Now and then in discussions online, I run into the "in X years, your position will be considered vile!" claim.
In 50 years, history will look back on your opposition to gay marriage as putrid and hateful! is one common claim. Sometimes it's 20 years. Sometimes it's 50. Almost always it's measured in decades, or even centuries.
I think part of the imagined force of this argument comes from a mistaken translation of scientific progress to moral progress. Skeptics of the Wright Brothers and the ability to fly turned out to be wrong, entirely wrong, and that's not going to change. Skeptics of rocket technology? Likewise. They were wrong at the time, they're wrong 50 years later, and they'll be wrong arguably for all of time.
That's the unspoken assumption that comes with these proclamations of society eventually and overwhelmingly regarding such and such moral claim as wrong: it's not just that in 50 years a lot of people think you're wrong and that your position is immoral. It's that in 50 years, and unto eternity from that point on, your view will be regarded as wrong and immoral.
The first problem is, at least for me... I really do not give a shit whether the whole of the sentient universe, at some arbitrary but past-my-life point in the future, believes that the position I take on such and such is immoral and wrong. I'm concerned with objective morality, the will of God and my eternal life. If George fucking Jetson regards my views on abortion with shock and horror, it's of little concern to me. The very idea I should care is alien. Now, if I'm wrong about objective morality, the will of God or on an issue that may affect said afterlife, well then, that's a concern to me *right now*. You don't to bring the Jetsons into this at that point - they remain moot.
The second, and arguably larger problem, is that the claim requires moral views to be evaluated like scientific claims - and every indication is that it's a mistake to think of moral claims this way. Even wannabe 'scientific moralists' like Sam Harris are forced to realize that, at the end of the day, their talk of morality is extraordinarily reliant on fundamental arguments, axioms, and reasoning that is ultimately rooted in philosophy and metaphysics (in principle) or emotion and self-interest (in practice). While the gates of hell may not prevail against the Church, history says it can prevail against the rest of the world just fine. Really, it's far more surprising when those gates DON'T prevail.
The short of it is, even if my view is universally regarded as wrong in 50 years, in 100 years or 1000 years the lay of the land may change yet again. In fact, change 'may' to 'likely will'. If someone isn't particularly upset that their views will likely be on the moral outs with society at some undetermined point(s) in the future, why should I care that my view may be in the same position at some arbitrarily distant point in the same future?
So really - the shifting culture of the arbitrary future is not a concern to me, and I wonder if anyone who does care about it is really thinking it through.