The homunculus argument is a fallacy

Fallacy

In logic and rhetoric, a fallacy is usually an incorrect argumentation in reasoning resulting in a misconception or presumption. By accident or design, fallacies may exploit emotional triggers in the listener or interlocutor , or take advantage of social relationships between people...

 arising most commonly in the theory of vision

Visual perception

Visual perception is the ability to interpret information and surroundings from the effects of visible light reaching the eye. The resulting perception is also known as eyesight, sight, or vision...

. One may explain (human) vision by noting that light

Light

Light or visible light is electromagnetic radiation that is visible to the human eye, and is responsible for the sense of sight. Visible light has wavelength in a range from about 380 nanometres to about 740 nm, with a frequency range of about 405 THz to 790 THz...

 from the outside world forms an image on the retina

Retina

The vertebrate retina is a light-sensitive tissue lining the inner surface of the eye. The optics of the eye create an image of the visual world on the retina, which serves much the same function as the film in a camera. Light striking the retina initiates a cascade of chemical and electrical...

s in the eye

Human eye

The human eye is an organ which reacts to light for several purposes. As a conscious sense organ, the eye allows vision. Rod and cone cells in the retina allow conscious light perception and vision including color differentiation and the perception of depth...

s and something (or someone) in the brain

Human brain

The human brain has the same general structure as the brains of other mammals, but is over three times larger than the brain of a typical mammal with an equivalent body size. Estimates for the number of neurons in the human brain range from 80 to 120 billion...

 looks at these images as if they are images on a movie screen (this theory of vision is sometimes termed the theory of the Cartesian Theater

Cartesian theater

The Cartesian theater is a derisive term coined by philosopher Daniel Dennett to pointedly refer to a defining aspect of what he calls Cartesian materialism, which he considers to be the often unacknowledged remnants of Cartesian dualism in modern materialistic theories of the mind.Descartes...

: it is most associated, nowadays, with the psychologist David Marr, see also: solipsism

Solipsism

Solipsism is the philosophical idea that only one's own mind is sure to exist. The term comes from Latin solus and ipse . Solipsism as an epistemological position holds that knowledge of anything outside one's own mind is unsure. The external world and other minds cannot be known, and might not...

). The question arises as to the nature of this internal viewer. The assumption here is that there is a 'little man' or 'homunculus

Homunculus

Homunculus is a term used, generally, in various fields of study to refer to any representation of a human being. Historically, it referred specifically to the concept of a miniature though fully formed human body, for example, in the studies of alchemy and preformationism...

' inside the brain 'looking at' the movie.

The reason why this is a fallacy may be understood by asking how the homunculus 'sees' the internal movie. The obvious answer is that there is another homunculus inside the first homunculus's 'head' or 'brain' looking at this 'movie'. But how does this homunculus see the 'outside world'? In order to answer this, we are forced to posit another homunculus inside this other homunculus's head and so forth. In other words, we are in a situation of infinite regress

Infinite regress

An infinite regress in a series of propositions arises if the truth of proposition P1 requires the support of proposition P2, the truth of proposition P2 requires the support of proposition P3, .....

. The problem with the homunculus

Homunculus

Homunculus is a term used, generally, in various fields of study to refer to any representation of a human being. Historically, it referred specifically to the concept of a miniature though fully formed human body, for example, in the studies of alchemy and preformationism...

 argument is that it tries to account for a phenomenon in terms of the very phenomenon that it is supposed to explain.

Homunculus arguments in terms of Rules

Another example is with cognitivist

Cognitivism (psychology)

In psychology, cognitivism is a theoretical framework for understanding the mind that came into usage in the 1950s. The movement was a response to behaviorism, which cognitivists said neglected to explain cognition...

 theories that argue that the human brain uses 'rules' to carry out operations (these rules often conceptualised as being like the algorithms of a computer program

Computer program

A computer program is a sequence of instructions written to perform a specified task with a computer. A computer requires programs to function, typically executing the program's instructions in a central processor. The program has an executable form that the computer can use directly to execute...

