First of all, thank you for the superb response. It was just what I was looking for. I’m trying to ‘join the dots’ in respect to some deep questions in epistemology and (especially) the history of ideas in which my reading is still patchy, but about which I hope I have some insights. Your account really helps me understand where I should look to join more of them.
Compare with my comment in another thread
Why? Because a representation is after all another kind of thing. And then you have the problem of how one thing (the representation) relates to the actual thing. Whereas in reality, a numeral is really the symbol for an intellectual act.
I think it’s this ‘active’ nature of the understanding which eludes so much of the modern discussion.
This is also something I’ve noticed in the commentaries. I suppose the lineage is Brentano’s study of Aristotle and his subsequent influence on Husserl. ‘Intentionality’ in Brentano’s and Husserl’s sense is also active and participatory. Husserl’s phenomenology speaks of grasping eidetic structures through a kind of intellectual (noetic) insight. (I have Sokolowsii, often discussed by @Count_Timothy_von_Icarus but I haven’t made headway with it. Likewise with Mind and World.)
One thing I wonder about here is what exactly is meant by “causal” in the naturalistic account. In the Churchlands’ framework the explanation seems to be entirely in terms of neural processes — pattern recognition, statistical learning, network dynamics, etc. But that’s basically an account in terms of material and efficient causes.
The Thomistic picture is operating with a broader notion of causation. When the intellect grasps a universal, it isn’t just another efficient process happening in the brain; it’s the apprehension of a form — what Aristotle and Aquinas would call a formal cause.
So a neuroscientific account might describe the physiological conditions under which abstraction occurs, but it doesn’t obviously explain the intelligibility that is grasped. If everything is reduced to material and efficient causation, it seems to risk turning understanding itself into just another physical process — which rather undercuts the sovereignty of reason that the account is supposed to explain.
This also seems related to the “argument from reason” in contemporary philosophy, which raises a similar worry: if our beliefs are explained entirely in terms of non-rational physical causes, it becomes hard to see how the truth of those beliefs plays any role in producing them. It can’t really answer the question of ‘why do you think that?’ other than by saying ‘my neurons made me do it!’
Right. This is right at the centre of my overall thesis, such as it is - the loss of the sense of relatedness to being. Everything translated into relations between scientific abstractions from which the felt reality of existence has been bracketed out. That is more than just a philosophical argument, it’s a different state of existence or way of being.
Again, great response. Many of the sources you mention are on my list, with the difference being that you’ve actually read them. 
Good question. My sense is that phenomenology and embodied cognition don’t necessarily eliminate the distinction, but they probably reframe how we understand the transition from sensory experience to intellectual grasp.
The Thomistic claim isn’t that the intellect operates independently of the senses — Aquinas actually insists that nothing is in the intellect that was not first in the senses. So intellectual understanding still depends on sensory presentation (the phantasm). What the intellect adds, on the classical view, is the ability to grasp the intelligible pattern or essence that is not itself given as a particular sensory feature (a.k.a. insight.)
Embodied cognition might then be seen as giving a richer account of how the sensory and imaginative side of that process works — how patterns emerge through interaction with the world — while the Thomistic claim would be that understanding those patterns as universal still requires an intellectual act. From Aristotle, it is the ‘faculty of reason’, the very faculty that differentiates humans from other animals (and for that reason, is inimical to naturalism, which tends to see us on a continuum.)
One of the things enactivism seems to recover is the sense of an idea not as a static representation stored in the mind, but as an active grasp or articulation of intelligibility in experience. In that respect it feels closer to the older Aristotelian–Thomistic picture than to the representational models that dominated modern philosophy. Husserl still preserves that in his ‘ideal objects’.
Ideal Objects
In Edmund Husserl’s phenomenology, ideal objects (or irreal objects) are non-spatiotemporal, immutable entities—such as numbers, logical laws, or meanings (species)—that exist independently of individual acts of consciousness but are grasped through eidetic intuition. They are distinct from real, physical objects (e.g., this specific cup) because they are universal and can be instantiated in multiple places simultaneously, like the concept of “redness”. The similarities with Platonic realism are fairly obvious although there are also differences.
One thing that strikes me in these discussions is how naturally the phrase “active intellect”, associated with Aristotle, also brings Kant to mind. Both reject the idea that the mind simply receives sensory data passively. But the key difference seems to be that for Aquinas the intellect actualizes intelligibility already present in particulars, whereas for Kant intelligibility arises from the structuring activity of the understanding itself.
I’m curious how others here see that contrast in relation to the Thomistic account of universals.