||The present thesis is a philosophical research on the doctrine of Sa̅ka̅ra-vijña̅nava̅da, a branch of Yoga̅ca̅ra Buddhism, according to Xuanzang's Treatise on Demonstration of Consciousness-Only (Cheng Wei Shih Lun ) and other related Yoga̅ca̅ra treatises (śa̅stra). Within this thesis, Sa̅ska̅ra-vijña̅nava̅da's understanding of 'ignorance' (avidya̅) is investigated through the theory of 'Conceptualization-Only' (vijñapti-ma̅tra) and 'Semantic Manifestation of Meaning\Object' (artha-pratibha̅sa). Different from traditional hermeneutic model, which mainly presents Vijña̅nava̅da as absolute idealism either in cosmological or metaphysical sense, I try to argue in my research that Vijña̅nava̅da as a Buddhist tenet, its primary concern is existential and axiological issues, while epistemological and semantic problem is its secondary concern. The thesis is composed of eight chapters. The Introductory Chapter deals with subject matter, main theme, structure and the methodology of the whole project. Chapter One is a description of the basic nature of modern Buddhism and the methodology of contemporary academic studies of Buddhism. The models that this chapter deals with are Engaged Buddhism and Buddhist Theology. Chapter Two is an investigation of the possible philosophical implication within Yoga̅ca̅ra theory of meditation. Through the glass of phenomenological reduction, I try to argue that Buddhist Meditation is not 'mystic' as it seems. In fact under its religious rhetoric, theory of meditation does imply certain basic characteristics of transcendental method of philosophy. Chapter Three is an investigation of Yogacara's understanding of intentionality, namely, Transformation of Consciousness (vijña̅na-pariṇa̅ma). The theory is an explanation on consciousness (vijña̅na)'s active function in creating its intended object. In this chapter, the viewpoints of both parties involve in the hot debate of Japanese scholarship on the issue will be reviewed while J. N. Mohanty's explanation is adopted to solve Japanese scholars' weaknesses. Chapter Four is on Two Hindrances (dvi a̅varaṇa), which is composed of Afflictive Obstructions (kleśa̅varaṇa) and Obstructions to Knowledge of Objects (jñeyavaraṇa). This chapter will be focused on the innate (sahaja) grasping of two hindrances. Chapter Five is a discussion on theory of language structure. Section I deals with Buddhist concepts on sound (śabda) in phonemics sense, syntactics (vyañjanaka̅ya), procedures of semantic construction through name (na̅maka̅ya) and sentence (padaka̅ya). Section II is about the mind's mechanism in language operation, the pragmatic aspects of language according to various contexts and the relation between proposition and propositional attitude. Chapter Six is on Semantic Object (artha) and its Manifestation (pratibhasa). Section I is a review on the development of Buddhist concepts of object and the Indian debate on cognition with and without aspect (aka̅ra). Section II is a description and explanation on the basic characteristics of semantic object (artha, a̅lambana) according to Cheng Wei Shih Lun . Section III is an explanation on the essential concept of Yoga̅ca̅ra Buddhism, namely, 'conceptualization-only'(vijñapti-ma̅tra), through the theory of Manifestation of Semantic Object (artha-pratibha̅sa). Chapter Seven is on Two Hindrances that are ideologically or intellectually (parikalpita) aroused. Chapter Eight is the Conclusion Chapter. Section I is a summary of the interpretation presented here. Section II discusses the limitation of the research. Section III is a dialogue between Yoga̅ca̅ra Buddhism and Engaged Buddhism.