 Hintikka and Sandu (1989) took up the task of formulating an explicit unified formal treatment for the different varieties of informational independence in natural language semantics. They posed the question of which are the mechanisms that allow English to exceed the expressive power of \(\mathbf{FO}\). For, natural languages typically do not resort to higher-order quantifiers. Hintikka and Sandu suggested that informational independence plays a key role in increasing the expressive power of natural  languages.[91]