction of two perpetual sentences (see Street 2002 and Lagerlund 2009). 