"There is a physical difference between the white and black races which I believe will forever forbid them living together on terms of social and political equality."
That quote is not from a Ku Klux Klan grand wizard or Hansonite mouth-breather but US President Abraham Lincoln, the man credited with the abolition of slavery in that country and considered one of the great progressive thinkers of his time.
Taken from an 1858 debate, it shows how even the most enlightened minds of an era can seem horribly backwards to us folks who arrive later on the scene.
You don't have to go far to find similar examples in contemporary Australia, such as PM Tony Abbott questioning whether women have the "aptitudes, abilities and interests" for leadership. Or, perhaps, Julia Gillard's craven double-speak for her not-supporting gay unions because she considers marriage to be an oppressive patriarchal institution.
These are obvious, morally unjustifiable stances about which many people already shake their heads, yet there are undoubtedly other widely-accepted beliefs that will one day cause our children and grandchildren to cringe with embarrassment knowing we ever held them.
It's already evident there will be future recriminations about hateful societal attitudes towards women, homosexuals and the disabled but what are the other - "nose on our face" - issues we're totally blind to?
A couple of weeks ago on the ABC's Q&A, conservative British author Peter Hitchens made the observation that day care and nannies for children may one day be considered indefensible.
"Future generations will look on our treatment of children as we look on the Victorians for sending children up chimneys. They will be amazed at the cruelty and neglect that we shared to our children when we were so rich," he said.
Hitchens seemed to be using this statement to bolster a world view in which women should return to the home and child-rearing, but his gender demarcation is no less black and white than that of our courts, which in the majority of cases still insist young children are better served having a woman as their primary carer when custody is in dispute.
People get very defensive when the status quo of child-rearing is challenged but it's a fact humans have gotten it horribly wrong for millennia - beating kids, emotionally abusing them, sending them to work in dangerous conditions, using them sexually, killing them if they're the 'wrong' sex, selling them into slavery and warping their minds with religious, racial and nationalistic beliefs they have no choice but to accept.
Rejection of all of these practices is by no means global, which shows you the zeitgeist moves at different speeds in different cultures.
However, in the liberal west, where moral sympathy has arguably extended furthest to women, homosexuals, minorities, the disabled and to animals, we now accept a 'new reality' of day care for children as young as three months and regularly farm out our kids' formative years to paid professionals.
It's considered retrograde to suggest this task should be re-shouldered by women now rightly viewed as equals in the workplace, yet the laws of our land still enshrine the primacy of the mother.
It makes me wonder if we'll one day be shaking our heads at the offensiveness of saying a "woman is a more natural carer than a man" as we do now when someone suggests females lack aptitude for leadership.
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