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Phenomenalism is the view that physical objects cannot justifiably be said to exist in themselves, but only as perceptual phenomena or sensory stimuli (e.g. redness, hardness, softness, sweetness, etc.) situated in time and in space. In particular, some forms of phenomenalism reduce talk about physical objects in the external world to talk about bundles of sense-data.



Phenomenalism is a radical form of empiricism. Its roots as an ontological view of the nature of existence can be traced back to George Berkeley and his subjective idealism, upon which David Hume further elaborated. [1] John Stuart Mill had a theory of perception which is commonly referred to as classical phenomenalism. This differs from Berkeley's idealism in its account of how objects continue to exist when no one is perceiving them (this view is also known as "local realism"). Berkeley claimed that an omniscient God perceived all objects and that this was what kept them in existence, whereas Mill claimed that permanent possibilities of experience were sufficient for an object's existence. These permanent possibilities could be analysed into counterfactual conditionals, such as "if I were to have y-type sensations, then I would also have x-type sensations".

Empiricism theory that states that knowledge comes only or primarily from sensory experience

In philosophy, empiricism is a theory that states that knowledge comes only or primarily from sensory experience. It is one of several views of epistemology, the study of human knowledge, along with rationalism and skepticism. Empiricism emphasises the role of empirical evidence in the formation of ideas, rather than innate ideas or traditions. However, empiricists may argue that traditions arise due to relations of previous sense experiences.

Ontology study of the nature of being, becoming, existence or reality, as well as the basic categories of being and their relations

Ontology is the philosophical study of being. More broadly, it studies concepts that directly relate to being, in particular becoming, existence, reality, as well as the basic categories of being and their relations. Traditionally listed as a part of the major branch of philosophy known as metaphysics, ontology often deals with questions concerning what entities exist or may be said to exist and how such entities may be grouped, related within a hierarchy, and subdivided according to similarities and differences.

George Berkeley Anglo-Irish philosopher

George Berkeley – known as Bishop Berkeley – was an Irish philosopher whose primary achievement was the advancement of a theory he called "immaterialism". This theory denies the existence of material substance and instead contends that familiar objects like tables and chairs are only ideas in the minds of perceivers and, as a result, cannot exist without being perceived. Berkeley is also known for his critique of abstraction, an important premise in his argument for immaterialism.

As an epistemological theory about the possibility of knowledge of objects in the external world, however, it is probable that the most easily understandable formulation of phenomenalism is to be found in the transcendental aesthetics of Immanuel Kant. According to Kant, space and time, which are the a priori forms and preconditions of all sensory experience, "refer to objects only to the extent that these are considered as phenomena, but do not represent the things in themselves". While Kant insisted that knowledge is limited to phenomena, he never denied or excluded the existence of objects which were not knowable by way of experience, the things-in-themselves or noumena, though he never proved them.

Epistemology A branch of philosophy concerned with the nature and scope of knowledge

Epistemology is the branch of philosophy concerned with the theory of knowledge.

Immanuel Kant Prussian philosopher

Immanuel Kant was an influential German philosopher. In his doctrine of transcendental idealism, he argued that space, time and causation are mere sensibilities; "things-in-themselves" exist, but their nature is unknowable. In his view, the mind shapes and structures experience, with all human experience sharing certain structural features. He drew a parallel to the Copernican revolution in his proposition that worldly objects can be intuited a priori ('beforehand'), and that intuition is therefore independent from objective reality. Kant believed that reason is the source of morality, and that aesthetics arise from a faculty of disinterested judgment. Kant's views continue to have a major influence on contemporary philosophy, especially the fields of epistemology, ethics, political theory, and post-modern aesthetics.

In metaphysics, the noumenon is a posited object or event that exists independently of human sense and/or perception. The term noumenon is generally used when contrasted with, or in relation to, the term phenomenon, which refers to anything that can be apprehended by or is an object of the senses. Modern philosophy has generally been skeptical of the possibility of knowledge independent of the senses, and Immanuel Kant gave this point of view its canonical expression: that the noumenal world may exist, but it is completely unknowable through human sensation. In Kantian philosophy, the unknowable noumenon is often linked to the unknowable "thing-in-itself", although how to characterize the nature of the relationship is a question yet open to some controversy.

