From Prof. Mathes's paper, we know that:
    1. The ultimate reality is empty of other, namely, empty of accidental stains. But it is not empty of self, namely, not empty of an own being. 2. The ultimate reality is permanent. It is beyond the three times.
    3. The Buddha-nature is beyond words and thoughts.


    從馬特斯教授的論文中,我們知道:
    1. 究竟實相是”他空”,也就是空於客塵染污;但究竟實相不空於自性,也就是並非“自空”
    2. 究竟實相是永存的,超越於三世的。
    3. 佛性是超脫於語言及思維的。

    Klaus-Dieter Mathes

    University of Vienna
    Prof. Dr. Klaus-Dieter Mathes is the Head of the Department of South Asian, Tibetan and Buddhist Studies at the University of Vienna. His current research deals with Tibetan Madhyamaka, Yogācāra and the interpretations of Buddha nature from the 14th to the 16th century. He obtained a Ph.D. from Marburg University with a study of the Yogācāra text Dharmadharmatāvibhāga (published in 1996 in the series Indica et Tibetica). His habilitation thesis was published by Wisdom Publications under the title A Direct Path to the Buddha Within: Gö Lotsawa´s Mahāmudrā Interpretation of the Ratnagotravibhāga (Boston: 2008). Recent publications include The Other Emptiness: Rethinking the Zhentong Buddhist Discourse in Tibet (SUNY, 2019) and A Fine Blend of Mahāmudrā and Madhyamaka. Maitrīpa’s Collection of Texts on Non-conceptual Realization (Amanasikāra) (Vienna, 2015). He is also a regular contributor to the Journal of the International Association of Buddhist Studies.
    https://ufind.univie.ac.at/en/person.html?id=88065

    Sources:
    Mathes, K-D 2019, Tāranātha’s Twenty-One Differences with Regard to the Profound Meaning: Comparing the Views of the Two Zhentong Masters Dolpopa and Shakya Chokden. in K-D Mathes & MR Sheehy (eds)

    The Other Emptiness: Rethinking the Zhentong Buddhist Discourse in Tibet., 8, State University of New York Press (SUNY Press), Albany, NY.

    A Direct Path to the Buddha Within
    Go Lotsawa's Mahamudra Interpretation of the Ratnagotravibhaga Part of Studies in Indian and Tibetan Buddhism
    By Klaus-Dieter Mathes
    About the author: Klaus-Dieter Mathes earned his doctorate at Marburg University, and is a Professor of Tibetology and Buddhist Studies at the University of Vienna, Austria. He previously worked as a research fellow and lecturer at the Asia Africa Institute at the University of Hamburg, Germany. His research in progress deals with the Indian origins of Tibetan Mahamudra traditions. He is also a regular contributor to the Journal of the International Association of Tibetan Studies.

    https://www.simonandschuster.com/authors/Klaus-Dieter-Mathes/451424980