I would point to some genuine cultural changes for the better in the last three hundred years. For one thing, slavery became a thing to be abolished--even if the job is not yet complete nor is it something that might never happen again. For another--casual racism has become something a large chunk of the world finds so distasteful bigots have to use code words in common, yet protection against such prejudice is enshrined into law. A far cry from the utterly unashamed presumptions of ethnic superiority and open anti-Semitism that were the norm in 1800 for example. Ditto our attitudes towards the genders. To be sure, we haven't become utopia--but 150 years ago the general attitude towards the poor (for example) was to blame them for being poor, with the "solution" put into effect was to humiliate and punish them. Sadly those attitudes are still with us, but they are anything but universally accepted as wisdom these days. While I think a few centuries is not enough to really change the fundamental nature of humankind, socially it is a very difficult argument to make that we never "grow up" or mature as a society, with a civilization's members growing up in a better moral environment as a result.