As
a former RC (Roman Catholic), who was born again while still a
Catholic and know from doctrine and experience, i would like to say
that the real question is how many Catholics will go to Heaven.
The
assertion that in Heaven all are Catholic is absurd. Believing on
the risen Lord Jesus Christ by His sinless shed blood to saved you
as a damned and destitute sinner is what saves, rather than partly
trusting in a church or one's own merit. True faith effects
obedience, including being part of a church as able, but the gospel of
Catholicism is one that largely preaches itself, and fosters faith in
its power and one's own goodness to save them.
As
for what they believe, this is open to some interpretation, as is
most of what Catholics believe and practice, despite claims to the
contrary.
And
by "Catholic" i presume that you mean Roman Catholics, for
while they are in "communion" with the Orthodox (and other
"Catholic"churches), they both claim to be the One True
Church in particular, and differ in not less a substantial issue as
papal supremacy and infallibility.
On
this issue the historical position of Roman Catholicism has leaned
strongly toward excluding all who were not in formal communion with
her:
Pope
Boniface VIII, Unam Sanctam:
“We
declare, say, define, and pronounce that it is absolutely necessary
for the salvation of every human creature to be subject to the Roman
Pontiff.” — Pope Boniface VIII, Unam Sanctam (Promulgated
November 18, 1302) http://www.fordham.edu/halsall/source/b8-unam.html
St.
Thomas Aquinas: It is also shown that to be subject to the Roman
Pontiff is necessary for salvation. St. Thomas Aquinas, Against the
Errors of the Greeks, Pt. 2, ch. 36
http://dhspriory.org/thomas/ContraErrGraecorum.htm#b38
…that
no one, whatever almsgiving he has practiced, even if he has shed
blood for the name of Christ, can be saved, unless he has remained in
the bosom and unity of the Catholic Church.” Pope Eugene IV,
Cantate Domino, Bull promulgated on February 4, 1441 (Florentine
style), proclaimed “ex cathedra” (infallible).
The
Holy Catholic Church teaches that God cannot be adored except within
her fold; she affirms that all those who are separated from her will
not be saved. (Pope St. Gregory the Great, “Moralia,” XIV:5)
However,
Rome has infallibly decreed that she is infallible (conditionally)
and cannot change, and can define what she meant as needed.
Thus
the RC Catechism (RCC: 846) states, 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:…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
The
"through no fault of their own" clause is what is debated
among Catholics, as Rome has not definitively clarified her ambiguity
as to whether it excludes such souls as Protestants who known of the
claims of Rome but "through no fault of their own" believe
such Catholic claims are unwarranted, but these Protestants obey the
light they have, or if it only refers to those who are ignorant of
the claims of Rome, but obey the light they have.
In
addition, even the second condition is open to interpretation as to
whether it means that such will come to accept the Catholic church as
a consequence of obeying the light they have, or whether those
"through no fault of their own" who are ignorant of the
Catholic church, or the gospel of salvation, can be saved.
The
latter encounters a further problem in that Scripture indicates
that outside souls who are not mature enough to make moral choices,
(Is. 7:15,16) ignorance of truth is our fault, and that by obeying
the truth we have then we will come to the Truth of salvation.(Mt.
13:11,12; Rm. 2:7; Acts 10)
In
favor of Protestants being able to saved who know the claims of Rome but reject them in good conscience are the words of Vatican Two
(which Traditional Catholics impugn or reject as being hijacked by
liberals),
LUMEN
GENTIUM: 16; The Church recognizes that in many ways she is linked
with those who, being baptized, are honored with the name of
Christian, though they do not profess the faith in its entirety or do
not preserve unity of communion with the successor of Peter. (Cf.
Gal. 4:6; Rom. 8:15-16 and 26)
For
there are many who honor Sacred Scripture, taking it as a norm of
belief and a pattern of life, and who show a sincere zeal. They
lovingly believe in God the Father Almighty and in Christ, the Son of
God and Saviour. (Cf. Jn. 16:13) They are consecrated by baptism, in
which they are united with Christ. They also recognize and accept
other sacraments within their own Churches or ecclesiastical
communities.
They
also share with us in prayer and other spiritual benefits. Likewise
we can say that in some real way they are joined with us in the Holy
Spirit, for to them too He gives His gifts and graces whereby He is
operative among them with His sanctifying power. Some indeed He has
strengthened to the extent of the shedding of their blood..
[Note:
Rome does not refer to Protestant church as churches but
"ecclesiastical communities," while she herself is guilty
of shedding their blood because they obeyed in conscience toward God
they obeyed light of Scripture.And the fact that Rome stipulate
baptism evidences that it is not merely affirming salvation by
obeying the limited light one has, but that she recognizes that Prots
can be saved by believing the gospel and which saving faith is
expressed in baptism, and which regeneration can take place before
the person knows of or joins a church as seen in Acts 8, 10, etc.]
LUMEN
GENTIUM continues,
But
the plan of salvation also includes those who acknowledge the
Creator. In the first place amongst these there are the Mohammedans,
who, professing to hold the faith of Abraham, along with us adore the
one and merciful God, who on the last day will judge mankind.
This
portion in particular is troubling because it affirms Allah is the
God of Abraham, which is blasphemous, as they are manifestly not the
same. Nor is this the case of worshiping an unknown God as in Acts
17:23, but is a case of "identity theft" by Islam.
In
addition is the inference that Muslims etc. can be saved apart from
believing the gospel Christ in this life, due to ignorance thru no
fault of their own and acting in good conscience, which many Prots
wrestle with as well, (see Rm. 2) though it is clear that "Neither
is there salvation in any other: for there is none other name under
heaven given among men, whereby we must be saved. " (Acts 4:12)
