Lyle

First off, why did you feel the need to comment on my profile page?

"As I understand the argument from ignorance ('assertion that a proposition is necessarily true because it has not been proven false'), can one make the argument that AnCap is an argument from ignorance because it asserts, a priori, certain propositions (ie. laws of economics) to be necessarily true (ie. axioms) that cannot be proven false (ie. they are non-experimental)?"

Axioms, or premises, are starting points for logical reasoning. As such, they themselves cannot be proven true or false. They can only be accepted or rejected.