My answer to this one is much simpler,
@Meow Mix
I reject this idea utterly, as does my church.
In 1713 Pope Clement XI condemned in his dogmatic Bull "Unigenitus" the proposition of the Jansenist Quesnel that "
no grace is given outside the Church" just as Pope Alexander VIII had already condemned in 1690 the Jansenistic proposition of Arnauld: "
Pagans, Jews, heretics, and other people of the sort, receive no influx [of grace] whatsoever from Jesus Christ".
Even back in the old pre-Vatican II days, there was the medieval doctrine of "
baptism by implicit desire", explained by even Pope Pius IX in
Quanto Conficiamur Moerore (1863) as follows:
“...We all know that those who are afflicted with invincible ignorance with regard to our holy religion [non-believers], if they carefully keep the precepts of the natural law that have been written by God in the hearts of men...and if they lead a virtuous and dutiful life, can attain eternal life by the power of divine light and grace.”
Cardinal Juan De Lugo (a. d. 1583-1660), Spaniard, post-Reformation Roman Catholic, Jesuit, Theological Professor, and a Cardinal writing in Rome under the eyes of Pope Urban VIII, had noted this a lot earlier:
“…the members of the various Christian sects, of the Jewish and Mohammedan communions, and of the non-Christian philosophies, who achieved and achieve their salvation, did and do so in general simply by God’s grace aiding their good faith instinctively to concentrate itself upon, and to practise, those elements in the cultus and teaching of their respective sect, communion or philosophy, which are true and good and originally revealed by God…”
(Cardinal Juan De Lugo (a. d. 1583-1660), De Fide, Disputations)
Atheists, too, were explicitly stated to be encompassed within this bracket in the Vatican II constitution
Lumen Gentium in 1964:
Lumen gentium
Nor does Divine Providence deny the helps necessary for salvation to those who, without blame on their part, have not yet arrived at an explicit knowledge of God and with His grace strive to live a good life. Whatever good or truth is found amongst them is looked upon by the Church as a preparation for the Gospel.(20*) She knows that it is given by Him who enlightens all men so that they may finally have life.
Pope St. Paul VI said the following with regards to atheists in his 1964 encyclical:
Ecclesiam Suam (August 6, 1964) | Paul VI
"...The Church can regard no one as excluded from its motherly embrace, no one as outside the scope of its motherly care. It has no enemies except those who wish to make themselves such. Its catholicity is no idle boast. It was not for nothing that it received its mission to foster love, unity and peace among men...
Though We speak firmly and clearly in defence of religion, and of those human, spiritual values which it proclaims and cherishes, Our pastoral solicitude nevertheless prompts Us to probe into the mind of the modern atheist, in an effort to understand the reasons...
They are obviously many and complex...They sometimes spring from the demand for a more profound and purer presentation of religious truth, and an objection to forms of language and worship which somehow fall short of the ideal. We see these men serving a demanding and often a noble cause, fired with enthusiasm and idealism, dreaming of justice and progress and striving for a social order which they conceive of as the ultimate of perfection, and all but divine.
This, for them, is the Absolute and the Necessary...Again we see these men taking pains to work out scientific explanation of the universe by human reasoning, and they are often quite ingenuously enthusiastic about this.
It is an enquiry which is all the less reprehensible in that it follows rules of logic very similar to those which are taught in the best schools of philosophy...They are sometimes men of great breadth of mind, impatient with the mediocrity and self-seeking which infects so much of modern society. They are quick to make use of sentiments and expressions found in our Gospel, referring to the brotherhood of man, mutual aid, and human compassion...We do not therefore give up hope of the eventual possibility of a dialogue between these men and the Church..."
The current pontiff, Pope Francis, has gone even further:
Pope Francis Meets With Muslim, Jewish Leaders, Praises Atheists as ‘Precious Allies’
Francis also extended a welcome to atheists and those who ascribe to no particular religion.
“I feel close to all men and women who, although not claiming to belong to any religious tradition, still feel themselves to be in search of truth, goodness and beauty,” he said. “[Atheists and nones] are our precious allies in the effort to defend human dignity, in building a peaceful coexistence between peoples, and in carefully protecting creation.”
Or as the Second Vatican Council's pastoral constitution
Gaudium et Spes (1965) put it:
Pastoral Constitution on the Church in the Modern Word-Gaudium et Spes
"Atheism results not rarely from a protest against the evil in this world...
For, taken as a whole, atheism is not a spontaneous development but stems from a variety of causes, including a critical reaction against religious beliefs, and in some places against the Christian religion in particular. Hence believers can have more than a little to do with the birth of atheism.
To the extent that they neglect their own training in the faith, or teach erroneous doctrine, or are deficient in their religious, moral, or social life, they must be said to conceal rather than reveal the authentic face of God and religion..."