According to the Theodicy of philosopher Gottfried Wilhelm Leibniz (1646–1716), describes any two objects if it is possible that they may simultaneously exist. Exported to the propositional case, two formulae $\phi$ and $\psi$ are compossible when it is possible that their conjunction is true. Formally, in a system with a possibility operator $♢$ and conjunction $\wedge$, that $\phi$ and $\psi$ are compossible is captured by the formula $♢\left(A\wedge B\right)$. Compossibility is a weaker notion than compatibility, that is, if two statements are compossible, they are compatible, although the converse does not necessarily hold. At times the binary connective of fusion has been regarded as capturing a notion of compossibility.