<p>Quine famously proposed to represent the intuitive ‘vast difference’ between the notional and the relational reading of the indefinite noun phrase occurring in a belief report of the form “S believes that a P is Q” in terms of the different scope of the existential quantifier, thereby assimilating the intuitive distinction to the theoretical distinction between <i>de dicto</i> and <i>de re</i> interpretation of belief reports. After having highlighted the substantial identity between the notional/relational distinction and the distinction between epistemically nonspecific and specific reading of indefinites in a belief report, the paper addresses two problems. The first is whether the Quinean representation is materially adequate; a negative answer is motivated through the analysis of a famous argument apparently entailing the collapse between <i>de dicto</i> and <i>de re</i> interpretation of belief reports. The second problem is how to represent the ‘vast difference’; the answer that is proposed is based on the adoption of an intuitionistic semantics for first order logic.</p>