True knowledge means understanding the eternal soul; nescience means mistaking the temporary body as oneself.Listen — Srila Prabhupada Uvaca
Śrī Īśopaniṣad, Mantra 9–10 — May 14, 1970, Los Angeles 700514IP-LOS ANGELES [27:03 Minutes] Iso-09–10_700514IP-LOS ANGELES Prabhupāda: [chuckles] Hare Kṛṣṇa. Chant. Oṁ pūrṇam adaḥ. Loudly. oṁ pūrṇam adaḥ pūrṇam idaṁ pūrṇāt pūrṇam udacyate pūrṇasya pūrṇam ādāya pūrṇam evāvaśiṣyate [Īśo Invocation] īśāvāsyam idam sarvaṁ yat kiñca jagatyāṁ jagat tena tyaktena bhuñjīthā mā gṛdhaḥ kasya svid dhanam [Īśo mantra 1] kurvann eveha karmāṇi jijīviṣec chataṁ samāḥ evaṁ tvayi nānyatheto 'sti na karma lipyate nare [Īśo mantra 2] asuryā nāma te lokā andhena tamasāvṛtāḥ tāṁs te pretyābhigacchanti ye ke cātma-hano janāḥ [Īśo mantra 3] anejad ekaṁ manaso javīyo nainad devā āpnuvan pūrvam arṣat tad dhāvato 'nyān atyeti tiṣṭhat tasminn apo mātariśvā dadhāti [Īśo mantra 4] tad ejati tan naijati tad dūre tad v antike tad antar asya sarvasya tad u sarvasyāsya bāhyataḥ [Īśo mantra 5] yas tu sarvāṇi bhūtāny ātmany evānupaśyati sarva-bhūteṣu cātmānaṁ tato na vijugupsate [Īśo mantra 6] yasmin sarvāṇi bhūtāny ātmaivābhūd vijānataḥ tatra ko mohaḥ kaḥ śoka ekatvam anupaśyataḥ [Īśo mantra 7] sa paryagāc chukram akāyam avraṇam asnāviram śuddham apāpa-viddham kavir manīṣī paribhūḥ svayambhūr yāthātathyato 'rthān vyadadhāc chāśvatībhyaḥ samābhyaḥ [Īśo mantra 8] andhaṁ tamaḥ praviśanti ye 'vidyām upāsate tato bhūya iva te tamo ya u vidyāyām ratāḥ [Īśo mantra 9] Next verse, verse number..., mantra 10. anyad evāhur vidyayānyad āhur avidyayā iti śuśruma dhīrāṇāṁ ye nas tad vicacakṣire [Īśo mantra 10] Just try. Again. Again. [05:47] "The wise have explained to us that one result is derived from the culture of knowledge, and it is said that a different result is obtained from the culture of nescience." So yesterday we have explained to some extent what is the culture of nescience and what is the culture of knowledge. Culture of knowledge means spiritual knowledge.
That is real knowledge. And advancement of knowledge for comforts or to protect this material body, that is the culture of nescience. Because however you may try to protect this body, its natural course will take place. What is that?
Janma-mṛtyu-jarā-vyādhi [Bg. 13.9]. You cannot relieve this body from repeated birth and death and, while manifested, disease and old age. So people are very much busy for culturing knowledge of this body, although they are seeing every moment that this body is decaying. The death of the body was registered when it was born. That's a fact.
So you cannot stop the natural course of this body. You must meet the process of the body, namely, birth, death, old age and disease. So Bhāgavata says, therefore, yasyātma-buddhiḥ kuṇape tri-dhātuke [SB 10.84.13]. This body is made of three primary elements: mucus, bile and air. That is the Vedic version and Āyurvedic treatment.
This body is a bag of mucus, bile and air. In old age the air circulation becomes disturbed; therefore old man becomes rheumatic, so many bodily ailments. So Bhāgavata says, "One who has accepted this combination of bile, mucus and air as self, he is an ass." Yes. Actually, this is the fact. If we accept this combination of bile, mucus and air as myself...
So intelligent person, a very great philosopher, very great scientist, does it mean that he's a combination of bile, mucus and air? No. This is the mistake. He's different from this bile or mucus or air.
He's soul. And according to his karma, he's exhibiting, manifesting his talents. So they do not understand this karma, the law of karma. Why we find so many different personalities? If it is a combination of bile, mucus and air, why they are not similar?