In the global age, it is possible to say that we live in the condition of disunion and disagreement in respect of human and society. In the realm of human, we feel so many inner disunion due to deep discrepancy of human being. And in the realm of society, they experience so many outer disagreement owing to heterogeneous elements of social condition.
Wonhyo's theory of harmonization responded the above question fundamentally in Korean peninsula about 1,300 years ago. His theory, I think, will give light on the path where today's ordinary people want to solve the question. Because his theory accepts the whole and a section equally, and reconciles diversity and heterogeneity evenly. And because his theory changes disunion and disagreement into union and agreement.
In Korea, from 1960's there are a lot of outcome of research on Wonhyo's theory, but there are some problems in the outcome. In the case of researching his representative books only, there is a problem saying a section as the whole. And in the case of researching his whole book, there is also a problem not having abundant grounds for making an assertion.
Considering these problems, this thesis collected the cases of harmonization in Wonhyo's remained whole books. And with the help of the cases, this thesis researches the Wonhyo's theory of harmonization specifically under 4 small topics, those are 'the background of harmonization'(Chapter 2), 'the structure of harmonization'(Chapter 3), 'the manner of harmonization'(Chapter 4), and 'the grounds of harmonization'(Chapter 5).
The main primary source of this research is the cases of harmonization in Korean Buddhism Collection vol. 1. And in this research, the term of 'the cases of harmonization' will be used under two conditions. Firstly, plural theories should dispute against each other. Secondly, the decision should be made not by the person concerned but by an outsider.

In the second chapter, there is an effort to answer the question, "What is the background of harmonization?" I hope that the answer will be found one by one in Wonhyo's remained works including the cases of harmonization.
In the field of thought of perfection of wisdom(prajñā) and madhyamika(mādhyamika), he says that one leaves relative concept like existence and nonexistence, transcends literal expression, and departs not only from each side way but also from middle way when he attains enlightenment. And in the sphere of thought of consciousness-only (vijñapti-mātratā), he says that objective aspect, subjective aspect, self-witnessing aspect are all same, and that four phrases about paratantra-svabhva(依他起性) are all included when one takes equal opinion.
In the sphere of thought of one vehicle (eka-yāna), he says that the teaching of one vehicle is the whole thing which all Buddhas teach sentient beings from enlightenment to nirvana, and that Lotus Sūtra contains ultimate teachings. And in the realm of thought of buddha-nature (buddha-dhātu), he says that the body of buddha-nature transcends all extreme views, and that Nirvāna Sūtra have sameness and non-duality.
In the realm of thought of one mind (eka-citta), he says that one mind is grounds of all dharmas and substance of Buddha nature. And that one mind embraces existence & nonexistence and the true & the common, and transcends cause & effect and nature & character. And in the field of thought of Huayan, he says that the state of grand-dharma(普法) is that every dharma holds perfect inter-fusion with each other, having no obstacle in the space and time.

