The katha upanishad says,

श्वोभावा मर्त्यस्य यदन्तकैतत् सर्वेंन्द्रियाणां जरयन्ति तेज: । अपि सर्वं जीवितमल्पमेव तवैव वाहास्तव नृत्यगीते ।।२६।।

(Svobhava martyasya yadantakaitat sarvendriyanam jarayanti tejah; Api sarvam jīvitamalpameva tavaiva vahastava nrtyagite.) 1. 1. 26

‘These (all the pleasures you have enumerated) are transient, O Death; they (also) wear out the vigour of all the sense-organs of mortal man. Moreover, all life (long or short) is only alpam, little (from the point of view of eternity). Let thy chariots, dance, and song remain with thee only.’

In this brief utterance Naciketa has evaluated all self-sufficient hedonistic philosophies. He and others like him have impressed upon the Indian mind that the object of human life is knowledge and not pleasure. Pleasure and pain are incidental to physical existence; the animals function only on that plane but man has the capacity and privilege to transcend it and achieve intellectual knowledge, moral longing for the eternal and reaches out to it in diverse ways.

Naciketa rejects sense pleasures, firstly because they are tran­sient, and secondly because indulgence in them beyond a certain measure destroys the vigour of the sense-organs and arrests the onward march of the soul to self-knowledge and self-fulfilment. The modern concepts and programmes of social security and of the welfare state suffer from this serious limitation. They involve a concept of man and his destiny which contains features which are necessary but not sufficient.

Man seeking only pleasure, com­fort, and security is man viewed from the surface. Man seeking truth, and courting even pain, discomfort, insecurity, and loss in its wake, is another view of him, a more glorious one, one that betokens his evolutionary march to perfection. Pleasure that does not lead to self-knowledge cloys the senses and produces ennui and frustration in the end. Entertainment, excitement, and exhaustion form a triple sequence in all such pursuits of pleasure. Instead of life expansion and fulfilment, it leads to life contraction and negation.

Reference: The Message of the Upanishads by Swami Ranganathananda (p.288,289)