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.
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.
This view emphasizes that reality is encountered, rather than invented, and can resist or frustrate beliefs and desires, unlike malleable imaginary creations. Another influential proposal treats mind-independence as a criterion of reality, arguing that real entities do not depend on how people think about them. The Eleatic principle is controversial because it is typically taken to deny that abstract objects studied in fields like mathematics, such as numbers, are real. However, stories about Santa Claus, such as written texts in children’s books, are part of reality since they can influence how people think. 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. Criteria of reality are proposed features or standards that distinguish real entities from unreal ones.

Levels of reality

It comprises beliefs, ideas, and attitudes that form a background against which people interpret experiences, make decisions, and navigate life. By contrast, Arthur Schopenhauer (1788–1860) criticized German idealism and held that a blind, irrational will is the underlying principle of reality. Immanuel Kant (1724–1804) rejected the possibility of objective knowledge of the things in themselves, arguing instead that all experience is shaped by the innate structures of human cognition. Plato (c. 427 – c. 347 BCE) argued for the existence of a realm of eternal forms or ideas in addition to the material world of mutable entities.
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.
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.

Levels of reality

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.
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.

Values

• In ancient Greek philosophy starting in the 6th century BCE, the pre-Socratics discussed the first principles from which all things arise.
• 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.
• Various historiographical debates address the question of whether a truly objective account of the past is possible.
• Inspired by Leibniz, David Lewis (1941–2001) developed modal realism, maintaining that possible worlds are as real as the actual world.
• In the broadest sense, being is the most general category that applies to everything and contrasts only with nothingness.
• Tomi Lahren has blasted West Wilson over his views on transgender athletes.

Naturalism argues that values are part of the natural world and can be studied by the natural sciences through empirical observation. Some positions concern the existence of values in general, while others are limited to specific domains, such as moral, aesthetic, or religious values. Formalism, another form of anti-realism, understands mathematics as a practice of symbol manipulation, suggesting that mathematical truth is grounded in whether the manipulation rules permit the construction of a proof. According to conventionalism, the truth of mathematical statements rests on linguistic conventions or definitions, rather than on their relation to language-independent reality.

• Testimony is a transmission of knowledge from one person to another through communication.k
• Formalism, another form of anti-realism, understands mathematics as a practice of symbol manipulation, suggesting that mathematical truth is grounded in whether the manipulation rules permit the construction of a proof.
• It comprises beliefs, ideas, and attitudes that form a background against which people interpret experiences, make decisions, and navigate life.
• Scientific realism is the view that the best scientific theories provide an accurate description of a mind-independent world.
• In a slightly different sense, reality is not the totality itself but an aspect shared by all its constituents.

Anti-realism rejects this view, arguing instead that there is no external world or that reality depends in certain respects on mental processes, subjective perspectives, or social conventions. Realism and anti-realism are families of views concerning the mind-independence of reality. Some interpretations of quantum mechanics hold that measurement outcomes are inherently probabilistic, thereby rejecting causal determinism, but this is not true for all interpretations.g According to this view, what happened in the past fixes what will happen in the future, including human behavior. Causal determinism is the view that every event is fully determined or necessitated by prior events. Laws of nature play a central role in the physical sciences by providing frameworks for predicting outcomes under specified conditions.

Related concepts

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.

Levels of reality

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 https://www.zumospin.net/ 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.

For example, the laws of thermodynamics describe how heat and other forms of energy behave, such as the idea that the total amount of energy is always conserved. Existence monism contrasts with existence pluralism, which aligns more closely with everyday experience by asserting that reality is made up of many objects. There are different ways to conceptualize the relation between fundamental and non-fundamental entities, including the ideas of ontological dependence, metaphysical grounding, reduction, supervenience, and emergence. Another structural feature concerns the idea that some entities depend on, or are grounded in, other entities.