According to the Catholic Church, does the spiritual sense of scripture change with the times? A friend wrote this to me on Facebook, and had me a bit puzzled how to respond:

A law does not exist in order to be understood historically, but to be concretized in its legal validity by being interpreted. Similarly, the Gospel does not exist in order to be understood as a merely historical document, but to be taken in such a way that it exercises its saving effect. This implies that the text, whether law or Gospel, if it is to be understood properly—i.e., according to the claim it makes—must be understood at every moment, in every concrete situation, in a new and different way. Understanding here is always application.
—Hans-Georg Gadamer, Truth and Method, 307-308.

I don't know much about this particular German philosopher, but I've read enough Chesterton to be skeptical.  It seems to me that he's saying that the saving part, so at least the moral and anagogical (if not the allegorical) senses of scripture are fluid.
Is his theological axiom, which I summarize as:
Things that can be true and good according to an application of the spiritual truths revealed in the Gospel are true and good now, but, given that same application, weren't true or good in a different place or time consistent with Catholic teaching?
I am not a philosopher; nor am I familiar with Gadamer. Nonetheless, this excerpt from the Stanford Encyclopedia of Philosophy may help clarify Gadamer's meaning:

As Gadamer comments in Truth and Method, ‘application is neither a subsequent nor merely an occasional part of the phenomenon of understanding, but co-determines it as a whole from the beginning’ (Gadamer 1989b, 324). Theory and application do not occur, then, in separation from one another, but are part of a single hermeneutical ‘practice’.

Perhaps we could apply this teaching in an orthodox manner to Biblical interpretation by stating that the Bible must both illumine the intellect and guide our behavior in concrete situations. Nevertheless, to avoid a descent into subjectivity, we must bear in mind the teachings of the First Vatican Council.

For the doctrine of the faith which God has revealed is put forward not as some philosophical discovery capable of being perfected by human intelligence, but as a divine deposit committed to the spouse of Christ to be faithfully protected and infallibly promulgated. Hence, too, that meaning of the sacred dogmas is ever to be maintained which has once been declared by holy mother church, and there must never be any abandonment of this sense under the pretext or in the name of a more profound understanding.