Kant's "epistemological phenomenalism", as it has been called, is therefore quite distinct from Berkeley's earlier ontological version. In Berkeley's view, the so-called "things-in-themselves" do not exist except as subjectively perceived bundles of sensations which are guaranteed consistency and permanence because they are constantly perceived by the mind of God. Hence, while Berkeley holds that objects are merely bundles of sensations (see bundle theory), Kant holds (unlike other bundle theorists) that objects do not cease to exist when they are no longer perceived by some merely human subject or mind.

God Divine entity, supreme being and principal object of faith

In monotheistic thought, God is conceived of as the supreme being, creator deity, and principal object of faith. The conceptions of God, as described by theologians, commonly include the attributes of omniscience (all-knowing), omnipotence (all-powerful), omnipresence (all-present), and as having an eternal and necessary existence. Depending on one's kind of theism, these attributes are used either in way of analogy, or in a literal sense as distinct properties. God is most often held to be incorporeal (immaterial). Incorporeality and corporeality of God are related to conceptions of transcendence and immanence of God, with positions of synthesis such as the "immanent transcendence". Psychoanalyst Carl Jung equated religious ideas of God with transcendental aspects of consciousness in his interpretation.

Bundle theory, originated by the 18th century Scottish philosopher David Hume, is the ontological theory about objecthood in which an object consists only of a collection (bundle) of properties, relations or tropes.

In the late 19th century, an even more extreme form of phenomenalism was formulated by Ernst Mach, later developed and refined by Russell, Ayer and the logical positivists. Mach rejected the existence of God and also denied that phenomena were data experienced by the mind or consciousness of subjects. Instead, Mach held sensory phenomena to be "pure data" whose existence was to be considered anterior to any arbitrary distinction between mental and physical categories of phenomena. In this way, it was Mach who formulated the key thesis of phenomenalism, which separates it from bundle theories of objects: objects are logical constructions out of sense-data or ideas; whereas according to bundle theories, objects are made up of sets, or bundles, of actual ideas or perceptions.

Ernst Mach Austrian physicist and university educator

Ernst Waldfried Josef Wenzel Mach was an Austrian physicist and philosopher, noted for his contributions to physics such as study of shock waves. The ratio of one's speed to that of sound is named the Mach number in his honor. As a philosopher of science, he was a major influence on logical positivism and American pragmatism. Through his criticism of Newton's theories of space and time, he foreshadowed Einstein's theory of relativity.

That is, according to bundle theory, to say that the pear before me exists is simply to say that certain properties (greenness, hardness, etc.) are being perceived at this moment. When these characteristics are no longer perceived or experienced by anyone, then the object (pear, in this case) no longer exists. Phenomenalism as formulated by Mach, in contrast, is the view that objects are logical constructions out of perceptual properties. On this view, to say there is a table in the other room when there is no one in that room to perceive it, is to say that if there were someone in that room, then that person would perceive the table. It is not the actual perception that counts, but the conditional possibility of perceiving.

Logical positivism, a movement begun as a small circle which grew around the philosopher Moritz Schlick in Vienna, inspired many philosophers in the English speaking world from the 1930s through the 1950s. Important influences on their brand of empiricism included Ernst Mach — himself holding the Chair of Inductive Sciences at the University of Vienna, a position Schlick would later hold — and the Cambridge philosopher Bertrand Russell. The idea of the logical positivists, such as A.J. Ayer and Rudolf Carnap, was to formulate the doctrine of phenomenalism in linguistic terms, so as to define out of existence references to such entities as physical objects in the external world. Sentences which contained terms such as "table" were to be translated into sentences which referred exclusively to either actual or possible sensory experiences.

Logical positivism and logical empiricism, which together formed neopositivism, was a movement in Western philosophy whose central thesis was verificationism, a theory of knowledge which asserted that only statements verifiable through empirical observation are meaningful. The movement flourished in the 1920s and 1930s in several European centers.

Moritz Schlick German philosopher

Friedrich Albert Moritz Schlick was a German philosopher, physicist, and the founding father of logical positivism and the Vienna Circle.

