Ontology is the philosophical study of the nature being, of becoming, of existence, or reality, as well as the basic category of being in their relations. Ontology has been considered to be a part of, or even equivalent to, metaphysics, with the terms being used almost interchangeably.
History[]
Ontology is the examination of everything entailed in the word "being" or the word "thing". Some philosophers, including Platonists, argue that all nouns (including abstract nouns) refer to existent entities, while some others argue against this, arguing that geometry is a collection of intellectual activities, and is not itself an existent entity.
The fundamental questions in ontology would be such questions as, "What can be said to exist?", "What is a thing?", and "What are the meanings/modes of being?". A common approach involves dividing extant subjects and predicates into categories, with these categories differing widely. Aristotle's ten categories endured the test of time, but philosophers like Immanuel Kant came up with their own categories. Aristotle's categories deal with the essence of a thing, quality, quantity, relativity, and other major ontological issues. Ontology also questions what "being" or "existence" is, and this is of vital importance regarding a renowned argument used from the Middle Ages to prove God's existence. Others can question whether existence is divided into species, what entities (if any) are fundamental, if all entities are objects, if physical properties actually exist, what features are essential to given objects, how many levels of existence are there, what constitutes a level for that matter, what is a physical object, what does it mean to say that a physical/non-physical entity exists, when does an object go out of existence as opposed to merely changing, or if the subject-object split inevitable. Ontology relates to many other fields that might not have a direct connection.
Dichotomies[]
In ontology, there are a number of common dichotomies, seven of which are: universals (repeatable entities, common to many) and particulars; substance (oucia, with the first being an individual {such as a human}, and the second being possessive of substantiality, while only existing in a derivative sense {such as humanity}) and accidents (attributes of a certain substance {hair color, weight, etc.}, existing in another, and not in itself); abstract (has no physical reference) and concrete (has a physical reference); essence (confers quiddity {whatness}; contrasted with accident, which does not determine "whatness"; to ti esti {what it is}; opposed by nominalists) and existence; determinism (all events are determined by previous causes) and indeterminism (no event is certain, and the outcome of anything is probabilistic); monism (all existing things go back to a single source; only one thing is prior to everything else) and dualism (co-eternal binary opposition; everything is divided in two; body and spirit, matter and mind, good and evil, light and dark, etc.); and idealism (reality is fundamentally mental and immaterial, conscience determines material and is the origin of the world, all entities are composed of mind and spirit) and materialism (material determines conscience).
Divisions of being[]
All knowledge starts with the notion of being, the first and best-known of all ideas. To clarify the idea of being in the mind is to discover the primary conceptions into which it is divided, such as asking questions like "What is the object of thought?" Since being is the primary object of the intellect, one must find the first data. The aforementioned question has three answers from the standpoint of intelligibility: essence, substance, and actuality.
As the primary datum of the intellect, we give to it the name of "essence"; that is, to consider being from the standpoint of intelligibility. We use the term "essence" in the sense that essence is that in which any object of thought is immediately and primarily presented to the intellect. Every idea whatsoever, unless it be a logically impossible idea (such as a "square circle"), brings immediately before the mind something (an essence). The term nature can also be used as practically synonymous with essence, although essence and nature have, from a technical standpoint, distinct definitions. An essence can be understood as simply an object of thought as such, but every essence possesses its intelligible constitution.
Meaning of "being"[]
The meanings of "being"
The term "being" has two different meanings: being in existence (the act of being), and essence (being which is, or may be). In the Middle Ages, the Muslim philosopher Avicenna was the first to make the explicit distinction between essence and existence. The relationship between the terms presents us with the question, "Are essence and existence distinct in all things, except God?" In God, there is no difference between essence and existence.
Those essences with only a possible existence is data furnished immediately by our intellect and our ideas. The notion of essence, of being understood as "that which is or can be", is an extremely-wide concept applicable to any object of thought. The mere presentation in the mind of an object of thought is just the beginning of intellectual knowledge. We must consider objects of thought so far as they can be apprehended by the intellect. When the intellect judges, for example, such as affirming that Saint Peter is a man, among the various objects of though which can be realized to give him substance, each of the judgements is individual, concrete, and independent. What we know of Peter is first that we know that he is a man; it is such objects of thought such as humanity that we perceive in Peter, just as we may perceive redness in perceiving a rose. It is what a thing is that our mind apprehends.
Essence[]
Types of essence
We can subdivide essence between its widest sense and its strict sense; between what (whatness) and that which (haeccity). "What" is essence in the wide sense; "that which" is essence in the strict sense; "essence" is what a thing is necessarily and primarily as the first principle of its intelligibility; "existence" is a thing's act of being (the fact of actually existing, outside nonentity and outside causes); and "suppositum" is the primary subject of existence and action ("that which is" in the strictest sense of the indivudal nature of the thing; incommunicable to any other object).
