Reality and how your brain represents it.

One matter that deserves attention concerns how we understand the
relationship between the brain’s models of the world and the world itself. In
particular, what can we learn about the fidelity of the brain’s representations relative
to the things that are represented?  An assortment of interconnected problems
resides in this domain, and it will be useful to extract the most troublesome for
further dissection.
According to conventional wisdom,  some properties that are represented by
the brain as in the world are not genuinely in the world at all, but are mere products
of brain activity. The standard examples are colors, smells, and sounds.



Galileo (1564-1642) was perhaps the first to postulate this distinction.

 He aimed to give an explanation for the fact that way the world appears in experience
may not be the way the world really is, and that we can discover how the world really
is, despite how it may appear to us

Galileo, and later John Locke (1632-1704),  saw wisdom in distinguishing
between real-world properties (primary qualities) and merely brain-constructed
properties (secondary qualities).


There is no brain-independent or representation-free
access to reality. If color and smell representations are the brain’s causal response
to certain external stimuli, then so are spatial representations and motion
representations. The brain cannot directly compare its representation of the external
world with the external world itself, as one might compare the on-stage Wizard of Oz
with the man behind the curtain.



Here then is the dilemma: if the distinctions between the inner-me and outerworld are made within the brain’s representational models, then how does the
distinction between brain-constructed properties and real-world properties get
purchase.

At the bottom of the slippery
slope is the proposition that the so-called external world is, after all, nothing other
than my idea of an external world. Ideas are the only things there really are.
Furthermore, my apparently physical brain also must be nothing but an idea. In this

case, only nonphysical minds -- only constellations of ideas --  genuinely exist.
Classically, this view is known as idealism, and it is what awaits us at the bottom of
the slope.


Contrary to naïve realism, the conclusion that there is a perfect match
between reality and representation is untenable. Nevertheless, a reasonable solution
can be found by looking for less exacting and more flexible relationships, such as an
informational correspondence between brains and the world.


Brain models of the external world map the
causal structure of the world with varying degrees of fidelity and detail. A frog’s brain
maps rather less of the causal structure of the world than a raven’s brain; an infant’s
brain maps less of the causal structure of the world than an adult’s brain;
prescientific human brains map less of the causal structure of the world than
scientifically trained brains.

The above has been extracted from

NEURAL WORLDS AND REAL WORLDS
Patricia S. Churchland & Paul M. Churchland
http://philosophyfaculty.ucsd.edu/faculty/pschurchland/papers/nature02neuralworldsreal.pdf


Website for exploring visual phenomena and visual illusions:
Donald D. Hoffman:
http://www.aris.ss.uci.edu/cogsci/personnel/hoffman/Applets/index.html