Bertrand Russell British philosopher, mathematician, historian, writer, and activist

Bertrand Arthur William Russell, 3rd Earl Russell, was a British philosopher, logician, mathematician, historian, writer, essayist, social critic, political activist, and Nobel laureate. At various points in his life, Russell considered himself a liberal, a socialist and a pacifist, although he also confessed that his sceptical nature had led him to feel that he had "never been any of these things, in any profound sense." Russell was born in Monmouthshire into one of the most prominent aristocratic families in the United Kingdom.

20th century American philosopher Arthur Danto asserted that "a phenomenalist, believ[es] that whatever is finally meaningful can be expressed in terms of our own [sense] experience.". [2] He claimed that "The phenomenalist really is committed to the most radical kind of empiricism: For him reference to objects is always finally a reference to sense-experience ... ." [3]

To the phenomenalist, objects of any kind must be related to experience. "John Stuart Mill once spoke of physical objects as but the 'permanent possibility of experience' and this, by and large, is what the phenomenalist exploits: All we can mean, in talking about physical objects or nonphysical objects, if there are any is what experiences we would have in dealing with them ... ." However, phenomenalism is based on mental operations. These operations, themselves, are not known from sense experience. Such non-empirical, non-sensual operations are the "...nonempirical matters of space, time, and continuity that empiricism in all its forms and despite its structures seems to require ... ." [3]

See for comparison Sensualism, to which phenomenalism is closely related.


Roderick Chisholm criticized the logical positivist version of phenomenalism in 1948. [4] C.I. Lewis had previously suggested that the physical claim "There is a doorknob in front of me" necessarily entails the sensory conditional "If I should seem to see a doorknob and if I should seem to myself to be initiating a grasping motion, then in all probability the sensation of contacting a doorknob should follow". [5] Chisholm objected that the statement "There is a doorknob..." does not entail the counterfactual statement, for if it were to do so, then it must do so without regard to the truth or falsity of any other statement; but suppose the following statement was true: "I am paralyzed from the neck down and experience hallucinations such that I seem to see myself moving toward the door". If this were true, Chisholm objected, then there could be a doorknob in front of me, I could seem to myself to see a doorknob, and I could seem to myself to be performing the correct sort of grasping motion, but with absolutely no chance of having a sensation of contacting the doorknob. Likewise, he objected that the statement that "The only book in front of me is red" does not entail the sensory statement "Redness would probably appear to me were I to seem to myself to see a book", because redness is not likely to appear under a blue light-bulb. Some[ who? ] have tried to avoid this problem by extending the conditions in the analysandum: instead of "There is a doorknob in front of me" one could have it that "There is a doorknob, and I am not paralyzed, etc." In response, Chisholm objects that if one complicates the analysandum, one must also complicate the analysans; in this particular case, that one must analyse in purely sensory terms what it means not to be paralyzed and so on, with respect to which the same problems would arise leading to an infinite regress.

Another common[ who? ] objection to phenomenalism is that in the process of eliminating material objects from language and replacing them with hypothetical propositions about observers and experiences, it seems to commit us to the existence of a new class of ontological object altogether: the sensibilia or sense-data which can exist independently of experience. Indeed, sense-data have been dismissed by some philosophers of mind, such as Donald Davidson, as mythological entities that are more troublesome than the entities that they were intended to replace.

A third common objection in the literature[ who? ] is that phenomenalism, in attempting to convert propositions about material objects into hypothetical propositions about sensibilia, postulates the existence of an irreducibly material observer in the antecedent of the conditional. In attempting to overcome this, some phenomenalists[ who? ] suggested that the first observer could be reduced by constructing a second proposition in terms of a second observer, who actually or potentially observes the body of the first observer. A third observer would observe the second and so on. In this manner we would end up with a "Chinese box series of propositions" of ever decreasing material content ascribed to the original observer. But if the final result is not the complete elimination of the materiality of the first observer, then the translational reductions that are proposed by phenomenalists cannot, even in principle, be carried out.

Another criticism is that the phenomenalist can give no satisfactory explanation of the permanent possibilities of experience. The question can be asked, "What are the counterfactual conditionals which ground the existence of objects true in virtue of?" One answer given by phenomenalists is that the conditionals are true in virtue of past regularities of experience. However, critics[ who? ] object that this answer leads to circularity: first our actual experience was meant to be explained by the possibility of experience, and now the possibility of experience is meant to be explained by our actual past experience. A further objection to the phenomenalist answer is that generally speaking, conditionals are not true in virtue of their past occurrences. This is because it seems that a conditional could be true even if it never actually obtained, and also past occurrences only confirm that a conditional is true, but never make it so.

