 As sketched earlier, the truth of such existence claims as ‘there are tables’ and ‘there are unicorns’, which are expressed within the framework for observable entities, is to be determined empirically, since empirical observations and investigations are needed. These statements are not true in virtue of the rules of the language. By contrast, existence claims such as ‘there are numbers’ (‘\(\exists xNx\)’) expressed within the framework of number theory, or ‘there is a property \(F\) such that both \(x\) and \(y\) are \(F\)’ (‘\(\exists F(Fx \:\&amp;\: Fy)\)’) expressed within the framework of property theory, can be determined analytically. For these statements either form part of the rules of the language (e.g., expressed as axioms that govern the terms of the language) or are derivable from the rules of the language. When these statements are part of the rules that make up the linguistic framework, they are considered analytic, as are the existential statements that follow from those rules.[14] 