When asked about the opinion on the real taxation principle, Prof. Kitano regards it affirmatively as a shield with which tax collector abuses the economy observation method. Prof. Kitano points out furthermore, that so-called real taxation principle is not a principle of tax laws, but an extended explanation of the application tax laws. What’s more, it also undoubtedly breaks the principle of no taxation without law. Many scholars consider the real taxation principle as the jurisprudent extension of the principle of imposition by capability, with which the basic elements of real taxation principle are built up. They regard the principle of no taxation without law, principle of imposition by capacity, economic imposition principle as the three basic principles of tax law, and they are corresponded to formal justice, material justice and technique justice respectively. But Prof. Kitano insists that the principle of no taxation without law is on the top status of tax law and is the universally accepted principle, and the principle of imposition by capability has only positive meaning in legislative aspect. We can find such conclusions, if we learn Prof. Kitano’s academical standpoint and investigation routs.

　　Prof Kitano‘s point bring about great impaction to learners, which are the result of Professor’s standpoint about constitutionalism and his subversive creation to the traditional tax law. He thinks impartiality theory doesn’t stand up, and the practice of restricting and reducing taxpayer’s right deviates from our modern tax law principle, so it is a false theory. Prof. Kitano makes material imposition contact with Nazi, and its motive lies in pressing small enterprises and ordinary people. Though we are not sure that Japanese tax law academe make an review on material imposition principle, because Prof. shows a great surprise to this principle, there is no objection that material imposition principle applies to imposition practice, and imposition by capability principle apply to the legislative instruction.

　　As an idealistic form, imposition by capability principle bases on a new tax law theory --- tax capability theory, which corresponds to tax benefit theory and how to implement taxation justice, is the principle’s core thinking. Weak points that most of taxation cannot parallelize the government service one by one. Muller introduce economics theory and the brings forward the taxation sacrifice theory --- taxation is an kind of consideration to get public service. This theory promotes the emergence of imposition by capacity principle, along with the thoughts of egalitarian and social right. Prof. Kitano regard imposition by capacity principle as a legislative instruction, and it has the origin and restraint in constitution. It is indeed a view full of courage and innovation.

　　Thinking much of individual and jurally equality are the two characters of modern jurisprudence. Generally, essential human rights include freedom right, social right and existence right. Prof Kitano think that the original idea of freedom right doesn’t allow legislative and administrative discretion, and social right doesn’t mean concrete right, but conduct obligation from opposite law. Imposition by capacity principle is the embodiment of social right, and the lowest limit ensures existence right. Prof also figures such capability includes quality and quantity, and both sides decide actual capability.

　　How to expatiate on the difference between academic theory and legal principle? Usually, legal practice has been consequentially coached by some theory that is popular opinions. Though colliding among all kinds of theory can help us distinguish values, it is different to find such values in the course. For example, legalism emphasizes that application and explanation of tax law should accord with legal essentials of taxation, whereas economics insist on just taxation. Kruse think imposition by capacity can be significant only in Economics, but Prof. Tanaka think it isn’t necessary to regulate in the law, when the principle would be referred, which means this principle is not only affirmed in the legislation, but also acknowledged in the practice. Kira Minoru supports the principle of material imposition, and they insist that this principle be available to legislation and practice, obviously, which is another value judgment.

　　Disparate opinions bring about trouble to learners, because theory commonly oriented the practice. What is the tax base? Generally speaking, it depends on taxpayer’s capacity, so people in trouble should be exempted. However, it is illegal that people evade taxation by false transactions. We can find their justice and legality only in law field, But it also produce absurdity, for example, how to balance subjective judgment and objective requirements? Is the principle of imposition by capacity Plato ideality, and is the principle a kind of legal idea or a kind of principle in tax law?

　　The understanding about economy observation method has come to relatively accordance after vicissitude for one century. We can conclude that such vicissitude is contacted with amalgamation and separation between civil law and tax law. Whether terms or method show that tax experienced from economic field to legal field, So it is the most important to comply with substantive and procedure regulations ,whether in macroscopically constitutional theory or in microcosmic civil opinions ,and economic judgment only help to legal judgment. Mrs. Becker’s opinions not only offer academic support to imposition by capacity, but also respond to Papier’s opinion. As far as Prof. Kinato’s opinion, he thinks there is a sheer limit between the principle of material imposition and imposition by capacity, because he has a different understand about “by capacity”. So there is a far way to clarify the principle’s connotation and sphere of application.