I agree with Matthew Allen here. This is good summing up of a rationalist approach to morality.

The key point is, that since morality is relative, we can always reserve the right to *modify* our moral thinking. This flexibility is needed for progress and social health. The societies with the most rigid morals are the most backwards and self-destructive, such as the Islamic world.

For instance, we have changed our views on things like homoexuality, slavery, racism, etc. In the not-so-distant past, homosexuality was almost universally regarded as immoral and an aberrant abomination. Now we are somewhat more tolerant, and many poeple view it as an acceptable lifestyle, even if they dont neccessarily approve of it. This saves much pain and suffering for many poeple.

Racism was regarded as a normal way of life in many parts of the country, and blacks were regarded as inferior beings. This too has changed somewhat, because we have, in part, changed our views on how all poeple should be treated, even if they are not like the majority.

What about torture, which was once believed to be acceptable? Now we have redefined, in the main, our moral stance on this. Capital punishment too has been seen in the past as appropriate, but now morally progressive regions like Europe now view it is immoral.

There are of course many other exmaples that be examined, but the point is, flexiblie morality is needed in a complex society--the old monolithic, top-down system is outdated and destructive in modern societies, as in Iran, where a women can be murdered for adultery, etc.

Morality MUST be view as relative and flexible. To view it otherwise is immoral in my view.