The general formal ontology (GFO) is an upper ontology integrating processes and objects. [1] GFO has been developed by Heinrich Herre, Barbara Heller and collaborators (research group Onto-Med) in Leipzig. Although GFO provides one taxonomic tree, different axiom systems may be chosen for its modules. In this sense, GFO provides a framework for building custom, domain-specific ontologies. GFO exhibits a three-layered meta-ontological architecture consisting of an abstract top level, an abstract core level, and a basic level. Primarily, the ontology GFO:
GFO (General Formal ontology) draws a fundamental distinction between concrete entities, categories and sets. Sets are described by an axiomatic fragment of set theory of Zermelo-Fraenkel, although fragments of anti-foundation axiom set theories such as ZF-AFA are considered.
Concrete entities are entities which are in time and space, while categories have universal character.
The common property of all categories is that they can be predicated of an entity.
Categories in GFO are further divided in immanent universals, conceptual structures and symbolic structures. Immanent universals are so-called Aristotlian universals, in the sense that they are considered in re. This means, that these universals exist in all the entities which instantiate an immanent universal, independent of an observer. An example of an immanent universal could be APPLE. The universal APPLE exists in all apples, independent of perception by an agent.
Conceptual structures are mental representations of entities or universals, and they exist in an agent's mind. For example, the individual representation of the (linguistic) term "apple" inside an agent's mind (determined by the agent's experience, knowledge and belief, etc.).
Symbolic structures are signs which may be instantiated by tokens. They have the property to stand for something beyond themselves. An example is the physical pattern "apple", which instantiates the "APPLE" symbolic structure.
GFO uses a theory of space and time which is inspired by the philosophy of Brentano. For time, time-intervals, called chronoids, are taken as primitive. Existentially dependent on these time-intervals are time-boundaries. Time-boundaries of different time-intervals may coincide. This notion of coincidence is equivalent to a formalization of time-based on the meets relation (due to Allen and Hayes).
Connected three-dimensional parts of space are called "topoids". As chronoids, topoids may coincide at a two-dimensional boundary. This boundary may coincide with other (two-dimensional) boundaries at a one-dimensional boundary, and so on.
GFO distinguishes processes and objects. Processes unfold in time, they have temporal parts. Objects (called presentials) have no temporal parts, and may only exist on time-boundaries. Presentials are dependent on processes. This can be seen as a derivation of the dependency-relations in the formalization of time: processes are always framed by a chronoid; and as time-boundaries are dependent on chronoids, so are presentials dependent on processes.
DOLCE and other ontologies face the problem of "identity": how is it possible to model the persistence of an object through time. In GFO, this problem is made explicit: all presentials explicitly exist only at a single time-boundary; persistence is modelled by a special type of category, a persistent.
Metaphysics is the branch of philosophy that studies the fundamental nature of reality, the first principles of being, identity and change, space and time, causality, necessity, and possibility. It includes questions about the nature of consciousness and the relationship between mind and matter, between substance and attribute, and between potentiality and actuality. The word "metaphysics" comes from two Greek words that, together, literally mean "after or behind or among [the study of] the natural". It has been suggested that the term might have been coined by a first century CE editor who assembled various small selections of Aristotle's works into the treatise we now know by the name Metaphysics.
In metaphysics, nominalism is the view that universals and abstract objects do not actually exist other than being merely names or labels. There are at least two main versions of nominalism. One version denies the existence of universals – things that can be instantiated or exemplified by many particular things. The other version specifically denies the existence of abstract objects – objects that do not exist in space and time.
In metaphysics, ontology is the philosophical study of being, as well as related concepts such as existence, becoming, and reality.
The problem of universals is an ancient question from metaphysics that has inspired a range of philosophical topics and disputes: Should the properties an object has in common with other objects, such as color and shape, be considered to exist beyond those objects? And if a property exists separately from objects, what is the nature of that existence?
Platonic realism is the philosophical position that universals or abstract objects exist objectively and outside of human minds. It is named after the Greek philosopher Plato who applied realism to such universals, which he considered ideal forms. This stance is ambiguously also called Platonic idealism but should not be confused with idealism as presented by philosophers such as George Berkeley: as Platonic abstractions are not spatial, temporal, or mental, they are not compatible with the later idealism's emphasis on mental existence. Plato's Forms include numbers and geometrical figures, making them a theory of mathematical realism; they also include the Form of the Good, making them in addition a theory of ethical realism.
Substance theory, or substance–attribute theory, is an ontological theory positing that objects are constituted each by a substance and properties borne by the substance but distinct from it. In this role, a substance can be referred to as a substratum or a thing-in-itself. Substances are particulars that are ontologically independent: they are able to exist all by themselves. Another defining feature often attributed to substances is their ability to undergo changes. Changes involve something existing before, during and after the change. They can be described in terms of a persisting substance gaining or losing properties. Attributes or properties, on the other hand, are entities that can be exemplified by substances. Properties characterize their bearers, they express what their bearer is like.
