In this paper I presuppose that liberty has a structure. Such structure of liberty also exits in private law. I would especially deal with some issues of contract law. Contract law is the core in libertarian legal theory. That is a reason why I focus on contract law.
Libertarians respect the principle of freedom of contract. This is one of main principles of so called “classical private theory” or classical contract theory. By contrast, modern contract law is based on Welfarism which is criticized by libertarian in general. If modern contract theory is in harmony with Welfarism, it seems that libertarianism contributes not to these field of modern contract law theory. But I believe that it is a misunderstanding about libertarianism. We should explore practical implication of libertarianism for modern contract law. I argue that libertarianism provide useful suggestions for resolving a number of problems that modern contract law theory have to cope with.
Firstly I indicate a number of dilemmas in modern contract law as follows. Although in modern contract law “consent by parties” would be often regulated for weaker parties, such regulations are not necessary produce the desired result. This is the point of libertarian argument. For instance, I refer to an example with regard to a relation between landlord and tenant in Land and House Lease Law in Japan.
Secondly I explain libertarian arguments about “the nature of market order” and “the knowledge of the circumstance in market”. Indeed there are substantial differences in knowledge between consumer and company. But such differences are not necessary good reason to intervene to market. According to libertarian argument, market order is one of spontaneous order. So the knowledge never exists in concentrated, integrated form. If we wish to make good use of such knowledge in market, we have to take seriously the libertarian theory.
