Well, if canonizations are infallible, then St. Thomas is in Heaven right now, correct?  And, he taught Baptism of Desire, right?  Besides, why would he be elevated to the status of a Doctor of the Church if he held to heretical ideas??

St. Thomas Aquinas taught more than one false doctrine.  See for yourself.

Of course!

Very good, you recognizae that Aquinas was fallible.

And, he is still in Heaven, right?

Well, as I said before, canonizations are not infallible.  As imprudent (and censurable) as it is to say he is damned (I make no such assertion), it is entirely possible that this could be the case, and it is not heretical to say so.  just ask Benedict XIV (14), who explicitly states that asserting a pope had erred in this or that canonization may not be heresy (indicating he didn't really know if they were infallible or not).  If he were aware of the decree of the Vatican Council, he would have simply said, "even though not a heretic," rather than "if not a heretic,".

So if BoD/BoB are false, then we err in good faith, just as you do if both doctrines turn out to be true.

No.  That is not a valid excuse.  A person is bound to judge externals, the objective facts.  We cannot look into hearts, though we can be given a good indication of the disposition of someone by their external acts, eve moral certainty, we can never know with absolute certainty.

Now that being said, the externals we must judge are that the pope saw fit to canonize St. Thomas.  This means the he did not find any heresies, or that he did not recognize any heresies in his writings.

Even if there had been heresies in the works of a particular person who was canonized, the canonization itself is not a promulgation of such works, and it is also entirely possible that these works were not know until a later period.

And you could not argue that this made the pope a heretic, because he never taught or publicly expressed the heretical opinion.  You would be jumping to schismatic conclusions, by implicating a pope for a heresy he never expressly acknowledged, or taught.

Furthermore, something is only heretical if it contradicts something that is already a dogma of the Faith.

Many Thomistic proposition, which are not heretical, were not in his day and were allowable, however erroneous, opinions.

To say that he may have "erred in good faith" is nowhere near as far fetched as to say that "you have erred in good faith".

Why?

Because now, we have the definitions of the Vatican Council telling us exactly how we are to understand infallible decrees (exactly as they are declared, and with no recession from the meaning of such a declaration).

Besides, because, unlike Aquinas, or anybody who lived during the first six thousand years of the world's existence, we can instantly access ANY and EVERY (almost anyway) Church docuмent, papal writing, etc.

You have seen the decrees of the Vatican stating we must believe and hold the meaning that was declared in the definition itself, and is irreformable, and the teaching Pope Leo XIII, stating that to recede even slightly from any point of doctrine proposed by the authoritative Magisterium causes one to be not a Catholic, and the teaching of Pope Pius X, which states that the dogmas are truths which have fallen from heaven (absolute, objective, transcendental truths, not wishy-washy semi-truths, or half truths).

If you still refuse assent to the very obvious and objective sense of a dogmatic decree, you are not doing so in good will.  You are disobeying three clear commands by the Pontiffs, whereby the tell you exactly what you must believe FOR SALVATION and how you must believe it.

OH NUTS!!!

Many Thomistic proposition, which are NOW heretical, were not in his day and were allowable, however erroneous, opinions.

 :smash-pc: