h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

I tend to reject the idea that there is no truth, just opinion (see my page for further details).

I think that there are statements which are truths (like the concept of 1,or 1+1 =2,or a triangle has three sides, etc)
So there must therefore be resulting falses (like no concept of 1, or 1+1 =3, or a triangle has four sides,etc)
Then mere opinions,( like Bananrama is the best band ever, sushi is the best food - which are neither true nor false, but merely reflect the speakers tastes)
Then beliefs which I think of as being opinions which we hold to be true- though can't prove them (like God exists)
Finally standards, values and mores, which may or may not arise from our beliefs.

If there were just opinions what would we think of Hitlers opinion that Jews should be killed, or a thieves opinion that he should have your TV set?
If all was opinion - how would we weigh one opinion against another ?
If we maintained that all opinion had equal weight?