The problem of other minds is the philosophical problem of determining how we know that there are minds associated with the bodies we see walking around among us. This is more specifically a problem of epistemology. The Philosopher (detail), by Rembrandt Philosophy is a study that includes various diverse subfields such as aesthetics, epistemology, ethics, logic, and metaphysics. ... To meet Wikipedias quality standards and appeal to a wider international audience, this article may require cleanup. ... With regard to living things, a body is the integral physical material of an individual, and contrasts with soul, personality and behavior. ... Epistemology is an analytic branch of philosophy which studies the nature, origin, and scope of knowledge. ...

The problem can more accurately be expressed by breaking it into several steps.

1. We cannot know that when you look at a red object you have the same perception of red that I do (i.e. We cannot know that if I were to inherit your state of mind at that time, I would not call the sensation green)
2. Therefore, we cannot know that other people have any sensations at all as opposed to automatic nervous reaction.
3. We can never directly know another's mental state.

Conclusion: We can never know that there exist any other minds but our own. This can lead to the philosophical position known as solipsism. This article or section contains information that has not been verified and thus might not be reliable. ...

In response to this problem there have been different areas of attack.

The reductionist viewpoint, supported by John McDowell and others, has tried to tackle the first two propositions 1 and 2 (above), by putting forth certain modes of expression (such as being in pain) as privileged and allowing us direct access to the other's mind. Thus, although they would admit from the problem of pretense, that at no one time can we claim to have access to another's mental state, they are not permanently unavailable to us. Reductionism in philosophy describes a number of related, contentious theories that hold, very roughly, that the nature of complex things can always be reduced to (be explained by) simpler or more fundamental things. ... John McDowell (born 1942) is a contemporary philosopher, formerly a fellow of University College, Oxford and now University Professor at the University of Pittsburgh. ...

Counter to the reductionist argument would be a more biological theory (and somewhat materialistic viewpoint). Take the eye and the perception of color. The light-sensing cone cells of the retina that respond to the portion of the electromagnetic spectrum designated as "red" are tuned similarly in every person tested, so we might expect all people to experience red in the same way. However, we also know that some people are missing certain (or all of) types of cone cells in the eye; thus giving rise to color blindness and other such visual variances. Similarly, differences in the distribution of brain cells and dendritic connections (among many other potential variances) could give rise to different mental states for the same stimulus. Cross-culturally, when people have a word for red, they agree with other cultures on which wavelengths of light best fit the term "red" (the same wavelengths that primarily excite the cone cells which detect red, and the red/green channel to the brain). Yet even if human eyes and brains may be built in such a way that the same wavelengths stand out for everybody, still it is conceivable that for different individuals these wavelengths could evoke experiences that differ. In particular, one external stimulus may give different experiences to the same individual according to which eye is used. In philosophy, materialism is that form of physicalism which holds that the only thing that can truly be said to exist is matter; that fundamentally, all things are composed of material and all phenomena are the result of material interactions. ... An eye is an organ of vision that detects light. ... Cells in culture, stained for keratin (red) and DNA (green). ... Human eye cross-sectional view. ... Legend: γ = Gamma rays HX = Hard X-rays SX = Soft X-Rays EUV = Extreme ultraviolet NUV = Near ultraviolet Visible light NIR = Near infrared MIR = Moderate infrared FIR = Far infrared Radio waves: EHF = Extremely high frequency (Microwaves) SHF = Super high frequency (Microwaves) UHF = Ultrahigh frequency VHF = Very high frequency HF = High frequency... Color blindness in humans is the inability to perceive differences between some or all colors that other people can distinguish. ... Drawing by Santiago Ramón y Cajal of cells in the pigeon cerebellum. ... (The term dendrite may also refer to the metallurgical dendrite. ...

Lastly, some people see the very fact that we can discuss the problem of other minds and relate with one another on this existential angst as proof against solipsism. These individuals argue that all minds are fundementally connected, we all differ in our own universes of thought but the overall universe is constant and binds us together. For example when two people are talking and come to exactly the same conclusion at the same time, minds are interlinked, bound by the body until death where they become part of a mind at large. A mind at large is capable of percieving everything in the universe at the same time. The mind at large, that we are all capable of, has to be funneled through the reducing valve of the brain and nervous system. What comes out the other end is a measly trickle of the kind of consciousness which will help us to stay alive (Adeous Huxley- Doors of Perception, 23).

Literature

• Wisdom, John, Other Minds (1952)
• Dennett, D.C., Brainstorms: Philosophical Essays on Mind and Psychology (1978)

John Wisdom (1904-1993) was an ordinary language philosopher and philosopher of mind. ... 1952 (MCMLII) was a Leap year starting on Tuesday (link will take you to calendar). ... Daniel Dennett Daniel Clement Dennett (born March 28, 1942) is a prominent American philosopher. ... 1978 (MCMLXXVIII) was a common year starting on Sunday (the link is to a full 1978 calendar). ...

See also

• color perception
• psychophysics
• qualia
• autism