Roderick Firth formulated another objection in 1950, stemming from perceptual relativity: White wallpaper looks white under white light and red under red light, etc. Any possible course of experience resulting from a possible course of action will apparently underdetermine our surroundings: it would determine, for example, that there is either white wallpaper under red light or red wallpaper under white light, and so on. On what basis are we to decide which of the hypotheses is the correct one if we are constrained to rely exclusively on sensibilia? [6]

Notable proponents

Related Research Articles

In philosophy, Idealism is the group of metaphysical philosophies that assert that reality, or reality as humans can know it, is fundamentally mental, mentally constructed, or otherwise immaterial. Epistemologically, Idealism manifests as a skepticism about the possibility of knowing any mind-independent thing. In contrast to Materialism, Idealism asserts the primacy of consciousness as the origin and prerequisite of material phenomena. According to this view, consciousness exists before and is the pre-condition of material existence. Consciousness creates and determines the material and not vice versa. Idealism believes consciousness and mind to be the origin of the material world and aims to explain the existing world according to these principles.

Metaphysics Branch of philosophy dealing with the nature of reality

Metaphysics is the branch of philosophy that examines the fundamental nature of reality, including the relationship between mind and matter, between substance and attribute, and between possibility 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.

Philosophy of perception

The philosophy of perception is concerned with the nature of perceptual experience and the status of perceptual data, in particular how they relate to beliefs about, or knowledge of, the world. Any explicit account of perception requires a commitment to one of a variety of ontological or metaphysical views. Philosophers distinguish internalist accounts, which assume that perceptions of objects, and knowledge or beliefs about them, are aspects of an individual's mind, and externalist accounts, which state that they constitute real aspects of the world external to the individual. The position of naïve realism—the 'everyday' impression of physical objects constituting what is perceived—is to some extent contradicted by the occurrence of perceptual illusions and hallucinations and the relativity of perceptual experience as well as certain insights in science. Realist conceptions include phenomenalism and direct and indirect realism. Anti-realist conceptions include idealism and skepticism.

In philosophy of science and in epistemology, Instrumentalism is a methodological view that ideas are useful instruments, and that the worth of an idea is based on how effective they are in explaining and predicting phenomena. Instrumentalism is a pragmatic philosophy of John Dewey that thought is an instrument for solving practical problems, and that truth is not fixed but changes as problems change. Instrumentalism is the view that scientific theories are useful tools for predicting phenomena instead of true or approximately true descriptions.

An unobservable is an entity whose existence, nature, properties, qualities or relations are not directly observable by humans. In philosophy of science, typical examples of "unobservables" are the force of gravity, causation and beliefs or desires.However, some philosophers also characterize all objects—trees, tables, other minds, microorganisms, every thing to which humans ascribe as the thing causing their perception—as unobservable.

Subjective idealism

Subjective idealism, or empirical idealism, is the monistic metaphysical doctrine that only minds and mental contents exist. It entails and is generally identified or associated with immaterialism, the doctrine that material things do not exist. Subjective idealism rejects dualism, neutral monism, and materialism; indeed, it is the contrary of eliminative materialism, the doctrine that all or some classes of mental phenomena do not exist, but are sheer illusions.

<i>Critique of Pure Reason</i> 1781 book by Immanuel Kant

The Critique of Pure Reason is a 1781 book by the German philosopher Immanuel Kant, in which the author seeks to determine the limits and scope of metaphysics. A heavily-revised second edition was published in 1787. Also referred to as Kant's "First Critique", it was followed by the Critique of Practical Reason (1788) and the Critique of Judgment (1790). In the preface to the first edition, Kant explains that by a "critique of pure reason" he means not "a critique of books and systems, but of the faculty of reason in general, in respect of all knowledge after which it may strive independently of all experience" and that he aims to reach a decision about "the possibility or impossibility of metaphysics". The First Critique is often viewed as a culmination of several centuries of early-modern philosophy, and an inauguration of modern philosophy.

Transcendental idealism Epistemology of the 18th-century German philosopher Immanuel Kant. Space and time are merely formal features of how we perceive objects, not things in themselves that exist independently of us.

