What spren are?

[Ripheus23]

[I think this is worth standing as a Cosmere-level thread due to the descriptions of Nightblood as a "robot spren" and Adonalsium as "something Rosharans would think was a spren."]

So, philosophers believe all kinds of weird things about all kinds of weird things. One question is, are there Platonic Forms, or only individual objects, or anything in-between or around those two or what? One answer that some philosophers have offered to that "or what" is as follows (from the Stanford Encyclopedia of Philosophy article on tropes):

Quote

Trope theory [not to be confused with a theory of narrative tropes] is the view that reality is (wholly or partly) made up from tropes. Tropes are things like the particular shape, weight, and texture of an individual object. Because tropes are particular, for two objects to ‘share’ a property (for them both to exemplify, say, a particular shade of green) is for each to contain (instantiate, exemplify) a greenness-trope, where those greenness-tropes, although numerically distinct, nevertheless exactly resemble each other.

Apart from this very thin core assumption—that there are tropes—different trope theories need not have very much in common. Most trope theorists (but not all) believe that—fundamentally—there is nothing but tropes. Most trope theorists (but, again, not all) hold that resemblance between concrete particulars is to be explained in terms of resemblance between their respective tropes. And most (but not all) hold that resemblance between tropes is determined by their primitive intrinsic nature.

Spren are, I think, sentient tropes. They are not perfect Forms, but they are not like normal particular objects, either, and they are quasi-repeatable. They seem, in fact, to be tropes that can only be instantiated in normal objects (be physically truly predicated of such objects) by choice, at least if the Nahel bond is more than just a raw association between a physical agent and a spren. If Adonalsium was their original source, I think he must have done something to the level of reality on which the difference between universals, objects, and tropes has its own place,* in order to separate a great number of pure tropes from the mass of possibility, yet unassigned to specific objects. (Messing with the logical order of predication in physical reality itself does strike me as a divine kind of thing to do...)

*We can map this onto the three Realms, then: universals are of the Spiritual Realm, objects are of the Physical Realm, and tropes/spren are of the Cognitive Realm, as such.