The Metaphysical Ladder of Ascent to God - A First Look at Aquinas' Essay "De Ente et Essentia"

On Being and Essence

De Ente et Essentia is one of Aquinas' most difficult works, yet in this short essay, there are bundles of formulations which make it very pithy. Below is a look at some of the themes from the essay from a first reading that I did. I hope to return to this essay again and augment this post and expand on these insights further. 
You may also access the PDF of the reading below for your own use. 

Man's Knowledge Versus Being
As Aristotle mentioned at the beginning of the Physics, and Aquinas talks about in this essay, man's mode of knowing compared to the different modes of being do not correlate directly, but rather in an inverse way. That which is most real and unified in itself, formal being, is that which we as humans come to know last. The fact is that as embodied spirits in matter, all knowledge begins for us from the individuated, the divided, and the spread-out in matter. As we grow and develop our intellectual powers, we begin to move from the sensible and material particulars to unifying reality with our higher faculties, approximating reality more as it is in-itself and not just as it appears to us. Thus, we come to know that which is most real and united, but only in an indirect and mediated way through our mental conceptualizations of it. Thus, here we are discussing the ways in which we are able to transcend the principle of division into the principle of being and unity as human beings. We are discussing form, matter, essence, genus, species, and composite. Let’s make some sense out of these concepts. 

Sensible and Material 
All knowledge begins through the senses, which take its data via individualized and purely material modes. This feeling, this smell, this touch, that sight of colors and order. We can then begin to associate these sets of data with each other to form patterns by which to navigate the material world. Now, humans can actually go beyond this and take these material patterns and extract from them “concepts”. This is where we can strip the individual and unique away from the pattern and keep the pattern as something which can apply to many, i.e. a universal notion of the pattern. Thus we can conceive of “man” or “dog,” for example. 

First and Second Order Abstractions 
Those concepts would be known as first order intentions because they are primary or first in the order of human knowledge. They refer to patterns of real entities that we perceived in the world. But remaining at the first order concepts is still somewhat divided in terms of our knowledge. Humans are able to unify their knowledge on a deeper level and unite reality even beyond the differences that remain on the first order conceptions. What’s common between man and dog, I wonder? We can abstract from our abstractions. This means we can then leave the realm of the observable and enter into a realm of deeper unities that can’t be observed, but which are more real in a sense. We can then create groupings of patterns that are not ever witnessed in nature. We can move more and more upward, so to speak, regarding unity with being until we reach a being in which there is no distinction between any type of being and division or pattern, they are one and the same. Through the mind we are able to leave earth and ascend to God through contemplation. This is probably why Aristotle said it was the highest human function. 

Genus, Species, and Composite 
Let’s go back though and get more specific about this process of ascent. The lowest level is a sensible experience of a composite thing, this man, Socrates, with his snub nose and bald head. Here the form and this specific matter are united into the individual. Then we can abstract the form from the individual and create an idea of “Socrates,” which cannot be defined directly, but indirectly through the use of other universal descriptions. But we can then abstract further and create the idea of “man,” either in a determinate sense or indeterminate sense. A man in a determinate sense is like Socrates with these specific attributes. In an indeterminate sense, it is just animality plus rationality, essentially, and accidentally, potentially many, many options regarding things like color, hair, etc… Now we have moved beyond the first order concept to a second order concept of species or essence, that of “humanity.” These never exist completely in an individual for, as was mentioned, have many accidental characteristics from many individuals, but in an essential way do exist in every individual because you wouldn’t be human otherwise. For living things this is so because you have to have certain essential features to live, otherwise you’d cease to be that thing. 

Now, we can abstract farther into the second order by creating something called a genus. A genus is then a higher level or more encompassing pattern that we see in nature. For example, animality, yet never exists of itself. There are no “animalities” running around, only being which embody the general characteristics of animality in a specific way. This is to take away the specific difference or form at one level of analysis and revert back to a simpler or more fundamental specific difference or form at a more basic level of analysis.

The Metaphysical Ascent to Angels and God 
Here you can now see how humans, through their rational power, unite the formal aspect of being which is spread out and individuated because of matter. And then taking it further and creating unities that are more and more encompassing by which to describe the world. At a certain point one reaches these mental unities which then no longer include matter anymore. You can reach a point in which to consider intellect and will alone, two non material facilities as groupings or a genus, though each member of those genus is its own species which actually exists as such because there’s no individuating matter. Then finally we are lead to the end of this process by which all being is unified and there is nothing which designates parts by which to form patterns from, there is just complete unity and being. In other words, essence and existence are the same. What the thing is, is exactly how it exists. This is when we reach God who exists perfectly as he is as a unity without parts and encompassing all being. Thus you cannot our God in any genus or species. There is no pattern by which to classify him, except only analogously. One can only just experience him directly and that’s it. Even then it’s something ineffable because word rely on conceptual patterns of which there’s not one for God. 
Maybe the argument that one could make is that being is a pattern by which to classify God, but even then “being” doesn’t exist as such as something separate. You can’t get out of it to conceive of it, rather being is defined in and by God as its source and fullness. 
1 - Aquinas, Thomas. De Ente et Essentia