Reality is the sum or aggregate of all that is real or existent within a system, as opposed to that which is only imaginary. The term is also used to refer to the ontological status of things, indicating their existence. In physical terms, reality is the totality of a system, known and unknown. Philosophical questions about the nature of reality or existence or being are considered under the rubric of ontology, which is a major branch of metaphysics in the Western philosophical tradition. Ontological questions also feature in diverse branches of philosophy, including the philosophy of science, philosophy of religion, philosophy of mathematics, and philosophical logic. These include questions about whether only physical objects are real, whether reality is fundamentally immaterial, whether hypothetical unobservable entities posited by scientific theories exist, whether God exists, whether numbers and other abstract objects exist, and whether possible worlds exist.
In computer science and information science, an ontology encompasses a representation, formal naming, and definition of the categories, properties, and relations between the concepts, data, and entities that substantiate one, many, or all domains of discourse. More simply, an ontology is a way of showing the properties of a subject area and how they are related, by defining a set of concepts and categories that represent the subject.
Aristotle's Theory of Universals is Aristotle's classical solution to the Problem of Universals, sometimes known as the hylomorphic theory of immanent realism. Universals are the characteristics or qualities that ordinary objects or things have in common. They can be identified in the types, properties, or relations observed in the world. For example, imagine there is a bowl of red apples resting on a table. Each apple in that bowl will have many similar qualities, such as their red coloring or "redness". They will share some degree of the quality of "ripeness" depending on their age. They may also be at varying degrees of age, which will affect their color, but they will all share a universal "appleness". These qualities are the universals that the apples hold in common.
In logic, philosophy and related fields, mereology is the study of parts and the wholes they form. Whereas set theory is founded on the membership relation between a set and its elements, mereology emphasizes the meronomic relation between entities, which—from a set-theoretic perspective—is closer to the concept of inclusion between sets.
In logic and philosophy, a property is a characteristic of an object; a red object is said to have the property of redness. The property may be considered a form of object in its own right, able to possess other properties. A property, however, differs from individual objects in that it may be instantiated, and often in more than one object. It differs from the logical/mathematical concept of class by not having any concept of extensionality, and from the philosophical concept of class in that a property is considered to be distinct from the objects which possess it. Understanding how different individual entities can in some sense have some of the same properties is the basis of the problem of universals.
In metaphysics, the distinction between abstract and concrete refers to a divide between two types of entities. Many philosophers hold that this difference has fundamental metaphysical significance. Examples of concrete objects include plants, human beings and planets while things like numbers, sets and propositions are abstract objects. There is no general consensus as to what the characteristic marks of concreteness and abstractness are. Popular suggestions include defining the distinction in terms of the difference between (1) existence inside or outside space-time, (2) having causes and effects or not, (3) having contingent or necessary existence, (4) being particular or universal and (5) belonging to either the physical or the mental realm or to neither. Despite this diversity of views, there is broad agreement concerning most objects as to whether they are abstract or concrete. So under most interpretations, all these views would agree that, for example, plants are concrete objects while numbers are abstract objects.
Quantity or amount is a property that can exist as a multitude or magnitude, which illustrate discontinuity and continuity. Quantities can be compared in terms of "more", "less", or "equal", or by assigning a numerical value multiple of a unit of measurement. Mass, time, distance, heat, and angle are among the familiar examples of quantitative properties.
In philosophy, transcendence is the basic ground concept from the word's literal meaning, of climbing or going beyond, albeit with varying connotations in its different historical and cultural stages. It includes philosophies, systems, and approaches that describe the fundamental structures of being, not as an ontology, but as the framework of emergence and validation of knowledge of being. "Transcendental" is a word derived from the scholastic, designating the extra-categorical attributes of beings.
In information science, an upper ontology is an ontology which consists of very general terms that are common across all domains. An important function of an upper ontology is to support broad semantic interoperability among a large number of domain-specific ontologies by providing a common starting point for the formulation of definitions. Terms in the domain ontology are ranked under the terms in the upper ontology, e.g., the upper ontology classes are superclasses or supersets of all the classes in the domain ontologies.
In philosophy, the term formal ontology is used to refer to an ontology defined by axioms in a formal language with the goal to provide an unbiased view on reality, which can help the modeler of domain- or application-specific ontologies to avoid possibly erroneous ontological assumptions encountered in modeling large-scale ontologies.
Moderate realism is a position in the debate on the metaphysics of universals associated with the hylomorphic substance theory of Aristotle. There is no separate realm in which universals exist, nor do they really exist within particulars as universals, but rather universals really exist within particulars as particularised, and multiplied.
In philosophy, a process ontology refers to a universal model of the structure of the world as an ordered wholeness. Such ontologies are fundamental ontologies, in contrast to the so-called applied ontologies. Fundamental ontologies do not claim to be accessible to any empirical proof in itself, but to be a structural design pattern, out of which empirical phenomena can be explained and put together consistently. Throughout Western history, the dominating fundamental ontology is the so-called substance theory. However, fundamental process ontologies are becoming more important in recent times, because the progress in the discovery of the foundations of physics spurred the development of a basic concept able to integrate such boundary notions as "energy," "object", and those of the physical dimensions of space and time.
Compositional objects are wholes instantiated by collections of parts. If an ontology wishes to permit the inclusion of compositional objects it must define which collections of objects are to be considered parts composing a whole. Mereology, the study of relationships between parts and their wholes, provides specifications on how parts must relate to one another in order to compose a whole.