正共犯區分理論的二元論體系是從形式客觀理論的印象式區分展開的。這種印象模式使人在從事犯罪判斷時，脫離了犯罪判斷的原始基準，即，以分析模式展開的犯罪成立要件。隨著案例檢驗的累積，印象模式很快就受到考驗。基於某種不安的感覺，學說被迫要設法為被分離出去的共犯(Teilmahme)重新鋪設一條通往正犯之路。在教唆犯，重返正犯之路是經由間接正犯以及共謀共同正犯概念；在幫助犯，則是經由共同正犯。然而，間接正犯、共謀共同正犯乃至於共同正犯概念都是與二元論體系牴觸的，因為二元論的原始想像是，只有親自實施構成要件之人才是正犯，而間接正犯和共同正犯恰恰好都否定了這個想像。 間接正犯、共謀共同正犯以及共同正犯概念已在理論的層次將共犯概念的獨立空間壓縮到零。通說維繫共犯概念的憑藉其實是論述中的自我矛盾。不過，要揭示這種矛盾，必須透過案例之間的比對始得顯現，而這種比對工作很難在教科書裡面看到。許多時候我們必須仰賴在教學現場和學生的對話來替代理論之間的對話。然而在教學現場，學生對於書本上的通說有不疑和懷疑兩種反應，其中不疑者會自動複製，懷疑者則最後也經常因為信賴「權威」而強迫自己去複製，同時將心中的疑惑埋葬。這個現象多少也解釋了刑法學裡包括正共犯二元理論在內的若干通說之所以成為通說的原因。

The prevailing dualistic principal-accessory system of criminal parties in germen law was originally a product of the objective formal theory. It provided a formalistic classification scheme which used some ”typical images” to distinguish accessories from the principals. Such an ”image-based” classification model leaves aside the analytical scheme in establishing crimes when there are more than one participant. But the variety of crime scenarios has exposed the limits and unsustainability of the ”image-based” model, and efforts have been made to relocate at least part of the accessories to the principal category. However, once the ”image-based” model breaks, it collapses theoretically forever. Today, the prevailing theory does not announce its own failure and still keeps its dominating influence. It does that by concealing the weakness within its discourse. And it does so well that only a detailed review and comparison of multiple cases can help explore the truth.