While I was doing research for "The Ordinary and Universal Magisterium", I came across some amazing passages in the New Advent Catholic encyclopedia's article on infallibility. Since it can be safely assumed that these still represent the Catholic church's viewpoint, I thought it was worth calling some wider attention to them.
The article starts out by making the same threats that are endemic to all forms of Christianity: the ominous proclamation that the church is infallible, and if you don't believe what they tell you to believe, you face an eternity of torment:
...the Church is entitled to claim infallible doctrinal authority. This conclusion is confirmed by considering the awful sanction by which the Church's authority is supported: all who refuse to assent to her teaching are threatened with eternal damnation.
(I like to imagine the pope holding a flashlight under his chin while he says that. Woooo, spooky!)
Now, as I mentioned in the previous post, the church doesn't claim that all its teachings are infallible, just the ones that it says are infallible. But from the standpoint of the ordinary man or woman in the pews, it doesn't matter, because the church says that the penalty for rejecting any church teaching, whether claimed to be infallible or not, is the same. Disbelieving anything the church commands you to believe is a mortal sin, and those who die with a mortal sin on their souls, etc., etc. The New Advent article acknowledges this:
...[T]he same penalty is threatened for disobedience to fallible disciplinary laws or even in some cases for refusing to assent to doctrinal teaching that is admittedly fallible.
The obvious rejoinder to this is that it proves the church's allegedly God-given authority is a sham, because in the past they've demanded that people give their assent to claims which even the church now admits are false. The most obvious case, of course, is when a church tribunal censored Galileo's writings, threatened him with torture and consigned him to house arrest for teaching that the Earth orbits the Sun. And the New Advent article acknowledges this, but the apologetic they propose is truly staggering in its delusional arrogance:
...in the Catholic system internal assent is sometimes demanded, under pain of grievous sin, to doctrinal decisions that do not profess to be infallible. [But]... the assent to be given in such cases is recognized as being not irrevocable and irreversible, like the assent required in the case of definitive and infallible teaching, but merely provisional; and in the next place, internal assent is obligatory only on those who can give it consistently with the claims of objective truth on their conscience - this conscience, it is assumed, being directed by a spirit of generous loyalty to genuine Catholic principles.
To take a particular example, if Galileo who happened to be right [who "happened" to be right? —Ebonmuse] while the ecclesiastical tribunal which condemned him was wrong, had really possessed convincing scientific evidence in favour of the heliocentric theory, he would have been justified in refusing his internal assent to the opposite theory, provided that in doing so he observed with thorough loyalty all the conditions involved in the duty of external obedience.
What this means, if I read it right, is that Catholics are required to believe everything the church tells them to believe - unless they know for a fact it's false, in which case they can secretly withhold their assent. But even so, they're still required to act and speak as if they believe the thing they know is false, and they're still required to obey any command the church gives that's based on that falsehood, which may include a decree of censorship ordering them to never discuss the thing they know is true or even to destroy the evidence that shows it to be true.
And if the church issues an ex cathedra proclamation, even that option of completely ineffectual resistance is taken away. Anything that's taught infallibly, Catholics aren't permitted to doubt, even inwardly. They're required to believe it wholeheartedly and that's that, and if they don't, they put themselves at risk of eternal damnation.
The church's claim of absolute authority over the lives and even the inward thoughts of its members shows how far it hasn't come. In fact, its mindset hasn't really changed at all from its medieval, theocratic past - the days when it really did have the power it now only believes it has, when it could compel governments to obedience and threaten heretics with torture and death. Inside the Vatican, it's as if time has stood still for centuries: the church's rulers dwell in faded citadels surrounded by memories of past empire, and still delude themselves that they command the eternal destiny of the world. They're welcome to live their lives in dreams of the past if they wish, but when they venture out into the present day and pompously proclaim their superiority over the rest of us, the only response they should get is the laughter and scorn they so richly deserve.