Does Judge Posner need a new research assistant?

In his TNR review of Akhil Amar's The Living Constitution, Judge Richard Posner writes:

THE CONSTITUTION of the United States has its passionate
votaries ... as does the Bible. But both sets of worshippers face the
embarrassment of having to treat an old, and therefore dated, document as
authoritative. Neither set’s members are willing to say that because it is old,
and therefore dated, it is not authoritative. Some say it is old but not dated;
they are the constitutional and Biblical literalists. But most of the
worshippers admit, though not always out loud, that their holy book is dated
and must therefore be updated (without altering the text) so as to preserve its
authority. They use various techniques for updating. ...

[Akhil] Amar’s method of updating, which is also the one the
Catholic Church applies to the Bible, is supplementation from equally
authoritative sources. The Church believes that a Pope receives divine
inspirations that enable him to proclaim dogmas that are infallible and thus
have equal authority with the Bible. [For example] Jesus Christ’s mother
does not play a prominent role in the New Testament, but she became a focus of
Catholic veneration, and in 1854 the Pope proclaimed the dogma of Mary’s
Immaculate Conception (that is, that she had been born without original sin).
This and other extra-Biblical Catholic dogmas, such as the Nicene Creed, which
proclaimed the consubstantiality of the Son and the Father, form a kind of
parallel Bible, equal in authority to the written one, which reached its modern
form in the third century C.E.

It would not have taken that long to check, with someone who might actually know, and see if these paragraphs actually describe what "[t]he Church believes[.]"  A cautionary tale, perhaps, for those of us who think we know something about some things to not imagine that we therefore know something about all things.