thought you would enjoy this/Bill

[Guest guest]

B:Howdy Stranger!

Where the heck have you been?

Care to hang around for awhile?

 

Howdy Bill! Been back at the saloon

drinking a mug of pure sensations.

Just feeling what I feel, sensing it

dissolve into thin air, emptiness,

space. Those sensations are the illusive

bricks which build the phantom castle

call reality, ideas, cognition, truth and

the like.

You been keeping those desperadoes

at bay. Good to a Marshall at Dodge, so an

old cowhand can enjoy a mug in peace.

 

From Wikepedia

 

Philosophical ideas about perception

The most common theory of perception is naïve realism in which people

believe that what they perceive is things in themselves. Children

develop this theory as a working hypothesis of how to deal with the

world. Many people who have not studied biology carry this theory into

adult life and regard their perception to be the world itself rather

than a pattern that overlays the form of the world. Thomas Reid took

this theory a step further, he realised that sensation was composed of

a set of data transfers but declared that these were in some way

transparent so that there is a direct connection between perception and

the world. This idea is called Direct Realism. Direct Realism has

become popular in recent years with the rise of postmodernism and

Behaviourism. Direct Realism does not clearly specify the nature of the

bit of the world that is an object in perception, especially in cases

where the object is something like a silhouette.

The succession of data transfers that are involved in perception

suggests that somewhere in the brain there is a final set of activity,

called sense data, that is the substrate of the percept. Perception

would then be some form of brain activity and somehow the brain would

be able to perceive itself. This concept is known as indirect realism.

In Indirect Realism it is held that we can only be aware of external

objects by being aware of representations of objects. This idea was

held by John Locke and Immanuel Kant. The common argument against

indirect realism, used by Gilbert Ryle amongst others, is that it

implies a homunculus or Ryle's regress where it appears as if the mind

is seeing the mind in an endless loop. This argument assumes that

perception is entirely due to data transfer and classical information

processing. This assumption is highly contentious (see strong AI) and

the argument can be avoided by proposing that the percept is a

phenomenon that does not depend wholly upon the transfer and

rearrangement of data.

Direct realism and indirect realism are known as 'realist' theories of

perception because they hold that there is a world external to the

mind. Direct realism holds that the representation of an object is

located next to, or is even part of, the actual physical object whereas

indirect realism holds that the representation of an object is brain

activity. Direct realism proposes some as yet unknown direct connection

between external representations and the mind whilst indirect realism

requires some feature of modern physics to create a phenomenon that

avoids infinite regress. Indirect realism is consistent with

experiences such as:

binding, dreams, imaginings, hallucinations, illusions, the resolution

of binocular rivalry, the resolution of multistable perception, the

modelling of motion that allows us to watch TV, the sensations that

result from direct brain stimulation, the update of the mental image by

saccades of the eyes and the referral of events backwards in time

whereas direct realism argues either that these experiences do not

occur or avoids the problem by defining perception as only those

experiences that are consistent with direct realism.

Apart from the realist theories of perception there are also

anti-realist theories. There are two varieties of anti-realism:

Idealism and Skepticism. Idealism holds that we can only be aware of

mental things whereas skepticism holds that because we never perceive

external objects directly we can never know for certain whether they

exist. One of the most influential proponents of idealism was George

Berkeley who maintained that everything was mind or dependent upon

mind. Berkeley's idealism has two main strands, phenomenalism in which

physical events are viewed as a special kind of mental event and

subjective idealism. David Hume is probably the most influential

proponent of skepticism.

The philosophy of perception is very closely related to a branch of

philosophy known as epistemology, the theory of knowledge, and many of

the ideas presented above are also discussed under this heading.

[edit]

 

Cognitive processing and epiphenomenalism

Perception is sometimes referred to as a cognitive process in which

information processing is used to transfer information from the world

into the brain and mind where it is further processed and related to

other information. Some philosophers and psychologists propose that

this processing gives rise to particular mental states (cognitivism)

whilst others envisage a direct path back into the external world in

the form of action (radical behaviourism).

Many eminent behaviourists such as John B. Watson and B.F. Skinner have

proposed that perception acts largely as a process between a stimulus

and a response but despite this have noted that Ryle's " ghost in the

machine " of the brain still seems to exist. As Skinner wrote:

" The objection to inner states is not that they do not exist, but that

they are not relevant in a functional analysis " Skinner 1953.

This view, in which experience is thought to be an incidental

by-product of information processing, is known as epiphenomenalism.

[edit]

 

Perceptual space

Another aspect of perception that is common to both realists and

anti-realists is the idea of mental or perceptual space. David Hume

considers this at some length and concludes that things appear extended

because they have the attributes of colour and solidity. A popular

modern philosophical view is that the brain cannot contain images so

our sense of space must be due to the actual space occupied by physical

things. However, as Rene Descartes noticed, perceptual space has a

projective geometry, things within it appear as if they are viewed from

a point and are not simply objects arranged in 3D. Mathematicians now

know of many types of projective geometry such as complex Minkowski

space that might describe the layout of things in perception (see

Peters (2000)). It is also known that many parts of the brain contain

patterns of electrical activity that correspond closely to the layout

of the retinal image (this is known as retinotopy). There are indeed

images in the brain but how or whether these become conscious

experience is a mystery (see McGinn (1995)).

[edit]