| In the world, we can divide the law into civil law system and common law system, civil law is based on statute law and statutory law as main source of law; common law is based on case law as its main source of law , in which the common law and equity are the two pillars. Theory of consideration on the 19th century Anglo-American classical contract law occupies an important position and promised each other on price incentives is a basic implementation of the standard contract. The theory of consideration plays an important role during the era of capitalism. However, the time will not stop at a certain age. Until the 20th century, more social obligations had an impact on the contract. In civil law countries, good faith is as basic norms of civil law, and as in common law countries, it performed as a break in the traditional contract law enforcement of contracts above the standard. In this thesis, I use the historical method, comparative method to have a systematically analysis with regard to promissory estoppels.This total is divided into five parts, as follows:In the first chapter, I mainly introduce the origin of promissory estoppels in United Kingdom, which is related to the emergence and development of the principles of promissory estoppels. The principle of promissory and estoppel comes from two important principle, namely, estoppels and waiver. The case for Cornell had a very important effect on the development of promissory estoppels. Huges.v . Metropolitan Railway (1877) case was a very good example to show waiver. 1947, Lord Denning in the case of High Tree, with its unique charm set the rules of promissory estoppel.In the second chapter, I mainly introduce the origin of promissory estoppels in United Kingdom, which is related to the emergence and development of the principles of promissory estoppels. Holmes's theory can be said that it played a pivotal role also had a profound impact to the contract law in United States and Corbin used trust as a weapon to the traditional theory of the theory of consideration. 1898 Ricketts.v.Scothorn case was the first time to establish the rule of estoppel in the United States. In the second, "Restatement of Contract Law," it had further instructions for promissory estoppel.In the third chapter, I discuss the four elements of promissory estoppels and the application of promissory estoppels. There exists a promise; The promise has relied on the promise;The promise has been injurior to the promise. Secondly, the case of Combe.v.Combe illustrated that promissory estoppel cannot be used as the cause of action and promissory estoppel applies only to debt reduction in cases of contract changes.In the fourth chapter, I mainly analyze the effect of promissory estoppels and the relief way when breach it. The first part is related to the major impact of promissory estoppels toward the theory of consideration. Maintenance and relief are preferable two ways for the damage.In the fifth chapter, I compare promissory estoppel in common law system and theory of expressing in civil law system. Both of them treat reasonable trust as their main goal. So the good faith is the foundation for both of them. But in different areas, there emerged different principles due to historical background. |