Systemic validity has been criticised based on its supposed inability to account for the validity of so-called extra systemic norms and unconstitutional statutes. The article argues that these criticisms are not sound by demonstrating that no truly extra-systemic norm is actually recognised as valid within the legal system and by claiming that there is nothing non-systemic with unconstitutional statutes. On the other hand, with respect to norms of public international law, foreign law applied in cases of conflict of laws and the norms of the former legal system, what is concerned is not the incorporation of the norms themselves, but the contents thereof. This means that there is a norm within the legal system identical in content with an actual extra-systemic norm. This content-based incorporation is usually carried out with two different methods respectively called 'dynamic' and 'static' incorporation and neither case provides a challenge for the understanding of systemic validity.