Why So Many Opinions?

I've wondered why it is that on just about every subject there are so many different opinions and theories when we all have pretty much the same set of facts and similar brains with which to form opinions.

Stepping aside from religion, what about things like politics and what is the best way to balance the budget?  Even among a group of people that all agree about the definition of a "good" outcome of a balanced budget, the opinions about what should be done vary.

I've also noticed that if I try to be unbiased and listen to the different viewpoints and reasoning behind them I find that most do have a sound set of reasoning.  In a way they are all logical and make sense.  Yet they cannot all be right.  So how can so many people with seemingly good rational thinking come up with so many different conclusions?

The best answer that I can come up with is that each conclusion makes sense within the context of the individual that came up with it.  That is, if you factor in someone's life experiences, their environment and the issues that they care about then often their reasoning and conclusions make sense.  The fact is however that on complex issues, or sometimes simple ones, no one human can hold in their mind every fact that is needed to come up with the true answer.  I think this is true even of things like cosmology and trying to figure out things like black holes, or dark matter.

I believe that for most things there is one true answer.  However each of us in humility must admit that we on our own cannot see the whole picture and thus our conclusion about the truth is often wrong.

This is why that any one person should not sit down with a Bible or other religious document, study it and then on their own without consultation of anyone else go enforcing their "revelation" on others.  This is exactly how we end up with wacky religious teachings and billboards giving exact dates for the end of the world.  Or you get politicians willing to send people to death over their ideology.