How can I tell what is right and what is wrong? What is the measuring tool of such value statements?And moreover, by what measure are you going to use to determine whether my believe is reasonable or not?
How can I tell what is right and what is wrong?
You don't need to know how - you can tell right from wrong already!
You can tell squares from circles but you don't know how - it's basically 'circles look like circles and squares look like squares'. Your brain is wired-up to tell shapes apart and your brain is wired up to tell good and bad apart, or more accuratey wired up to judge things as being somewhere on a good-bad/right-wrong scale.
What is the measuring tool of such value statements?
i think you are asking what tool is used to determine what is good and what is bad. Well, it's not really a tool. judging thing as good or bad is a function of how you brain is wired up. Most brains are wired up to judge mugging an old lady to as a bad thing; if you have a brain wired differently you are a danger to society.
what measure are you going to use to determine whether my moral judgement belief is reasonable or not?
Note I'm answering out of the original context.
I have implied moral judgement is instinctual, that it is unconscious and outside our control. And so it is. You cannot change your opinion on capital punishment by will power alone. But what we can do is use the rational part of our brains to check, confirm or override our intinct. Being disguted by homosexuality is not a choice - refusing to bake a cake for a gay wedding is.