The four signs/reasons: Def. by Jamgön Kongtrül: 1) gzhan la grag pa'i rjes dpag, 2) 'gal ba brjod pa'i thal 'gyur, 3) rgyu mtshan mtshungs pa'i mgo snyoms, 4) sgrub byed bsgrub bya dang mtshungs pa'i ma grub pa bzhi, "The four: 1) inference renowned to others; 2) consequence expressing a contradiction; 3) [confutation thru] similarity of the reason/argument; and 4) non-establishment consisting of the similarity of probans and probandum." [mss]