Actually Rig Veda is far older then 1500BCE.
Only according to a Hindu version of world history.
Actually, I don't have a problem with dating the 'Rig Veda' to ~2000 BCE if you want, and Moses' transcriptions to ~1500 BC.
From the Bible we have: God's Creation, the Flood (5000 BC to 2400 BC, depending on one's interpretation of the meaning of 'begat'), Tower of Babel (3000 BC to 2100 BC, again depending on one's interpretation), dispersion of the peoples (cousins -- which we call 'races'), and then God giving the Law to Moses around 1500 BC (where Moses then transcribed the first 5 books of the Bible).
So sure, there could have been many things written before 1500 BC (e.g., the Babylonian tale of Creation: Enuma Elish; etc), but Scripture IS Scripture.
Only HIS Word IS God breathed, and standeth forever, and is alone worthy to be a lamp unto our feet and a light unto our paths ("All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness...").
Classic case of circular arguments:
“What’s the proof that the Scriptures were written in 1500 BC?”
“The Scriptures mention the dates to be around 1500 BC.”
“Whats the evidence that the Scriptures are God’s word?”
“The Scriptures say that IT IS the God’s word.”
Max Muller was a Christian who believed the world was created at 9 am 23 october 4004BC and he adjusted other chronological events accordingly to comply with his Christian world view.
BTW read on books written by David Frawley and Koenraad Elst on Veda. Note: Neither of them are Hindus.