Dear Member (ThinkingOne)

After you have mentioned the link, Ii read it. Four Jug are concepts in Hindu mythology. Guru Sahib had no alternative but to start imparting learning from where the frame of minds of his audience was. The dominant culture has given them this frame of mind. For this reason Guru Sahib has used the terms which were prevelant in public perception in his time. Use of these concepts by Guru Sahib is not the endorsement of the concept proper, it was a required for effective communication; and there it ends.
Reference:: Sikh Philosophy Network http://www.sikhphilosophy.net/jap-ji-sahib/449-japji-sahib-pauri-7-a.html

Toady we know no one can live for four Yugas. Nature has not designed the body to live for that long duration - practice of Yoga or not.

Every day since birth, on the average the individual looses 5000 neurons in the brain, dead neurons donot get replaced, one has to live with this deficit. In early age, the impact of this loss is not evident but when the man crosses 50 years of life he himself starts finding difficulties with his memory etc and after 60 years it becomes so evident that even others can make out. For women this happens at much later age; because their brain is structured in a different way and the link that connects the two halfs of the brain is much thicker when compared to that of men.
Reference:: Sikh Philosophy Network http://www.sikhphilosophy.net/showthread.php?t=449

You know that brain controls the body, when it itself starts degeneration after 50 - 60 years or so, how can body survive for four Yugas; it is only a mythological concept. If one reads Bhagavatam (it is not Gita) in the initial part it says that some mythological kings ruled the earth for few thousand cores of years but in the latter part says that human life is around 100 years.

With love and Respect for all.

Amarpal