In the third chapter, this thesis wants to answer the question, "What is the structure of harmonization?" The cases of the harmonization have various topics, which are chiefly theories in Buddhism. And, the cases have the three parts which are 'the assertive part', 'the debating part', and 'the decisive part'. After having looked into the overall structure of the cases of the harmonization with the information about the three components, we could devide the cases into 4 types. Among these, mostly common form of the cases is the type 2 which has the assertive part and the decisive part, not having the debating part.
Firstly, 'the assertive part' unfolds the points of all theories on the given topic. Researching the components of the assertive part, we can find the three small parts, those are 'the principal clause', 'the causal clause', and 'the evidential clause'. And, after researching the structure of the assertive part with the information about the three components, we can devide the part into 7 types. Among these, mostly common form of the part is the type 5 which has only the evidential clause, not having principal clause and causal clause. While there are mainly two theories per one case of the harmonization, in 12 cases of the harmonization there are over three theories per one case.
Secondly, 'the debating part' unrolls the attacks and the defenses to the parter. Looking into the components of the debating part, we can find the two small parts. One is 'the clause of attack', which reinforces the assert of himself or discloses the weakness of the parter, and the other one is 'the clause of defense', which protects the attack of the parter or absorbs the argument of the partner. And, looking into the structure of the debating part with the information about the two components, we can devide the part into 5 types. Among these, mostly common form of the part is the type 3 which has only the clause of attack, not having the clause of defense.
Thirdly, 'the decisive part' evaluates and judges the raised all theories. Looking into the components of the decisive part, we can find the three small parts, those are 'the principal clause', 'the causal clause', and 'the evidential clause', which are very similar to the components of the assertive part. And, looking into the structure of the decisive part with the information about the components, we can devide the part into 6 types. Among these, mostly common form of the part is the type 2 which has principal clause and causal clause, not having the evidential clause.
In the fourth chapter, this thesis wants to find an answer to the question, "What is the manner of harmonization?" The source of the answer is in the decisive part in the cases of harmonization. At the principal clause in the decisive part, we can see the following 5 types of judgment to the raised theories. And, at the causal clause in the decisive part, we can see the modes which are used in 5 types of judging manner.
In type 1, all theories are right. The type 1, is the most common in 5 types and uses two modes in the cases of harmonization. Mode 1 reconciles all theories 'under single criterion', saying that the objects of argument are included to the same category. Mode 2 reconciles all theories 'under double criteria', saying that the objects of argument are apparently different just because the grounds of speakers in the sūtras are different.
In type 2, all theories are right and wrong at the same time. The type 2 is particular in the theory of Wonhyo and uses four modes in the cases of harmonization. Mode 1 reconciles all theories in 'the method of the transcendency of language', saying that the speech of Buddha must be taken not by 'word' but by 'meaning'. Mode 2 reconciles all theories in 'the freedom of affirmation and negation', saying that all theories are affirmed in the first half and all theories are negated in the second half. Mode 3 reconciles all theories in 'the freedom of existence and nonexistence', saying that theories relating to existence are affirmed in the first half and theories relating to nonexistence are affirmed in the second half. Mode 4 reconciles all theories in 'the freedom of sameness and difference', saying that all theories are ‘different' firstly, are ’same' secondly, and are ‘neither different nor same' thirdly.
In type 3, one theory is right at one point of view and is wrong at another point of view. In type 4, one theory is right and another theory is wrong. And in type 5, the topic of the argument is 'actually' different from the viewpoint of the judge. These type 3, 4, and 5 can be understood easily in a commonsense point of view, so further research will not be needed.

In the fifth chapter, I hope to find an answer to the question, "What is the grounds of harmonization?" The source of the answer is in the decisive part in the cases of harmonization. Scanning the evidential clause in the decisive part, we can find easily 'the reason' and 'the sūtras' as the grounds of harmonization.
'The reason' is the terminology having vague elements due to not have literal form. Analyzing the cases that have the terminology, we can tell the detailed elements to a certain extent. Firstly, the characteristic of the reason is the thing which does not stick to one side, is similar to the Buddha's mind, is similar to the Buddhist speech, and is righteous thing in itself. Secondly, the existence of the reason is the thing which can be found in everywhere, can be found particularly at the speeches in the sūtras, and can be found specifically in the teachings of One-Vehicle. Thirdly, the expression of the reason can be possible in language but can not be possible in language at the same time.
'The sūtras' are consisted of clear elements due to have literal form and many kinds of quoted sūtras are found in many cases of harmonization. In the meanwhile the sūtras are needed the process of 'interpretation' which confirms the meaning of the sūtras in order that the sūtras could be used actually as the grounds of reconciliation.
In The Essence of Nirvāna Sūtra, there is a paragraph, "Firstly, in the case of 'different word and same meanings', it is possible to reconcile the dispute as the objects of argument are same in the context of the sūtras. Secondly, in the case of 'different words and different meanings', it is possible to reconcile the dispute because the grounds of speakers in the sūtras are different."
Referring to the above paragraph, we can divide 'the interpretation of sūtras' into 4 types. The literal interpretation(type 1) is used in the occasion that the interpretation is not needed. The systematic interpretation(type 2) is used in the occasion that the words are different but meaning is same. The conditional interpretation(type 3) is used in the occasion that the words are different and meaning is also different. And the subjective interpretation(type 4) is used in the occasion that the grounds are weak.