Transcendental idealism is a doctrine founded by German philosopher Immanuel Kant in the 18th century. Kant's doctrine maintains that human experience of things is similar to the way they appear to us—implying a fundamentally subject-based component, rather than being an activity that directly comprehends the things as they are in themselves. The doctrine is most commonly presented as the idea that time and space are just human perceptions; they are not necessarily real concepts, just a medium through which humans internalize the universe.

Direct and indirect realism debate regarding corrospondence between experiences of the world and its reality

The question of direct or naïve realism, as opposed to indirect or representational realism, arises in the philosophy of perception and of mind out of the debate over the nature of conscious experience; the epistemological question of whether the world we see around us is the real world itself or merely an internal perceptual copy of that world generated by neural processes in our brain.

A sensorium (/sɛnˈsɔːrɪəm/) is the sum of an organism's perception, the "seat of sensation" where it experiences and interprets the environments within which it lives. The term originally entered English from the Late Latin in the mid-17th century, from the stem sens- ("sense"). In earlier use it referred, in a broader sense, to the brain as the mind's organ. In medical, psychological, and physiological discourse it has come to refer to the total character of the unique and changing sensory environments perceived by individuals. These include the sensation, perception, and interpretation of information about the world around us by using faculties of the mind such as senses, phenomenal and psychological perception, cognition, and intelligence.

<i>Prolegomena to Any Future Metaphysics</i> 1783 book by Immanuel Kant

Prolegomena to Any Future Metaphysics That Will Be Able to Present Itself as a Science is a book by the German philosopher Immanuel Kant, published in 1783, two years after the first edition of his Critique of Pure Reason. One of Kant's shorter works, it contains a summary of the Critique‘s main conclusions, sometimes by arguments Kant had not used in the Critique. Kant characterizes his more accessible approach here as an "analytic" one, as opposed to the Critique‘s "synthetic" examination of successive faculties of the mind and their principles.

"Critique of the Kantian philosophy" is a criticism Arthur Schopenhauer appended to the first volume of his The World as Will and Representation (1818). He wanted to show Immanuel Kant's errors so that Kant's merits would be appreciated and his achievements furthered.

Schema (Kant) Kantian term referring to how perceptions are matched to concepts

In Kantian philosophy, a transcendental schema is the procedural rule by which a category or pure, non-empirical concept is associated with a sense impression. A private, subjective intuition is thereby discursively thought to be a representation of an external object. Transcendental schemata are supposedly produced by the imagination in relation to time.

The analytic–synthetic distinction is a semantic distinction, used primarily in philosophy to distinguish propositions into two types: analytic propositions and synthetic propositions. Analytic propositions are true by virtue of their meaning, while synthetic propositions are true by how their meaning relates to the world. However, philosophers have used the terms in very different ways. Furthermore, philosophers have debated whether there is a legitimate distinction.

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In philosophy and certain models of psychology, qualia are defined to be individual instances of subjective, conscious experience. The term qualia derives from the Latin neuter plural form (qualia) of the Latin adjective quālis meaning "of what sort" or "of what kind" in a specific instance like "what it is like to taste a specific apple, this particular apple now".

In the philosophy of perception, the theory of sense data was a popular view held in the early 20th century by philosophers such as Bertrand Russell, C. D. Broad, H. H. Price, A. J. Ayer, and G. E. Moore. Sense data are taken to be mind-dependent objects whose existence and properties are known directly to us in perception. These objects are unanalyzed experiences inside the mind, which appear to subsequent more advanced mental operations exactly as they are.


  1. Wikisource-logo.svg Herbermann, Charles, ed. (1913). "Phenomenalism". Catholic Encyclopedia . New York: Robert Appleton Company.
  2. Danto, Arthur, Nietzsche as Philosopher, Ch. 3, § VI, Macmillan, 1965;
  3. 1 2 Danto, Arthur, Connections to the World, Ch. 27. Harper & Row, 1989, ISBN   0-06-015960-X
  4. Chisholm, R. "The Problem of Empiricism", The Journal of Philosophy 45 (1948): 512-7.
  5. C. I. Lewis, An Analysis of Knowledge and Valuation (LaSalle, Illinois: Open Court, 1946), pp. 240, 248-9.
  6. Firth, R. "Radical Empiricism and Perceptual Relativity", Philosophical Review. 1950