What you say here is irrelevant unless you can show that the Roman Catholic church is the church of Jesus, so don't ask us to take too much for granted before you make any claims.
I agree. However, I'm not trying to prove my point, just explain it.
I cannot find any scriptures which show that the Roman Catholic church is the church of Jesus. The only ostensible evidence I can find is the claims of the selfsame Roman Catholic Church. So apart from scriptures which cannot be produced, you're asking me for evidence from the Roman Catholic church itself.
Jeus said : if I bear witness of myself my witness is not true.
So perhaps we could start by quoting that particular scripture
I know well enough that this kind of forum isn't really conducive to discussing biblical evidence. Furthermore, I'm sure any evidence I produce can be counter-evidenced or just fudged away. However, I'd basically argue on these kind of lines:
a) Jesus established a Church. - from scripture
b) Jesus' Church had authority structures, with certain offices of leadership. - from scripture and history
c) Jesus would have intended his Church (and hence the authority structures) to continue historically. - from reason
d) The Catholic Church can evidence its authority structures back to the first century. - from history
e) The Catholic Church can evidence a continuity of most dogma back to the first/early second centuries. - from scripture and history
f) The only other possible Churches that can sustain such an argument might be the Orthodox and Coptic Churches. - from scripture, history and reason
g) So, it is quite reasonable that the Catholic Church is the one started by Christ.