The legal methodology is constructed upon two fundamental issues : finding the law and applying the law. The concurrence of crimes in criminal law pertains to the second issue. This term stands not only for the question “how the accumulating criminal norms can be applied for the solution of the legal problem at hand” but also stands for the answer to this question. It will be demonstrated within this article that the principles “nulla poena extra culpam” and “nulla poena sine lege certa” resolve the issue of applicability of concurrent criminal norms. In addition, the introductory provisions of the Turkish Civil Code, which shed light on the topic, will also be examined within this discussion concerning legal methodology. On a separate note, this methodological discussion has been limited not to exceed the scope of an article. Therefore, the discussion on the concurrence of crimes as a methodological issue in criminal law has been narrowed down to the issues of attempted lex specialis and completed lex generalis. These issues will be addressed under “pseudo-concurrence” and “ideal concurrence” titles. Consequently, these evaluations will introduce two new discussions : whether “lex consumens derogat legi consumptae” actually causes the relationship of exclusion between the norms and whether Art. 43 / I s. 3 Turkish Penal Code constitutes an obstacle to the application of Art. 44 Turkish Penal Code. These discussions will be examined in light of methodological principles.