 In modal first-order logic, the difference between de re and de dicto is given by  the scope of the involved quantifiers and modal operators.  On the one hand, a de dicto (“of the proposition”) sentence indicates a property of a proposition, with the involved quantifier occurring under the scope of modalities. For example, the de dicto reading of the previous sentence is given by the formula \(\oBox\left(\exists x (x = s(f) \land x &gt; 2) \right)\) (with s a function returning its parameter’s number of sisters). On the other hand, a de re (“of the thing”) sentence indicates a property of an object, with the involved modality occurring under the scope of quantifiers. For example, the de re reading of the previous sentence is given by the formula \(\exists x \left( x = s(f) \land \oBox(x &gt; 2) \right)\). This crucial distinction can be exemplified by the difference between some agent i knowing that there is someone that makes her Happy (but maybe without knowing who this person is), \(K_i\exists x H(x, i)\), and the always preferred existence of someone who i knows makes her happy \((\exists x K_i H(x, i))\).