A central topic in ontology is the categories of being—fundamental classes that map out a comprehensive inventory of reality. Becoming, by contrast, covers change, like when an entity shifts from one state of being to another. Other suggested criteria identify reality with what is observable, measurable,a coherent,b useful, objective, intersubjective, or fundamental. It focuses on how things seem to be, distinguishing real appearances, which are as they seem, from illusory ones, which are not as they seem.
Anti-realism about abstract objects in mathematics takes various forms, including, but not limited to, fictionalism. Anti-realists hold that there are no abstract objects and offer alternative explanations. Realists and anti-realists about abstract objects debate whether, or in what sense, such entities form part of reality. Nominalism, another anti-realist view, rejects both mental and non-mental interpretations of universals. For example, a person may be a realist about universals and an anti-realist about values. In this sense, realism and anti-realism encompass many domain-specific positions across diverse fields.

Realism and anti-realism

Mereological universalism holds that any collection of entities constitutes a whole, even if the entities are otherwise unrelated. Various theories of the mereological principles underlying composition have been proposed. For example, David Lewis’s modal realism asserts that there exist countless spatiotemporally unified possible worlds, each just as real as the actual world. A different view suggests that reality is made up of many worlds that exist in parallel to one another, each representing a distinct way of how things could have been. In a narrow sense, being contrasts with becoming, and denotes stable or permanent aspects of reality. Some philosophers, such as Alexius Meinong, hold that being is a broader concept than reality, encompassing nonexistent objects, such as merely possible or incomplete objects, in addition to real or actual ones.
More general constraints arise from limits of human cognitive faculties rather than situation-specific circumstances, such as facts too complex for anyone to conceive. Testimony is a transmission of knowledge from one person to another through communication.k Memory is the capacity to store information from other sources and make it available to cognitive processes when needed. Reason is the ability to draw logical inferences and arrive at truths independent of immediate sensory input. Anti-realism is understood as a view that identifies the meaning of a statement with the evidence that would support it or the conditions under which a person is justified in asserting it. It opposes the idea that world and mind are essentially correlated, emphasizing the mind-independent nature of reality beyond the way humans perceive and think about it.

Realism and anti-realism

In psychoanalytic theory, the reality principle is a proposed mechanism that counteracts the pleasure principle, delaying immediate gratification when it collides with the demands of external reality. For example, value theory is concerned with the reality of values, and the philosophy of mathematics explores in what sense mathematical objects, like numbers and sets, form part of reality. Different worldviews offer distinct answers to existential questions about meaning, morality, and the nature of reality, such as the contrast between religious and secular worldviews. A worldview is a comprehensive framework for understanding reality and humanity’s place within it. One perspective holds that such objects are illusory or unreal because they lack existence in the physical world outside the simulation. The reality–virtuality continuum is a theoretical framework that posits a continuous scale of mixed reality forms.
Inspired by Leibniz, David Lewis (1941–2001) developed modal realism, maintaining that possible worlds are as real as the actual world. E. Moore (1873–1958) drew on common sense and empirical science to oppose idealism, emphasizing that the world exists independently of the mind. Responding to Kant’s philosophy, the German idealists sought a unifying principle as the foundation of all reality. In Hindu philosophy, the school of Advaita Vedanta emerged in the 8th century and held that the world of everyday appearances is an illusion, contrasting it with the ultimate reality of Brahman. Inspired by Plato’s realm of forms, Plotinus (c. 204 – c. 270 CE) identified the One as the supreme principle underlying all of reality. His student Aristotle (384–322 BCE) proposed a system of ten categories describing the fundamental constituents of reality.

Values

On this view, higher levels show greater complexity and new phenomena but depend on the lower ones and could not exist without them. Some philosophical approaches rely on the idea of fundamentality and dependence to analyze the world in terms of levels or layers, such as material, biological, psychological, and social reality. In the Hindu tradition, it is often identified with Brahman as the all-pervasive reality and the supreme principle grounding all being. Some outlooks suggest that only the fundamental level is ultimately real, arguing that non-fundamental entities are in some sense eliminable since reality can be described without them.

• Contemporary technology in the form of augmented and virtual reality can inform experience and raises questions about the ontological status of virtual objects.
• Inspired by Plato’s realm of forms, Plotinus (c. 204 – c. 270 CE) identified the One as the supreme principle underlying all of reality.
• Influenced by Kant, Edmund Husserl (1859–1938) argued that reality is tied to consciousness as an intersubjective correlate of experience that cannot be reduced to a wholly mind-independent substrate.
• It opposes the idea that world and mind are essentially correlated, emphasizing the mind-independent nature of reality beyond the way humans perceive and think about it.
• In the social sciences, critical realism holds that observable events in the social world only partially disclose reality.

