Katha-2-1-1-parāñci khāni

Sri Shankara’s Commentary (Bhashya) translated by S. Sitarama Sastri

It was stated that this âtman concealed in all living beings does not shine but is seen by the subtle intellect. What is the obstacle to the subtle intellect seeing the âtman, in the absence of which the âtman can be seen? This valli is begun for the purpose of showing why it is not seen; for it is only when the cause of the obstacle to the attainment of good is known, that it is possible to attempt to remove it and not otherwise. Parânchi ] which go out; khâni ] the senses; the ear and the rest are indicated illustratively by this word khâni. These senses go outward to enlighten their objects, such as sound, etc., as they are of this nature; Paramêsvara has damned them. Who is that? The self-existent, the lord of all, because he alone is always independent and never dependent on others. Therefore, the perceiver sees the external objects which are not the âtman, such as sound, etc., and not the âtman within. Though this is the nature of the world, some discerning man, like turning back the current of a river, sees the âtman within (pratyagâtman) the âtman which is pratyak; it is to denote the pratyak (the inner spirit) that the word âtman is technically used in the world and not to denote any other; and even according to its etymology, it is that alone which the word âtman denotes; for, according to the smriti which declares the derivative meaning of the word âtman, what pervades, what absorbs, what enjoys objects here and what makes the continuous existence of this universe is, therefore, called the âtman. The word ‘aikshat’ meaning ‘saw’, here means ‘sees’; for the tense is not strictly observed in the Vêdâs. How he sees is explained. With his eyes turned with all his senses, the eye, the ear and the rest diverted from all objects. Thus prepared, he sees pratyagâtman; for it is not possible for the same man to be intent on external objects and go to see the pratyagâtman. Why again the intelligent man with such great efforts and by restraining his senses from their natural activity sees the pratyagâtman, is explained. Being desirous to secure immortality, i.e., eternal existence for his âtman.

Links
Various resources on the Kathopanishad
Upanishad Series – Katopanishad Commentary by Swami Chinmayananda