Theory/technicality vs practice.  It's a common distinction.  Both are right, from a certain point of view. 

Technically - Polar Bears are not white.  Their skin is jet black and their fur is translucent, which appears white because it reflects the snow.
Practice - Polar Bears appear white.

Both are true, from a different point of view.

I'm sorry you are incapable of looking at things from multiple perspectives.  The problem is not with the facts; the problem is with YOU.

This distinction between indelible mark (sacramental catholic) vs actual catholic in good standing (Faith practicing catholic)....it has been explained about 1,000x on this site.  And about 50x just in the last 2 days.  I'm glad people finally "get" what we've already said.

It's theory vs practice.
How is what he said "sanity" when he said the exact same thing as I did, just using different words?

  Just because you didn't understand HOW we explained something, doesn't mean we were wrong.

Actually, only those are to be included as members of the Church who have been baptized and profess the true faith, and who have not been so unfortunate as to separate themselves from the unity of the Body or been excluded by legitimate authority for grave faults committed. - Pius XII

Please post the link where you and Stubborn explained that a Catholic can be separated from the Church (and therefore no longer be a member/Catholic). 

I don't recall any such post.

Major - Only Catholics can receive the indelible marks of the sacraments.
Minor - Even heretics and schismatics still retain their indelible marks.
Conclusion - Heretics and schismatics are still catholic (in theory) because they retain their indelible marks and they can become catholic again in a split-second of repentence.

This is the theory/technical answer.

The practical answer is...obviously a heretic/schismatic is not a catholic, because they don't practice the Faith.

Theory vs practice.  It's a true and legitimate distinction.  You can argue all you want, but the technical definition does not change.

“Heretics and schismatics are still catholic (in theory) because they retain their indelible marks and they can become catholic again in a split-second of repentence.

This is rich! The guy can’t even see the contradiction in his own sentence.

Major - Only Catholics can receive the indelible marks of the sacraments.
Minor - Even heretics and schismatics still retain their indelible marks.
Conclusion - Heretics and schismatics are still catholic (in theory) because they retain their indelible marks and they can become catholic again in a split-second of repentence.

This is the theory/technical answer.

The practical answer is...obviously a heretic/schismatic is not a catholic, because they don't practice the Faith.

Theory vs practice.  It's a true and legitimate distinction.  You can argue all you want, but the technical definition does not change.

Let me help you out here….

Major - Only Catholics have received the indelible marks of the sacraments.
Minor - Even heretics and schismatics retain their indelible marks.
Conclusion - Heretics and schismatics are not Catholics because they don’t profess the True Faith, but because they retain their indelible mark of baptism they can become Catholic again if they repent and once again profess the True Faith.

I'll log in for just a second to help out here.  I've been having this argument with Stubborn for many years.

Problem here is the equivocal use of the term "Catholic".

That Luther remained Catholic simpliciter, nego.  That Luther remained Catholic secundum quid, concedo.

Basically, those who have the indelible mark of Baptism remain Catholic in potentia but not in actu.  This remaining Catholic "potentially" does not translate to his having remained Catholic actually.

Finally, what's really at issue isn't his loosely having remained "Catholic" (in some sense not yet defined here in this argument) but about the criteria for membership in the Church.  When I argued with Stubborn, I held that no Catholic theologian has ever held that the Baptismal character alone sufficed for membership in the Church.  I was mistaken.  In his thorough survey regarding the theological history of membership in the Church, Msgr. Fenton pointed out that one theologian held this position, but it pretty much died with him.  There are also a small handful that maintained, for instance, that occult heretics lost membership in the Church, but that opinion too was almost universally abandoned.

After Trent and St. Robert, nearly all theologians held that the requirements for membership in the Church included:  1) Baptismal character, 2) profession of the true faith, 3) formal subjection to the Supreme Pontiff, 4) not having been (justly) excommunicated.  According to St. Robert, and pretty much everyone after him, those who lack even ONE of these criteria were not members of the Church.

So, remaining a Catholic "in potency" is why (in some cases .. not all) a heretic may approach the Sacrament of Penance.  Now, this individual of course would be absolved of the SIN of heresy, especially if the heresy had never been manifest in the external forum (i.e. remained occult).  Returning to the Church, depending upon the notoriety of the heresy, might tacitly entail a restoration of professing the faith (see criterion #2 for membership), but in other case (with greater notoriety), a public profession may be required to restore membership in the Church.

So, St. Robert, likening the Baptismal character to a brand (say, on a sheep) states that once the sheep has been separated from the fold, the brand (mark) simply indicates that the sheep USED to belong to the fold, even if it's no longer actually a part of it.  Now, the owner, by virtue of this brand, can still claim legal de jure ownership of the sheep, but it doesn't change the fact that it's now de facto no longer actually part of the fold (yet another distinction here).  Now, with the discovery of modern science, we can liken the character to DNA.  If a part of your body (say, a finger) gets chopped off, it's no longer part of the body, but the DNA indicates that it used to belong to the body and used to be part of the body, but now that it's been separated from the rest of the body, it is no longer in a position to be kept alive by the body's animal soul, and is therefore severed.  It can no longer function as part oft he body, while retaining this characteristic that identifies it as having once been part of it.

As for its concrete application to the pope question, we don't really know why Cajetan, for instance, held his deponendus position, i.e. whether he believed that there could be some partial membership in the Church or whether he believed that being Catholic in potentia (in potency) sufficed to retain jurisdiction in the Church.

Now carry on.

Bottom line here is that no one is defining the term "Catholic" being thrown about or making the proper distinctions regarding the term.

Being "Catholic" in some loose sense vs. membership in the Church.
Being Catholic simplicter vs. secundum quid.
Being Catholic in potentia vs. in re.
Being Catholic de jure vs. de facto.

Theory vs practice. 
Potentially vs actually.  

Same thing I’ve been saying.  

QVD has a problem because he hates distinctions and likes everything black n white.  Which is why he likes straight Sedevancantism and is opposed to any nuance of the idea (ie sedeprivationism…human/govt papal office vs spiritual papal office).  For him, everything is ‘either-or’.

It’s probably the root cause of 50% of the debates on this site.  1) Lack of distinctions and 2) those who vehemently oppose all distinctions.  

QVD has a problem because he hates distinctions and likes everything black n white.

In this case, though, I see where he's coming from.  If you make the statement that Luther remained a Catholic (despite his heresy, excommunication, etc.), that WILL be misinterpreted and could cause scandal, since no one will be thinking of the distinction that he remains somehow potentially or de jure Catholic.  That sounds like a categorical statement and you just can't say stuff like that.  He's right that, taken at face value, the statement is absurd, extremely erroneous, etc.  While I've struggled with getting Quo to understand distinctions at times, Stubborn is utterly impervious to them, and he does more damage to his cause by making ridiculous categorical statements that are at times objectively heretical.