Let’s be quite clear on a few matters. First, the Catholic Church has never changed any defined doctrine or anything else that is part of the deposit of faith. Disciplinary matters—such as priestly celibacy and abstaining from meat on Fridays in Lent—can and do change, but these items are not part of the deposit of faith. The Church may change or dispense with these matters as it sees fit.
For changes in Catholic teaching to be grounds for accusations of false religion, those changes necessarily would have to involve a contradiction between two infallibly defined propositions. This simply has not happened in the Church’s entire history, just as Christ promised (Mt 16:18).
Now, in the Jehovah’s Witnesses’ New World Translation Bible, Proverbs 4:18 reads, “But the path of the righteous ones is like the bright light that is getting lighter and lighter until the day is firmly established."
A close look at the preceding verses shows that the passage is contrasting righteous people with wicked people. The “path" in this context refers to their respective lifestyles or life situations, not to the development of doctrine as the Watch Tower Society (WTS) would have us believe.
The “bright light" represents the righteous person becoming increasingly obedient to God’s commands and living a virtuous life. There is no warrant whatsoever for claiming this passage deals with an increased understanding of Bible prophecies.
Second, what the WTS calls “refinements" or “adjustments" are in actuality instances of it having made false predictions or having taught false interpretations of Bible passages. When this fact comes to light (no pun intended), the WTS scrambles to disguise these blunders, alleging that its understanding was not fully developed and thus needed an “increase of light."
In other words, when the WTS changes a doctrine (by reversal, flip-flop, or outright elimination) or when it wants to slough off a false prophecy, it asserts that “new light" has been received and has enabled it to better “understand" a teaching or prophecy. The former teaching (“old light") is then discarded, and the “new light," which is called a “refinement," supposedly brings the WTS to a fuller understanding of the prophecy or teaching in question.
In the case of the WTS, however, we do see current teachings contradicting earlier teachings and doctrines going back and forth between opposite interpretations. This is not maturation but mutation.