It was I who mentioned homosexuality as an example of how society's attitudes can alter, which is why we should be cautious about applying our own values to the past. Of course different societies and at different times have different attitudes, and even a single society at a point in time won't agree on everything, which is why we have politics. However my point stands - history tells us it is reasonable to expect that attitudes will be different in a hundred years time, and that our own attitudes and certainties will look out-of-date and wrong.