The subtle sound ‘parA’ cannot be heard by human ear and cannot be vocalised by human voice. It is in fact the root source, the substratum, of all sounds. When that gets a little focussed - just a little - and materialised, it becomes ‘pashyantI’.
In other words, what was ‘without purpose’ and was just plain and simple sound-root, namely, ‘parA’ , became inclined towards being heard and being spoken and so in that direction ‘solidified’ slightly and thus ‘pashyantI’ arose. So ‘pashyantI’ has a purpose!. The very word itself means ‘seeing’, ‘looking forward’. ‘parA’ had no purpose; but when the ‘purpose’ arises, it becomes ‘pashyantI’.