This thesis attempts to trace the continuous philosophical developments, if any, from the Abhidharma to Pramana thoughts. It has been divided into four parts. Part I is an introduction of this project, it overviews the outline and problems of each chapters. Reader may find the introduction chapter useful for grasping the overall objective and the significance of this research. Part II deals with the problem of perception, the issue of non-existent object, time paradox embedded in the contextual arising of citta-caitta, and the theory of language of Abhidharma Buddhism as discussed in Ny. Some clear textual evidence show that both the Vaibhasika and the Sautrantika admit a kind of realism in their theory of perception, though the claim of realism of the Sautrantika is not so strong as that of Vaibhasika. However, the Vaibhasika linguistic realism was refuted by the Sautrantika.This may due to the gradual development of linguistic transcendentalism according to which the citta partakes in the process of conceptualization and representation. Part III traces the legacies of Abhidharma epistemology, it includes the causal model of mind, the transformation of the basis, the theory of language and the inferential function of drstanta in Buddhist logic, all of which, to a certain extent, were inherited from the Abhidharmika and further developed by the early Yogacara and Pramana thoughts. Other than the assessment of the problem of epistemology and its related issues in different cognitive models in regard to alayavijbana, the Buddhist ontology of language meaning and the nature of sign, I have also evaluated the age-old problem of Yogacara idealism by arguing that the perceived object of Yogacara is not necessarily led to idealism, if we comsider the perceived object as an intentional object which is real in regard to the intending act. By doing this, we may overcome, at least in part, the ontological problem of illusive object with respect to mind. Part IV is a critical conclusion and supplement of further comments on the issues of the “eye sees” theory, Yogacara and Pramana cognitivism, problem of other minds, theory of sign and its relation to the nature of Buddhist logic, and a further discussion on the problem of idealism. The closing section is ended up with some tentative observations of what we have discussed. I suggest that though we may not able to cleanse all of the idealistic suspects in both Yogacara and Pramana thought, those tentative observations may serve as the possible pivotal topics for future research if we want to understanding more profoundly the reason why the early Yogacara as well as the Pramanists had still retained some of the rigors of epistemological realism of Sarvastivada-Vaibhasika.
