An Etymological Dictionary of the German Language/können
können, pret. pres., ‘to be able,’ from MidHG. kunnen, OHG. chunnan, pret. pres. (sing. kan, plur. kunnum, pret. konsta), prop. ‘to be capable intellectually, know, be acquainted with, understand,’ then also ‘to be able, be in a position (to).’ AS. cunnan (sing. can), pret. pres., ‘to be acquainted with, know, be able,’ E. can; Goth. kunnan (sing. kann, plur. kunnum), pret. pres., ‘to be acquainted with, know.’ In the earlier periods the verbal stem können had exclusively an intellectual sense in contrast to that of mögen, vermögen. Besides the stem kann- preserved in the vb. kunnan (comp. also Goth. kunnan, ‘to recognise,’ AS. cunnian, ‘to explore, attempt,’ see also Kunst, kund, and kennen), there exists in the OTeut. languages a verbal stem which may be represented in Goth. as *knê, *knô; AS. cnâwan, ‘to recognise, know,’ E. to know; OHG. irchnâan, bichnâan, ‘to recognise’; OHG. úrchnât, f., ‘perception’ (Goth. *knêþs, f., is wanting); the OHG. nominal vb. irchnuodilen, ‘to become perceptible,’ points to a Goth. *knôþla-, ‘knowledge.’ The three Teut. stems kann, knê, knô occur in the non-Teut. languages, Gr. and Lat. gnô in γιγνώσκω (ἔ-γνω-ν), ‘to recognize,’ γνῶσις, ‘knowledge,’ Lat. gno-sco, nô-tus, nô-tio; OSlov. znają, znati, ‘to recognise’; OIr. gnáth, ‘acquainted.’ Ind. forms a pres. from a root *jan, the pret. from a root jnâ, jânãmi, jajnáu (comp. part. jnâtá), ‘to know’; the Teut. root kann from gen-n appears in Lith. żinaú, ‘to know, recognise, perceive,’ pa-żintis, ‘knowledge,’ Zend â-zaiñti, f., ‘information,’ OIr. ad-géin, perf., ‘cognovit.’ This wide ramification of the closely allied Aryan root gen, gnô, ‘to recognise, know,’ is generally recognised, but its connection with the root gen, ‘to beget, bring forth,’ and the variants gnâ-, gnô-, discussed under Kind, König, and kennen, is problematical. Both seem to be united in AS. cennan, ‘to bring forth,’ and ‘to generate,’ Gr. γνωτός, ‘related by blood,’ and ‘discernible, known.’ The distinction, however, between the physical and intellectual senses of the word must have been made previous to the division of languages, since it exists in all the Aryan groups. Comp. kühn.