Accordingly, worldviews address not only theoretical matters but also practical and evaluative outlooks about what matters and how one should act. Another view maintains that they are real as digital objects with genuine existence and causal powers, residing within and being constituted by computational processes. Similarly, virtual reality worlds may incorporate real-world objects into the simulation or be entirely virtual.l Although it is not a widely accepted position, various thought experiments undermining the reliability of human cognitive faculties are discussed in the academic literature. It denies the existence of knowledge in any form or domain, arguing that knowledge is impossible. These limitations indicate a gap whereby reality is not fully captured and exceeds knowledge.
Skepticism about metaphysics holds that it is not possible to know the fundamental nature of reality, such as claims about categories of being or the existence of universals. It holds that the scientific view of the world is either exactly or at least approximately true by presenting reality as it is. For example, emotivism holds that value statements express emotional attitudes of subjective approval or disapproval rather than objective facts. Anti-realist views reject the mind-independent existence of values and can take various forms. Realists hold that values are objective features of reality, meaning that there are mind-independent facts about whether something is good or bad, irrespective of subjective beliefs or personal preferences.
Monism and pluralism are families of views about the roles of unity and multiplicity in the structure of reality. According to this view, even a complete understanding of physics would not render sciences dedicated to higher levels, such as psychology, obsolete. Non-reductive physicalists hold that everything is ultimately physical while insisting that higher-level psychological facts cannot be reduced to fundamental physics. In this sense, there can be matter without biological life, whereas life is built upon matter and depends on it. Lower levels, by contrast, operate according to more basic mechanisms and are prior to the higher ones.
On this view, unobservable entities may be invoked in theory construction to aid prediction but should not be taken to exist. Scientific realism is the view that the best scientific theories provide an accurate description of a mind-independent world. Error theory asserts that all value statements are false because there are no values.i Another form of anti-realism maintains that value statements are neither true nor false but meaningless. According to subjectivism, values depend on the attitudes and preferences of individuals. Non-naturalism, another form of realism, maintains that values differ significantly from empirical properties and belong to another domain of reality.

• Lower levels, by contrast, operate according to more basic mechanisms and are prior to the higher ones.
• It focuses on how individuals experience reality and how conscious states are intentional or directed towards entities other than themselves.
• Another influential proposal treats mind-independence as a criterion of reality, arguing that real entities do not depend on how people think about them.
• Another structural feature concerns the idea that some entities depend on, or are grounded in, other entities.
• In China, beginning roughly in the 9th century, Neo-Confucianism maintained that reality has a rational order expressed in the principle Li, which acts as a ground of being.
• In Hindu philosophy, the school of Advaita Vedanta emerged in the 8th century and held that the world of everyday appearances is an illusion, contrasting it with the ultimate reality of Brahman.

Related concepts

In this sense, it is the state of being real or what all real entities have in common, separating them from unreal or illusory ones. In a slightly different sense, reality is not the totality itself but an aspect shared by all its constituents. Contemporary technology in the form of augmented and virtual reality can inform experience and raises questions about the ontological status of virtual objects. Other discussions examine space and time as frameworks that organize relations among entities, and laws of nature describing regularities or general patterns of how entities interact and changes unfold. Various criteria for distinguishing real from unreal entities have been proposed, including causal powers, mind-independence, and being non-illusory. It is often contrasted with appearance, opposing what is with what seems to be, although the accuracy and fundamentality of this contrast are disputed.

It characterizes realism as the view that the truth or meaning of sentences is determined by external standards or mind-independent reality. A semantic approach to the debate between realism and anti-realism, proposed by Michael Dummett, argues that the underlying disagreement concerns the meaning of statements rather than the existence of entities. On this view, reality is made up of countless concrete worlds existing in https://www.zumospin.net/ parallel without interacting with one another. In the social sciences, critical realism holds that observable events in the social world only partially disclose reality. Local realism is a view that combines the principle of locality with the notion that there are definite physical properties, whether or not they are being observed by someone.

Realism and anti-realism

It overlaps with the cognitive sciences, which investigate how cognitive processes transform information about the world, and with neuroscience, which studies the brain activities underlying such processes. It concerns the question of how mental and linguistic entities, such as thoughts and words, can establish contact with reality by successfully referring to things in the world. It focuses on how individuals experience reality and how conscious states are intentional or directed towards entities other than themselves. Epistemology, another philosophical subdiscipline, explores how people can know reality. They examine what it means for something to be real, how entities are divided into different categories of being, and which entities exist at the most fundamental level.