उपमानम् — Knowing the Unseen through the Seen: Models and Analogy

Upamāna, "measuring alongside", is the device of knowing the unseen through the seen. It is the only tantrayukti in this series found in Kauṭilya's list alone: Kauṭilya defines it as "establishing the unseen by the seen", with an instruction from his chapter on the settlement of the countryside — the king "should favour, like a father, those whose exemptions have ended." Suśruta and Caraka have no upamāna among their tantrayuktis, but neither does without the thing itself: Suśruta's nidarśana and Caraka's aupamya, defined in his rules of debate, do the same work. This article quotes Kauṭilya's definition, sets it beside the Nyāya definition of upamāna as a means of knowledge and Caraka's aupamya, and distinguishes three uses of likeness in the śāstras: to learn what a word refers to (Nyāya), to name and explain (Caraka, Suśruta), and to guide conduct (Kauṭilya). Three objections are examined: that upamāna is only inference, that its absence from the medical lists shows it to be dispensable, and that an argument from likeness — "like a father" — can justify anything. It concludes that Kauṭilya's upamāna is a model: a known relation offered as the pattern for an unknown one, valid within the respect in which the likeness is well known; its modern forms are the model organism, the scale model, the guiding metaphor of a theory, and analogy in law. Series: तन्त्रयुक्तिविमर्शः · Tantrayukti Studies, TY-2026/13. Loci: AŚ 15.1.27–28. Online version: https://sanskritmanthan.in/a/ty-13-upamana