Like there are only relations and no relata, or that all fundamental things-in-themselves stand in relation to other fundamental things?
I suspect I'm missing what you mean by "relational"...
Hmm, it's kind of just a "proto-thought" of mine, I think.
While I like Kant and there being a difference between phenomena and Noumena, but still, each only "exists" in the sense that they are not the other. So, something is only a something in so far as it is not other things, so by difference, but at the same time, it needs to all be a part of a whole thing (for example the Universe
in toto). Again, this is a real "raw" thought here.
So, in the manner of the quote, is there mind absent matter? No, it's something derived from matter. Is there matter absent space/time? No, matter is ensconed in and influences/is influenced by space/time. And while space/time is a noumena to some degree, that is, it seems to have existed before we knew it did/actually did, but at the same time, as something experiential, it could only be relational to a thing to experience it.
So, I guess, as an example, if there is only a proton in the universe, is there space or time? Even if it was "moving" what is it moving toward or away from? What is it's speed then and how could it have one? What then would space or time mean?
Again, I don't think I'm really prepared for a "full implications" of this though, but a thought I had none-the-less.