客觀淨額所得原則的憲法基礎以及界限（譯文）

Verfassungsrechtliche Grundlagen und Grenzen des objektiven Nettoprinzips

Although the “objective net income principle” is one of the subsidiary principles of the ability-to-pay principle, the author is trying to find the “objective net income principle’s” basis on the Constitution Law, in order to highlight its important position for the law. He also stresses that its limitations are grounded in the legality under examination of the “principle of proportionality”. The author focuses on the fact that the tax system is based on the “consistency principle”. Even if the “objective net income principle” on the income tax law relates only to income-related expense deduction, the author connects the income-related expense on the income tax law, through a developed vision, with the “consumption costs” on the turnover tax law and the “private”-related costs. He stresses that non-disposable income not only cannot be used as the assessment basis of the income tax law, but also cannot be as assessment basis of the turnover tax law, if this is the result of the consumption’s costs. In addition, the fees of relating to the need of surviving or the obligatory provisions should be allowed to deduct, even if they would be caused by the “private”.