That's why it's important to search the scripture for oneself. Teachers obviously CAN shed light and often do; however, if they contradict what's in the text...that's when a red flag goes up because political considerations or other considerations of the day can color church leaders' "interpretations". I wonder what was going on politically in the Catholic church when the Immaculate Conception was doctrinized in 1850 or thereabouts and when the Assumption of Mary was doctrinized in 1950.
As I look at that Timothy passage I become more convinced that the foundation is God...the "household" referred to in the earlier passage denotes believers; however, Paul is pointing out that the "foundation" under that household and the "pillar" which holds it up are God. Then Paul goes on to exalt in that foundation in the last verses of the chapter. Of course, as I said I would like to hear what a Greek scholar thinks about it as I don't know Greek. But the English and the Interlinear seem fairly straightforward to me.
That's a legitimate question, inasmuch as doctrine generally develops (becomes more precise and defined) under the stimulus of new questions, challenges, scientific knowledge, and of course heresies.
I don't know, but I have a hunch: what was happening at around the time that the Immaculate Conception was defined (1854)? Three related things come to mind:
(1) the human ovum was first seen in 1823; and the fertilization of the ovum was first observed, I think, a couple of decades after that.
(2) It therefore became clear, at least to the educated, that fertilization marked the beginning of every individual's life.
(3) I remember, from reading the history of anti-abortion legislation in the 19th century, that doctors who opposed abortion had to educate legislators that common "women's remedies" which "brought on blocked menses" were actually killing new babies at the embryonic stage, and 19th century prolife reformers campaigned to ban these "remedies."
This was all new stuff, and caused quite a bit of intellectual buzz back then.
I wonder whether the Pope was responding to these new scientific discoveries by reiterating that the life of Mary began at her conception, and that God, in preparing a "pure seed" (the "seed of a woman" as in Genesis 3:15) and "spotless mother" for the Incarnation. would have purified Mary (preveniently, through the merits of Christ, who is her Savior as well as ours) at the very beginning of her life, i.e. her conception.
"And I will put enmity between thee [the serpent] and the woman, and between thy seed and her seed; it shall bruise thy head, and thou shalt bruise his heel." (Genesis 3:15)
(Did you ever wonder about that odd term, "her seed"? The whole concept of a woman having a "seed" --- as in, ovum --- was completely unknown to the ancients, who generally believed that the father was the only true genetic parent, and that the woman's womb was merely a receptive "field." Hmmmm...)
If you think this historic hypothesis is dubious, you're entitled to: it's just a wild guess of mine: my hunch as to why this doctrine wasn't "defined" until 1854.
I'll send this around to some Catholic Freepers and see if any of them have an opinion on this.
Allow me to reiterate that these are just my own wackadoo speculations.