It was, perhaps, Socrates, and, later, more fully, Aristotle that first characterized the "thingness" of objects in our everyday reality as having form and matter. This hylomorphic theory can be seen as a first viable attempt to understand physical reality in terms of relationship and ontology. By pursuing a purely conceptual dichotomy, we can understand "matter" as an inchoate "stuff", or substance without form — this gets at the ontological aspect of "things", namely that they have "concrete" existence. (This view appeals in a very literal sense to a sculptor who fashions a work from malleable clay.) Following upon this insight, Thomas Aquinas realized that Aristotle's terminology applied equally to spiritual as well as to physical reality, and even achieved an interesting insight in the analysis of spiritual beings as having a nature (or substance) that is itself primarily relational. In Article 2 of Question 50, from the First Part, of the Summa Theologiae, Aquinas' Reply to Objection 3 is as follows:
Although there is no composition of matter and form in an angel, yet there is act and potentiality. And this can be made evident if we consider the nature of material things which contain a twofold composition. The first is that of form and matter, whereby the nature is constituted. Such a composite nature is not its own existence but existence is its act. Hence the nature itself is related to its own existence as potentiality to act. Therefore if there be no matter, and supposing that the form itself subsists without matter, there nevertheless still remains the relation of the form to its very existence, as of potentiality to act. And such a kind of composition is understood to be in the angels; and this is what some say, that an angel is composed of, "whereby he is," and "what is," or "existence," and "what is," as Boethius says. For "what is," is the form itself subsisting; and the existence itself is whereby the substance is; as the running is whereby the runner runs. But in God "existence" and "what is" are not different as was explained above1. Hence God alone is pure act.
Thus, Aquinas identified the non-corporeal nature of angels as, in essence, having form, but without matter, an insight he justified by saying that their effect upon material reality was, in an abstract sense, a realization of their "potentiality," and he equated the nature of angels as having a form in relationship to this potential (for example, the form defines — gives "shape" to — the potential in some respect), a form and a relationship that "subsists" (where "subsists" indicates either integral persistence in time, or, perhaps more generally, possessing ontological reality — being). In more modern terms, and borrowing from categories in science fiction, we might say that angels are "pure intellect" (and, of course, "will") in command of great energy.
This particular theory of the non-corporeal nature of angels is consistent with the theory that God's essence is his existence, in the sense that he is infinite and eternal potential and act. At this level, relationship and ontology become identified as one.
While this clearly gives us a language with which to discuss intelligible properties and relationships, it fails to consider a systemic perspective. This has numerous implications, for example, in not probing into the substructure of human beings, in particular, and material things, in general. Although Democritus had an insight into the atomic composition of matter, even he did not regard these building blocks as themselves having structure and potential, apart from rigid body motion. The experiments and insights that led to the discovery of the fundamental forces of nature, gravity, electromagnetism, the weak and strong nuclear forces, did not develop until modern times. The whole concept of force fields did not arise until the work of Michael Faraday in his investigation of electrostatic fields, even though examples of such classical fields (such as magnetic flux fields and gravity) were known, as physical phenomena (albeit, not appreciated as fields), to the ancients. Basic observable phenomena, such as adhesion, surface tension and viscosity, had no explanation (none, at any rate, that rose much above the level of animism). Aristotle, himself (and countless followers down the centuries), was notoriously wrong in such areas as the mathematics of gravitational attraction2. The motion of "animate objects" was "explained" through the artifice of the "anima" or "soul" (the defining hypothesis of animism), so that even animals must be considered to have souls. Indeed he regarded the soul as the "form" of the body - that which gave it shape as well as life, a perspective that leads to its own paradoxes3. Furthermore, although Aquinas was able to treat the moral content of human acts, he could not fully appreciate the paradox of free will in a causal universe. He could not appreciate how much human life is attributable to the systemic perspective we know today as "physiology," nor could he appreciate how much human intellect and awareness is attributable to the neurophysiology of the central nervous system.
In spite of the obvious drawbacks of the ancient and scholastic schools of thought, the vast majority of "practical theologians" such as priests and religious, did not learn sound approaches to theology that went much beyond the work of Aquinas until relatively recent times, centuries after newer perspectives were forced upon the scene by the advent of modern skepticism and the Protestant revolution in theology, both of which have become more, not less, thorny challenges to serious Catholics as they continued to develop, Galapagos-like in a kind of ecological isolation. Even today, there are huge pockets of pre-Newtonian thinking among practical theologians (and even among those who are considered "experts"), while there are countless others who are vulnerable to the siren song of absurdly fuzzy thinking with little more than a patina of modern scientific understanding. It was precisely this tendency that led Pope Leo XIII to issue his encyclical, "Aeterni Patris." 4. Notably, in that document, the Holy Father declared5,
For, as the enemies of the Catholic name, when about to attack religion, are in the habit of borrowing their weapons from the arguments of philosophers, so the defenders of sacred science draw many arguments from the store of philosophy which may serve to uphold revealed dogmas. Nor is the triumph of the Christian faith a small one in using human reason to repel powerfully and speedily the attacks of its adversaries by the hostile arms which human reason itself supplied. This species of religious strife St. Jerome, writing to Magnus, notices as having been adopted by the Apostle of the Gentiles himself; Paul, the leader of the Christian army and the invincible orator, battling for the cause of Christ, skillfully turns even a chance inscription into an argument for the faith; for he had learned from the true David to wrest the sword from the hands of the enemy and to cut off the head of the boastful Goliath with his own weapon.
In keeping with this thought, let us also observe that, although the hand of God can surely guide a mere pebble to its target, to leave theology defenseless against an enemy armed with the philosophical equivalent of weapons of mass destruction would be the height of folly sustained by the height of hubris. If we are to dispatch the giant with his own weapons (indeed, if we are to improve on them), we must first learn their use.
"The country which we went through and explored is a fine, rich land. If the LORD is pleased with us, he will bring us in and give us that land, a land flowing with milk and honey. But do not rebel against the LORD! You need not be afraid of the people of that land; they are but food for us! Their defense has left them, but the LORD is with us. Therefore, do not be afraid of them."