There's a lot of discussion going on right now about whether the Pope should lift the ban on contraception and abortion in order to help protect women from the Zika outbreak. I'm told by Catholic friends that sex that can't result in procreation and (maybe more obviously) abortion are strictly forbidden by the Church. In the case of contraception, is forbidding this more a matter of policy than doctrine? Like, heresy is still not cool, but at some point the Church said "we're not going to respond to heresy by burning people anymore". It seems a lot harder to believe that abortion could be declared okay considering it seems to be a pretty cemented doctrine that this counts as murdering a human being. Are there any examples of quick reversals in doctrine based on the Church responding to a humanitarian crisis in history? What does history tell us about the likelihood that the Pope could call for such radical changes?
Are there any examples of quick reversals in doctrine based on the Church responding to a humanitarian crisis in history?
This is a tricky question because by the instution's own definition, doctrine is an enunciation of an eternal law - a "revealed truth."
There have been changes, but those have been carefully framed as reinterpretations.
There are also practices (given the "d" name of "disciplines" to go along with doctrines, dogma and the deposit of faith) that have changed.
For instance, eating meat on Friday was once considered a mortal sin. In 1966, Paul VI declared Fridays should still be days of fasting and abstinence, but that the form of that observance "is a religious, personal act" and can't merely be "purely external."
A key bit is here:
The law of fasting allows only one full meal a day, but does not prohibit taking some food in the morning and evening, observing—as far as quantity and quality are concerned—approved local custom.
That's a little confusing - one meal, but eating three times a day?
This got further clarified nearly 20 years later in canon law:
Can. 1253 The conference of bishops can determine more precisely the observance of fast and abstinence as well as substitute other forms of penance, especially works of charity and exercises of piety, in whole or in part, for abstinence and fast.
So it doesn't really have to be about food - the food is an observance of a spiritual condition of penitence. (One rationale is that in poor nations and households, doing without food might be an everyday kind of thing, so it's not so spiritually significant a sacrifice.)
There's a consistency and a through-line there, but the execution changes as the practice is re-interpreted.
This gets complicated when a pope speaks ex cathedra (basically says, "Hey, the decider is deciding infallibly here") as Pope John Paul II did in 1994 when he said ladies couldn't be priests (Ordination Sacerdotalis). Notice that that document goes back to scripture (the deposit of faith) for its justification.
The citation of Luke 22:32 for why the pope is empowered to do this is basically him saying, "Christ gave popes the right to 'strengthen the brethren' and take hard lines on things."