There is hardly any Hindu who does not regard the Vedas as the most sacred book of his religion.And yet ask any Hindu what is the origin of the Vedas and it would be difficult to find one who can give a clear and definite answer to the simple question. Of course if the question is asked to the Vedic Brahmin he would say that the Vedas are Santana. But this is no answer to the question.
The best explanation of the word Sanatan is to be found in the commentary by Kulluka Bhatt on chapter 1 shlokas 22-23 of the Manu smriti.This is what the Kulluka Bhatt defines the word Sanatan:
"The word sanatan he says, means' eternally pre-existing'.The doctrine of the superhuman origin of the Vedas is maintained by Manu.The same vedas which (existed) in the prevbious mundane era(kalpa) were preserved in the memory of the omniscient Brahma,who was one in with supreme spirit. It was those same vedas that, in the beginingof the present kalpa, he drew forth from agni, vayu and surya and this dogma which is founded upon the veda is not to be questioned, for the vedas says, 'Rigveda comes from agni, the yajurveda from vayu, and the samaveda from the surya".
To underastand the explanation byKulluk Bahtt , it is necessary to explain what Kalpa means.
A kalpa is a reckoning of time adopted by the vedic Brahmins. The Brahminic reckoning of time devides time in to1. Varsha. 2.Yuga. 3.Mahayuga. 4. Manavantara. 5.Kalpa.
Varsha is easy enough to understand. It corresponds the term year.
What exactly the time of period covered by the term yuga covers , there is no unanimity.
A Mahayuga is a period covered by a group of yugas1.Krita.2. Treta.3. Dwapar. and 4. Kali yuga.The four yugas follow one another in a cycle, when the period of the first yuga is spent it is followed by the second yuga and so on in the order given. When the cycle is complete one Mahayuga begins with the Krita yuga and ends with the Kali yuga.
There is no uncertainity as to the time relation of Mahayuga and a Kalpa.71 Mahayugas make one kalpa.
The idea underlying the Kalpa is closely connected to the creation and the dissolution of the universe. The creation of the world is called srishti. The dissolution of the universe is called pralaya. The time betwwen the srishti and the pralaya is called Kalpa.The idea of the origin of the vedas is thus more intimately connected to the idea of Kalpa.
According to this scheme of thing , what is supposed to happen is that when a kalpa begins creation begins. With the begining of the creation there come into being a new series of vedas. What Kulluka Bhatt wants to convey is that though in a sense every new kalpa has a new series of vedas, the same old vedas are reproduced by Brahma from his memory.That is why he says the vedas are sanatan, that is eternally preexisting.
What Kulluka Bhatt says is that the vedas are reproduced from memory.The real question is who made vedas and not who reproduced them. Even if one accepts the theory of reproduction at the begining of each kalpa the question still remains who made the vedas when the first kalpa began. The Vedas could not have come into being ex-nihilo. They must have a begiming though they may have no end.Why do not the brahmins say openly?Why this circumlocution?
(From chapter 2, Riddles in Hinduism, an exposition to enlighten the masses by Dr. B.R.Ambedkar, Dr. Babasaheb Ambedkar's writings and speeches ,Vol.4 )
-Dr.Chikte