Complete objectivity is impossible. This is why Ayn Rand's Objectivism philosophy was so broken. It's not just that humans can't be completely objective -- any AI can't be either, and you can't write have a human write an algorithm that yields 100% objectivity. It can't be done. There is no short-cut. The arguments have to be had. Consensus/democracy/institutions is all we've got, and we have to and will make that work.