Sometimes these questions get mixed up with others: for instance, an atheist recently asked me if it was true that the Catholic Church says everyone who's not a baptized Catholic is automatically going to Hell. Luckily, the Catechism explains this teaching quite fairly; I recommend a careful reading of this entire section from 811 to 870, but the specifics are spelled out in 846 and 847, as follows:
rejected despite understanding of the mind and heart and freedom of the will, the consequences to the soul may indeed be dire.
846 How are we to understand this affirmation, often repeated by the Church Fathers?335 Re-formulated positively, it means that all salvation comes from Christ the Head through the Church which is his Body:
Basing itself on Scripture and Tradition, the Council teaches that the Church, a pilgrim now on earth, is necessary for salvation: the one Christ is the mediator and the way of salvation; he is present to us in his body which is the Church. He himself explicitly asserted the necessity of faith and Baptism, and thereby affirmed at the same time the necessity of the Church which men enter through Baptism as through a door. Hence they could not be saved who, knowing that the Catholic Church was founded as necessary by God through Christ, would refuse either to enter it or to remain in it.336
847 This affirmation is not aimed at those who, through no fault of their own, do not know Christ and his Church:
Those who, through no fault of their own, do not know the Gospel of Christ or his Church, but who nevertheless seek God with a sincere heart, and, moved by grace, try in their actions to do his will as they know it through the dictates of their conscience - those too may achieve eternal salvation.337
And so the Church has always taught that a place of eternal separation from God which we call Hell does indeed exist; she does not teach that it would be better for people to cease to exist given that our immortal souls are an intrinsic part of us; and she also does not teach that God sends people to Hell--rather, Hell is a free, if terrible, choice of individual souls who, knowing that God is and discerning how He wishes to be followed, worshiped, and loved, choose freely and willingly to reject Him forever, through the actions of their lives and up to and including at the moment of their deaths.
One of the many discussions that take place concerning Hell is: is Hell rather crowded, as Dante envisioned it? Is it rather empty, as Origen and others speculated? Can we guess, from the names of the historically infamous, who might be there?
The truth is, all of those speculations are rather profitless, and the third may even be spiritually dangerous. We must, as Catholics, believe that Hell exists (where else would the fallen angels be, in a metaphysical sense, than the Hell that is eternal separation from the God whom they knowingly and freely rejected?) and that people are free to choose to remain so steeped in their own freely-chosen sins and rejection of God that they may choose Hell as well. But the thought of Hell should never be grounds for smugness; none of us is guaranteed Heaven, either, and we should be begging God daily for mercy for all sinners, chief of whom is our own self.
This, unfortunately, brings me to a realization: there are Christians, and even some Catholics I've encountered, who seem to exhibit an unholy glee (if you'll excuse the expression) when they talk about Hell, and the sinners who they think are going to end up there (not themselves, of course, but practically everyone else they know). It is almost as though they think of Hell as the ultimate revenge--theirs, not God's, even if they won't admit it--to be enacted upon anyone who has disagreed with them or caused them pain or embarrassment in their lives. Some of them will speak of the eternal destiny of whole groups of people who don't belong to their particular Christian sect (and Catholics are sometimes among those eternally predestined for hellfire and damnation) with a kind of placid shrug, a glinting eye, or a grin wholly at odds with the serious nature of what it is they are talking about. "Sure, the Smiths are a nice family. Too bad they don't belong to the First Saved United Church of Christian Fellowship of Third Street. It's just too sad to think of them all burning in Hell, isn't it? Pass the mashed potatoes, please."
But while that last bit may be an exaggeration, it's true that in talking about Hell many of us Christians have the unfortunate tendency to sound more like an alarmist spinster aunt warning of the evils of television or rock music than like concerned brothers and sisters trying to warn our dear ones on the road to perdition that they are headed in the wrong direction, that the bridge is out up ahead, and that we hope they'll at least consider putting on the brakes long enough to inspect the situation for themselves before deciding they never believed in the right direction, the bridge, the gorge, or the volcano below in the first place. It's like the old joke about the pastor who delivered the following homily, in three sentences: 1. Millions of people may be going to Hell. 2. Far too many of you sitting here in the congregation today don't give a damn about that. 3. In fact, most of you are more upset that your pastor just said "damn" in church than you are about the millions of people who may be going to Hell.
(Which would, of course, be an awesome homily to hear--but I digress.)
Our response to the Church's teaching about Hell should be to try to live our lives in accordance with God's holy will, to avoid sin and especially to root out those habits and tendencies of serious sin which might place an insurmountable barrier between us and God, and to pray for and trust in His Divine Mercy without either giving into despair on the one extreme, or presumption on the other. If we want to help lead others in the direction we hope we are going, we will do so much better by trying to become heavenly creatures ourselves than by telling them in detail why they are hellish ones--and, of course, by making their eternal salvation a priority in our prayers, and begging God to shower them with even greater oceans of His holy mercy than those we hope will wash away our own sinfulness.