Sokhyo Jo
Max Planck Institute for the History of Scienc
Max Planck Institute for the History of Science, Boltzmannstraße 22, 14195 Berlin, Germany
This lecture explores how calendrical calculation (rtsis) functioned in Tibetan intellectual history as a mediator between empirical observation and transcendent cosmic reality. Grounded in the Kālacakra Tantra, the calendar operated not only as a chronological tool, but also as a sophisticated means of synchronizing the phenomenal world with the principle of the universe. By combining Tibetan medical calendrics with the cosmological framework of the fourteenth-century scholar Dolpopa Sherab Gyaltsen, I hope to reveal how calculations of calendrical time resolved tensions between astronomical anomalies and authoritative cosmic models, and ultimately transformed the calendrical calculation of the Buddha’s teaching (bstan rtsis) into a cosmological device that reveals the manifestation of timeless, transcendent reality within the phenomenal universe. In Tibetan medicine, calendrical correction was driven by a need for cosmological synchronization. Confronting observational discrepancies between the descriptions of the inherited medical texts and the actual night sky, physicians like Changdag Namgyel Draksang utilized empirical astronomical data, such as the exact positioning of dawn stars and lunar mansions, to correct corrupted seasonal regimens. Building on this empirical base, scholars integrated these astronomical cycles directly into clinical practice. They maintained that balancing bodily humors (such as Bile, Phlegm, and Wind) through sophisticated yogic breathing should be aligned with shifting celestial time. Medical calendrics thus translated macro-cosmic celestial movement directly into micro-cosmic therapeutic interventions and re-established a correspondence between the universe and the human body. Parallel to this medical science, Dolpopa also utilized this framework of calendrical calculation of the Buddha’s teaching to establish a temporal architecture for ultimate reality. He employed bstan rtsis to calendarize the cyclical time of the four yugas, mapping historical events such as the birth of the Buddha onto a cosmic schema and allowing the timeless reality of the Buddha-nature (tathāgatagarbha) to manifest through measurable, astronomical time. Ultimately, in both the physiological sciences and Dolpopa’s cosmological framework, the calendar functions like a Möbius strip: a continuous loop where astronomical measurement and transcendent reality, the internal body and the external cosmos, seamlessly transition into one another.
Biography
After earning his Ph.D. from Harvard University in 2016 with a dissertation on skar rtsis—a Tibetan astronomical system based on the Kālacakra Tantra—Sokhyo Jo has been exploring the philosophical and religious meanings of time found across various Tibetan Buddhist texts. Building on these studies, he is currently developing his own theory of time, framed not only within the context of Tibetan Buddhism but also as a universal topic in the humanities.
Organizer(s)
Address
Max Planck Institute for the History of Science, Boltzmannstraße 22, 14195 Berlin, Germany
Room
Zoom/Online Meeting Platform
Contact and Registration
We welcome both internal and external guests. Registration is only required for in-person attendance. All talks will be streamed via Zoom. For further information about the colloquium series, please contact Luigi Rogora (lrogora@mpiwg-berlin.mpg.de). Feel free to distribute information and Zoom link widely.
Zoom link: https://eu02web.zoom-x.de/j/69059029684?pwd=DVJHzwJwCl2Uy2QhzhPcoJRGzUASuX.1
Meeting ID: 690 5902 9684
Passcode: 301249
About This Series
The Tibetan term tsi (“calculation”) represents the broadest term for astral sciences, interconnecting diverse disciplines deeply embedded within the classical Buddhist fields of knowledge. Far from being intellectually isolated, High and Central Asia engaged in dynamic cultural exchanges spanning from India, Tibet and the Himalayas, Mongolia and Central Asia, up to China. Within this framework, distinct streams were synthesized: computational astronomy, tied to the Kālacakratantra, used to model celestial mechanics and construct calendars; astrological systems linked to the Indian Svarodayatantra (Yuddhajayārṇava); and mantic practices like geomancy, which claimed Chinese origins while deeply rooted to local contexts.
Furthermore, by viewing the human body as a microcosm structurally attuned to cosmic movements and earthly shifts, astral sciences enabled an interconnected understanding of change across time, space, and somatic experience, eventually connecting it to medical expertise. These practices flourished mainly within monastic centers but spread through trans-regional encounters, mediated primarily by Tibetan and Mongolian scholars.
The colloquium series “Sky, Earth, and Bodies: Astral Sciences across High and Central Asia” highlights recent contributions to the field and opens critical perspectives on the practical life of science in these regions. Invited speakers will trace the adaptation and transmission of astral knowledge across High and Central Asia. Specifically, the series addresses geography and cartography, astral medicine, astronomy, astrology, and mantic arts as they traveled between sources, languages, places, and people, offering a broader understanding of the history of knowledge across trans-regional Asia.
