&gt; You should read Russell on definite descriptions<p>An expression is only meaningful in a context in which its free variables are bound. So, in a context in which the concept of “prime number” doesn&#x27;t exist, any statement about “prime numbers” is meaningless.<p>&gt; As for your distinction between philosophical truth, and mathematical truth, you should elaborate<p>Philosophical truth is the correspondence between a statement and reality. Mathematical truth, at least to a formalist like me, is the syntactic property of being substitutable with the symbol “true” in a given context.