The theory of Forms is perhaps both the most often vilified, and the most commonly misunderstood, portion of Platonic philosophy. So let’s make a few preliminary gestures toward setting the record straight, and thereby getting a better understanding of why the Forms matter.
The Forms are frequently invoked in discussions of the common features shared by particular, enmattered things. Particular circles are alike in being round, individual horses are alike in their horsey character, etc. Yet this phenomenon of observed, apparent commonality is ambiguous. Is that commonality—that Form, that Idea—something that’s found within the particular individuals, something that emerges from them, or something that stands before or apart from them?
In his commentary on Aristotle’s Categories (pp. 82–83), Simplicius explains that “commonality” or “the common” (Greek: to koinon) can have three distinct senses:
- that which transcends the particulars, and is the cause of what is common within them;
- that which is common in particulars; and
- that which exists in our concepts, as the result of the cognitive process of abstraction.
The distinction made in this passage, incidentally, is the jumping-off point for the medieval “problem of universals,” where Simplicius’ three senses of commonality correspond, respectively, to what the medievals called ante rem (“before the thing”), in re (“in the thing”), and post rem (“after the thing”) universals.
What’s important for our purposes is that it’s only Simplicius’ third sense that refers to universals in the strict sense—that is, to the concepts that we in some sense generate or pull out from the particular things we encounter in the (material) world, and which we express with generic terms in ordinary language. Such abstractions are downstream from the commonality that is found in the particulars themselves. (By “upstream” and “downstream” throughout this discussion, I’m referring to what comes prior or posterior in the metaphysical processes of production and explanation.) This is one sense in which forms are sometimes talked about by Platonists—but only in an attenuated sense, of the forms that are in our souls.
On the other hand, we have the Forms in Simplicius’ first sense: the transcendent causal principles, which generate and explain the commonality found in particulars. The Forms in this sense, which belong not within the soul, but rather to the level of the intelligibles, are upstream of the commonality in particulars.
So to summarize: The transcendent, intelligible Forms (Simplicius’ #1) eternally pre-exist, and cause, the commonality of particulars (#2), from which in turn we humans generate concepts (#3) via the process of abstraction. When that abstractive process is done carefully and well, the concepts that it produces (#3) will correspond in useful and interesting ways to the transcendent Forms (#1), and will perhaps even assist us in making the leap from the awareness of concepts to the intuitive awareness of the intelligible Forms. Nonetheless, the transcendent Forms do not in any way depend upon our concepts; even if our concepts were never generated, or were constructed poorly, or were forgotten, this would in no way affect, diminish, or change the status of the transcendent Forms. This also entails that different and distinct cognitive faculities will be involved in our apprehension of concepts, and our apprehension of the transcendent Forms.
In my experience, most shallow criticisms of the theory of Forms neglect #1, and treat #3 as if it were the primary thing that the theory is about. Such critics then accuse the Platonist of putting the cart before the horse, as it were, since obviously such linguistic, conceptual abstractions arises from, and depend upon, the particulars and our encounter with those particulars. In other words, the critic says, it is a grave error to place #3 metaphysically upstream of #2, as if the abstractions (or the forms in soul) were somehow metaphysically explanatory of the commonality found in particulars.
The Platonist will agree that yes, this would be quite a serious mistake. But it’s not a mistake that the Platonist makes, since it has nothing to do with the actual theory of Forms. By distinguishing the transcendent Forms (#1) from the abstractions (#3), the Platonist is able to avoid this error, while also (by appealing to the agency of those transcendent Forms) being able to give an explanation for the commonality among particulars.
Any such explanation is in principle unavailable to the critic who ignores #1. So for the critic, that very commonality in things (#2) is necessarily inexplicable, and so the accuracy and utility of our concepts (#3) which follows from #2 is likewise inexplicable. The critic is left mired in nominalism, whereas the Platonist can account for the objectivity of our thought and talk.