In the notion of "what is", there are further distinctions that be made to determine what is absolutely the primary datum of the intellect from the standpoint of intelligibility. Peter is a man before he is capable of laughter of seating himself, so the being in which the intellect is in the first place directed, is its essence; in Peter's case, his humanity is his essence. His capacities for other activities are secondary, and not of his essence, although his essence, in turn, considered in terms of being his nature, can determine such capacities as thinking, or talking, or walking, etc. From the standpoint of intelligibility, Peter is a man before being mortal, and also an animal before being mortal, distinguishing between genus and species.
If we know that an object is a man without knowing what a man is, we are confused, making its intelligibility imperfect. If we are able to define the object, we possess a distinct knowledge of the being in question, with the intellect apprehending the first principle of intelligibility perfectly.
Essence in the wide sense is the essence of something, that is, in the strict sense, apprehended more or less completely in some or other of its properties. Supposition is the primary subject of existence and action, such as the "that which is" in the strict sense of individual nature (circumscribed) of the thing, incommunicable to any other object.
Individuals possessing the same essence are on the same level, in respect of the primary intelligible being, being essentially equal. Nevertheless, they differ from each other. Such characteristics peculiar to an individual are not derived from the essence, otherwise they would be identical. What distinguishes them as individuals are non-essential characteristics.
A chart describing the concept of being
The individual nature is not the first principle of intelligibility, as it is a principle of individual matters; the very constitution of the individual nature's principle is individual. Essence, quiddity, and nature all denote a universal, but when we consider the essence as individuated by matter or as possessing a singular mode of existence, it comes to the individual nature.
Individuality of substance[]
The intellect apprehends substance as individual. Those things that can really exist are, by nature, circumscribed in their being as a self-contained unit - an individual. It is for this reason that Aristotle made the distinction between primary and secondary substances. Universals do not have a separate existence of their own, existing only in individual things; the substantiality in that sense would be secondary and not primary. Our intellect has no direct knowledge of substance in its individuality, instead turning to the images from which it derives its ideas. In relation to existence, the intellect recognizes a being as an individual substance.
A thing is said to exist "in itself" (in se) when it self-constitutes the whole which exists. Existence per se (by itself) and in se (in itself) can be described as a substance in general (per se) or something itself containing everything necessary to exist (in se). That which is a se (existing from itself) is also per se, but not necessarily the other way around; it possesses in itself the explanation of its entire existence, therefore being uncaused. Created substances are caused, lacking "aseity". That which exists from itself (a se) cannot cease to exist, but that which exists by itself (per se) can lose its existence.
Change/Motion[]
Chart describing being
An observation made 2,500 years ago by Heraclitus was: things change. Like all primary notions, it is difficult to scientifically explain change or motion. For transition to exist, there must be something which is the subject of change. There is no change without a subject, which must have been in existence before change occurred; being is prior to change.
The starting point of motion/change is that the being which is the product of change is something that would have the aptitude for change; it must be capable of "becoming". In that sense, it is not a pure "nothing", with Parmenides saying "from nothing comes nothing". Jacques Maritain used Aristotle's example of an arrow: an arrow is originally on a bow (and nowhere else), but it could be on a target, possessing the means for being there. That which changes is said to be in potency or potentiality; the transition/motion actualizes that potentiality, becoming an actuality. Being, considered in relation the fullness and perfection which the term signifies, is divided into being in the strict sense (act; actuality) and the power of being (potency; potentiality). The product of change arises neither of being out of actuality nor out of nothing.
All changeable (mutable) things are compounded of potentiality and actuality. God alone, since he is absolutely immovable/immutable, is absolutely changeless, and is devoid of any potentiality. Potentiality and actuality divide between them the totality of created being in both substance and accidence, being transcendental of any class or category. The substance of bodies is compounded with potentiality (first matter) and act (substantial form), while incorporeal things are not composite. Every accident is an accidental form. The intellect is an accidental form whose subject is the soul, and it is in potentiality, with respect to a particular act of thought; hence the distinction between passive and active intellects. Concluding axioms would be:
- Potentiality cannot exist in the pure state apart from any act.
- Nothing is induced that is drawn from potentiality to act without a cause; whatever is moved is moved by another.
- Actuality is prior to potentiality.
- Potentiality is essentially relative to act, and is the sake of the act/actuality.
- Act and potentiality belong to the same order (substance or accident).
- Everything acts according to its nature in act
- The combination of two beings in actuality cannot produce something which is one of itself.
Actuality and Potentiality[]
Historically, philosophers studying actuality and potentiality have divided into three schools. The positions are: that of Aristotle and Thomas Aquinas (God is all actuality); the exaggerated intellectualism of Parmenides, Baruch Spinoza, and Georg Wilhelm Friedrich Hegel (refusing to admit the notion of potentiality; motion is unreal; and creatures must contain the same nature as God - pantheism); and that of anti-intellectualism of Heraclitus and Henri Bergson (pure actuality can no longer exist). From natural philosophy, hylomorphic theory tells us that every corporeal substance is compounded of first/prime matter (pure potentiality) and substantial form (prime actuality).