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.
Inspired by Leibniz, David Lewis (1941–2001) developed modal realism, maintaining that possible worlds are as https://www.zumospin.net/ 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.
Related concepts
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.
As individual entities, they contrast with universals, which are general, repeatable entities that can have many instances, such as the color blue, the shape roundness, and the property of being a mammal. Various categories of being or constituents of reality are discussed in the academic discourse. Similarly, the many-worlds interpretation of quantum physics suggests that in quantum measurements, not only one but all possible outcomes occur, interpreted as a branching of the universe into multiple worlds. It is often contrasted with essence, which denotes the nature or characteristic features of an entity.
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.
Related concepts
For example, one view suggests that macroscopic objects, such as a chair, depend on the microscopic objects that underlie them, such as elementary particles. The structure of reality concerns the fundamental patterns of being, describing how entities are organized and interact with each other. According to a common view, concrete objects exist in space and time, such as a flower, a horse, and a ship. Events are proposed constituents of reality that occur in time, such as the discovery of penicillin and the Second World War.
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.
Realism and anti-realism
For example, psychologism asserts that mathematical objects are mental constructions or ideas rather than abstract objects. Fictionalists argue that discourse about abstract objects concerns fictional entities within make-believe frameworks. According to conceptualism, universals exist in the mind as concepts through which people categorize and order their impressions, acting as tools of cognitive organization rather than properties of external entities. Platonism about universals holds that they are part of reality in their own right, independent of the particular entities that instantiate them.
Realism and anti-realism
- Non-naturalism, another form of realism, maintains that values differ significantly from empirical properties and belong to another domain of reality.
- According to this view, what happened in the past fixes what will happen in the future, including human behavior.
- This view contrasts being real with being fake, like the distinction between a real duck and a fake one used as a decoy.
- 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 this sense, reality does not depend on human knowledge or consciousness and exists apart from them, including the aspects that no one is aware of.
- Responding to Kant’s philosophy, the German idealists sought a unifying principle as the foundation of all reality.
- Similarly, the many-worlds interpretation of quantum physics suggests that in quantum measurements, not only one but all possible outcomes occur, interpreted as a branching of the universe into multiple worlds.
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.
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.
Levels of reality
While some skeptical scenarios use the idea of a simulated reality to challenge the reliability of human cognition, contemporary technologies such as augmented reality and virtual reality can also inform experience. Moral skepticism is the view that there is no moral knowledge, for instance, that one cannot know whether a given behavior is morally right or wrong. Some forms target specific domains of knowledge, such as religious skepticism, which denies that beliefs about God or other religious doctrines amount to knowledge. Philosophers examine various limitations of knowledge or obstacles to the cognitive contact with reality. Philosophers discuss various sources of knowledge as ways of how this cognitive contact is established, including perception, introspection, reason, memory, and testimony.
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.
- For example, emotivism holds that value statements express emotional attitudes of subjective approval or disapproval rather than objective facts.
- Discussed in ancient Greek philosophy as the Eleatic principle, it states that to be real is to be able to produce changes and to be affected by them.
- Memory is the capacity to store information from other sources and make it available to cognitive processes when needed.
- Some doctrines hold that God constitutes the most fundamental level of reality as the divine origin of all creation.
- The widely accepted Big Bang theory holds that the universe began about 13.8 billion years ago, initially in an extremely hot, dense state, expanding and cooling ever since.
It holds that the debate is not based on a substantive disagreement but arises instead from conceptual confusions. For example, metaphysical idealism asserts that everything is essentially mental, for instance, by understanding material objects as ideas in the mind. In this sense, reality does not depend on human knowledge or consciousness and exists apart from them, including the aspects that no one is aware of. The widely accepted Big Bang theory holds that the universe began about 13.8 billion years ago, initially in an extremely hot, dense state, expanding and cooling ever since.