John West wrote:

I'm inclined to say that red is a power to cause certain perceptions in normal perceivers under normal conditions (whether it's an irreducible power or reducible to certain microstructures is a separate issue).

I don't have a dog in the fight when it comes to color, my only point was that a universal can be instantiated in distinct particulars in virtue of distinct immanent structures.

John West wrote:

It helps to draw a distinction between universals and property-tropes. It's a truism that each universal is strictly identical—both qualitatively and numerically identical—in each of its instances; in contrast, property-tropes of the same type are only qualitatively identical. It looks like you're saying each red thing* has a property-trope of a certain type and that the tropes' respective universal provides the “intension” (to use overly linguisticist lingo) of that respective type.* Is that right?

I'm somewhat uncomfortable using the language of property-tropes, because I want to emphasize that the immanent structures in virtue of which universals are realized may be qualitatively diverse in some respects while nevertheless instantiating one and the same universal.  The example of Word provides an analogy: one and the same piece of software exists on your machine and mine (the universal).  Nevertheless, you have your copy and I have mine (the trope), but further the actual structure of magnetic states on my SSD in virtue of which Word is instantiated on my machine may be very different in some respects to the structure of magnetic states on your spinning disk in virtue of which Word is instantiated on your machine.  This immanent structure is what I referred to above as the λόγος within something.

I also want to head off a confusion before it arises: someone may think that I am simply referring to the matter in which the form becomes instantiated.  Instead, I am referring to the matter qua organized in a particular way in virtue of which a universal can become instantiated in this matter.  Incidentally, I believe Aristotle sometimes intends this when he says "form," and reading him in this way can sometimes clear up otherwise apparent contradictions in his logic  (e.g. in some of the more difficult passages of Metaphysics Ζ and Η).

John West wrote:

Standard question for the second horn of my dilemma: why not just say the tropes are perfectly similar or, if the above interpretation is right, stop at the universals? The Forms seem superfluous.

The Forms would be superfluous if the only explananda were property instantiation and qualitative identity among concrete particulars.  Aristotle is right that there is no need to posit "separate" (χωρίς) Forms if we simply want to explain why all red things have something in common.  But Plato develops his theory with larger problems in view.

In the first place, once we have identified what accounts for a, b, and c being red, we have not yet explained what it means to be red.  Here is one reason why I think Plato avoids talking about Forms of proper sensibles.  It is hard to see how redness has a meaning; we just see it.  What it means to be red is just that.  (In fact, I think he would maintain that we need a Form of Red, but it is very hard to get someone to see this dialectically.)  Consider, however, one of his standard examples: equality (he has quantitative equality in view, and for simplicity let's consider only equality of length).  We have equal sticks and we have the universal property of equality, but in addition we have what it means to be equal, a determinate intelligibility that we can grasp noetically.  We might imagine a universe emptied of all material objects yet populated with very intelligent minds.  Assuming that universals are ontologically dependent on the particulars that instantiate them, such a universe does not contain the universal equality, yet we can imagine the minds of this universe latching onto the intelligible standard of what it would take for X and Y to be the same length.

In the second place, Plato wants to explain why any of this intelligibility should appear to us in the material world in the first place.  Granting that we can explain why A, B, and C are all beautiful by referring to the universal beauty and even granting that we can understand the features of things in virtue of which this universal comes to be instantiated, we still have not answered the question: "Yes, but why is there beauty in the world and why should I be able to apprehend it?"  Plato takes it as central to the phenomenon of grasping "this is beautiful" that one refers one's present experience to an intelligible standard that does not depend on any particular things' being beautiful.  That things appear to us as beautiful is not self-explanatory.  In order for our experience to make sense we must have both (i) what it means to be beautiful, the intelligible standard to which perhaps nothing lives up, and (ii) a mind so constituted so as to recognize that this can be measured in light of that standard.

In the third place, the material particulars that participate in a Form are only analogues of that Form, whereas I do not think it makes sense to say that particulars are analogues of a universal.  This is important because this feature of the particular–Form relation helps to explain such things as (i) only partial and imperfect instantiations, (ii) the universal compresence of opposites in the material world, and (iii) the nature of coming to be and passing away relative to being.


 

John West wrote:

Yeah. If I recall, Gerson takes this further and says Plato doesn't posit Forms to account for the problem of universals at all.

Yes, this is another point on which I agree with Gerson's interpretation.  Lest people think that I agree with Gerson on all points, however, I once sat next to him at a banquet where he held forth for nearly an hour about how taxation was theft.  At the end of this, Sarah Broadie said something along the lines of, "Well Lloyd, I think you are crazy, but I hope we can still be friends as Platonists."

 

I hate to speak for someone else, but I got that impression.  Nearly all of what I have read from Gerson takes the form of "Here is why we should interpret Author A in manner X," rather than "Author A is right about X."  The subtext, however, is often "...and Plato's view (interpreted thus) is pretty awesome."

I had no idea Gerson was an Austrian. That is interesting. I far from an Austrian myself, though I find them much more interesting than their neoclassical cousins.