# Letter to the reader using conventional notation

**An anthology of somewhat strange answers:**

*1. "The expression 'true' in ZFC depends on what one understands by a model. This, however, is not unambiguous for ZFC."*

*2. "The separation axioms just state that one can do the 'intersection' of a*

**set**with a**formula**, however, it does not claim that it actually says what this intersection set**is**"*3. "ZFC is incomplete. We assume ZFC to be consistent. Due to incompleteness the separation axioms may lead to so-called Schrödinger-sets, i.e. sets whose status is unknown, just as one does not know if Schrödinger's cat is dead or alive. Progressing to a fixed ZFC model (i.e. a consistent completion) the Schrödinger phenomenon of definition disappears. But nobody knows which ZFC model one should favour. Already the first additional axiom is controversial, leave alone completion."*

*4. "Axiomatic set theory usually is understood as a foundation theory, that carries a different status as compared to 'axioms' of a certain kind of mathematical structure, i.e. as stipulations in the definiens of the definition of a certain kind of mathematical structure (e.g. a certain geometry)."*

*5. "Set theory also has pragmatic and normative features that transcend pure logic. The analysis of set theory rather belongs to the methodology of sciences."*