Nasadiya Sukta found inn Rig Veda (chapter X 129) is a hymn in seven verses ascribed to Prajapati. The Sukta is associated with creation of the world. The name of the sukta is Nasadiya because the hymn is beginning with Nasada. It is a bhavavritta (Brihaddevata 8. 45-46), i.e., an account of becoming, as given below:
In the beginning, this universe was neither existent nor non-existent. There was neither the atmosphere, nor the heaven beyond, no substratum and so nothing to cover, no death, no immortality, nor any sign of night and day. It was darkness hidden by darkness.
Perhaps there was impervious primeval water – an indistinguishable, all pervasive fluid. That One, arising through the power of tapas, breathed without air by His inherent power.
First, desire came into being as the seed of the mind. Searching in their heart through the power of the mind, the wise ones have found out the bond of existence in the non-existent. And that bond has spread everywhere.
But all this is unknowable. The omniscient One above may know or may not know.
The earliest expression of the evolutionary theory is that of the Samkhya philosophy, but this hymn tentatively hypothesizes the all pervasive fluidity from which the mind first evolves. Similarly, the first evolution – of ‘intellect’ (buddhi) from undifferentiated matter – is without an agent. But unlike in Samkhya, “that One” (presumably a conscious principle) breathed without air before creation. Again, the doubt expressed about omniscience finds its echo in the rationalist stand taken on this by Kumarila (7th century CE, Slokavarittika on Mimamsa Sutra I.1.2). Its literary merit, is spirit of enquiry as opposed to dogma, and the boldness of philosophy are distinguishing makrs pointing to it also as the beginning of natural philosophy.