稅法與私法的規範衝突,基於稅法與私法均屬整體國家法秩序的一部份,須臣服於憲法之下,憲法同時扮演者調和兩者價值衝突的角色,透過利益衡平,調和稅法與私法的規範衝突,然而所謂的「衡平」又往往是取決於個案的類型特徵與所涉基本權的規範關聯。因此,本文於方法論上乃採取「體系正義」(Systemgerichtigkeit)的思維。稅法承接私法機制,如婚姻、家庭、繼承、契約交易等制度,課稅事實乃依附其上,然課稅必然產生侵入財產權的經濟效果,是否因此對於私法秩序造成不當干預,可資衡量的基準有二,一為私法自治,另一則為基本權制度性保障。具體的衡量又可再進一步區分基本權保障強度決定之。
The topic of acceptance and adjustment of private laws by tax laws shall be deemed as norm conflict between tax laws and private laws, and it should be resovled under the harmonization of constitution. The method that constitution harmonizes the aforesaid norms conflict is to weigh the goals of tax laws against the fundamental right and order that private laws protect. During the weighing, the methodology of "Systemgerichtigkeit" can be adopted.