The human being, in the Buddhist perspective, is an everchanging stream of consciousness or to be more precise, a perpetually changing movement or a process of psycho-physical energy with no permanent Ego or soul principle in it. This stream of psycho-physical energy which constitute the human organism, this flame of being, is held together and propelled into the ocean of becoming, the journey of life, samsara sagara, by an essential craving for life, Trishna. This Desire, the Craving for life is the root cause of all sorrow, bondage and suffering. It is the engine which propels the fly-wheel of samsara; it is the psychological principle which forges karma and compels the human being to be born again and again in an endless series of sorrowful births. Thus in the Buddhist perspective, sorrow born of craving, is the essential nature of life as it is. Whatever happiness or pleasure we feel is another form of sorrow.
But we must remember here that this Desire of which Buddha spoke is not the various forms of conscious desire of the surface being of man for the outer objects but the very bedrock of desire, a deep-rooted and essential craving for the enjoyment and experience of life, not only the gross physical and sensuous experiences and joys of the body but also the experiences and joys of the mind, not only the experiences and joys of the terrestial life but also the heavenly experiences and joys of the life of gods. In a well-known Buddhist treatise “The Debate of King Milinda”, the Buddhist monk Nagasena describes “feeling” as the cause of craving and explains further the “characteristic mark of feeling” as “being experienced and enjoyed” And Buddha says in one of his discourages “where does this craving arise and takes root? Wherever in the world there are delightful and pleasurable things, there this craving arises and takes root.” This is the reason why Buddhist yoga stresses much more on states of tranquil severity, detachment, insight and compassion rather than on mystic or psychic experiences, visions and ecstasies. For longing towards these inner experiences is as much a form of craving and desire as the longing for physical and sensuous enjoyments.
This essential craving for life is ever unfulfilled. It can never be fulfilled because there is nothing in life which is permanent. Everything in life, the outer objects and beings as well as inner subjective experiences, however ecstatic it may be, are temporary, subject to the eternal law of change, transience, passing away and death. There is no permanent principle in life, nature or in the human being to which we can cling for support or which can give us eternal fulfillment. This is the nature of life; change, transience, impersonality, lack of any eternal support, and unfullfillment or sorrow are the inherent characteristics of life. Such was Buddha’s penetrating and rational analysis of life. Here also we can see that Buddha’s emphasis was on concrete, perceptible psychological nature of life rather than on higher spiritual nature.