). For example, in his work of the '50s, '60s and '70s Noam Chomsky

Noam Chomsky

Avram Noam Chomsky is an American linguist, philosopher, cognitive scientist, and activist. He is an Institute Professor and Professor in the Department of Linguistics & Philosophy at MIT, where he has worked for over 50 years. Chomsky has been described as the "father of modern linguistics" and...

 argued that (in the words of one of his books) human beings use Rules and Representations (or to be more specific, rules acting on representations) in order to cognise (more recently Chomsky has abandoned this view: c.f. the Minimalist Program

Minimalist program

In linguistics, the Minimalist Program is a major line of inquiry that has been developing inside generative grammar since the early nineties. It started with a 1993 paper by Noam Chomsky....

).

Now, in terms of (say) chess, the players are given 'rules' (i.e. the rules of chess) to follow. So: who uses these rules? The answer is self-evident: the players of the game (of chess) use the rules: it's not the case (obviously) that the rules themselves play chess. The rules themselves are merely inert marks on paper until a human being reads, understands and uses them. But what about the 'rules' that are, allegedly, inside our head (brain)? Who reads, understands and uses them? Again, the implicit answer is (and, some would argue, must be) a 'homunculus': a little man who reads the rules of the world and then gives orders to the body to act on them. But again we are in a situation of infinite regress

Infinite regress

An infinite regress in a series of propositions arises if the truth of proposition P1 requires the support of proposition P2, the truth of proposition P2 requires the support of proposition P3, .....

, because this implies that the homunculus has cognitive process that are also rule bound, which presupposes another homunculus inside its head, and so on and so forth. Therefore, so the argument goes, theories of mind that imply or state explicitly that cognition is rule

Rule of inference

In logic, a rule of inference, inference rule, or transformation rule is the act of drawing a conclusion based on the form of premises interpreted as a function which takes premises, analyses their syntax, and returns a conclusion...

 bound cannot be correct unless some way is found to 'ground' the regress.

This is important because it is often assumed in cognitive science

Cognitive science

Cognitive science is the interdisciplinary scientific study of mind and its processes. It examines what cognition is, what it does and how it works. It includes research on how information is processed , represented, and transformed in behaviour, nervous system or machine...

 that rules and algorithms are essentially the same: in other words, the theory that cognition is rule bound is often believed to imply that thought (cognition

Cognition

In science, cognition refers to mental processes. These processes include attention, remembering, producing and understanding language, solving problems, and making decisions. Cognition is studied in various disciplines such as psychology, philosophy, linguistics, and computer science...

) is essentially the manipulation of algorithms, and this is one of the key assumptions of some varieties of artificial intelligence

Artificial intelligence

Artificial intelligence is the intelligence of machines and the branch of computer science that aims to create it. AI textbooks define the field as "the study and design of intelligent agents" where an intelligent agent is a system that perceives its environment and takes actions that maximize its...

.

Homunculus arguments are always fallacious

Fallacy

In logic and rhetoric, a fallacy is usually an incorrect argumentation in reasoning resulting in a misconception or presumption. By accident or design, fallacies may exploit emotional triggers in the listener or interlocutor , or take advantage of social relationships between people...

 unless some way can be found to 'ground' the regress. In psychology

Psychology

Psychology is the study of the mind and behavior. Its immediate goal is to understand individuals and groups by both establishing general principles and researching specific cases. For many, the ultimate goal of psychology is to benefit society...

 and philosophy of mind

Philosophy of mind

Philosophy of mind is a branch of philosophy that studies the nature of the mind, mental events, mental functions, mental properties, consciousness and their relationship to the physical body, particularly the brain. The mind-body problem, i.e...

, 'homunculus arguments' (or the 'homunculus fallacies') are extremely useful for detecting where theories of mind

Mind

The concept of mind is understood in many different ways by many different traditions, ranging from panpsychism and animism to traditional and organized religious views, as well as secular and materialist philosophies. Most agree that minds are constituted by conscious experience and intelligent...

 fail or are incomplete.

The Homunculus fallacy is closely related to Ryle's regress

Ryle's regress

In philosophy, Ryle's regress is a classic argument against cognitivist theories, and concludes that such theories are essentially meaningless as they do not explain what they purport to...

.