Dear Professor,
Your article
on the net titled "Perception and Reality" is indeed very enlightening.
However, after reading through it, some questions/comments have sprung
up in my mind which i would like to share with you :
Q1) " If our
brain perceives only the electrical signals of the stimulusand does not
come into contact with the stimulus itself, then does the stimulus actually
exist, can we be sure of that ?"
Q2) Is it possible
that these electrical signals could be coming from
some artificial
source ?
Q3) Does the
universe actually exist or is it just our perception(just like in a dream)
i.e. Are we beguiled by deception that there is a world outside the brain?
Q4) What about
the brain, can it also be itself, just a perception. If that is a possibility,
then who is this thing that is going through all these perceptions ?
Would greatly appreciate your response on the above.
Kashif Shirazi
Karachi, Pakistan
____________________________________________________________________________
Dear Mr. Kashif Shirazi:
First of all
let me tell you I feel honored to know that my article
"Perception
and Reality" has been read by a distinguished person from such a distant
country. I also thank you for your intriguing questions.But, initially
let us clarify an important point: we do not "perceive only electrical
signals of the stimulus" Actually, what we do perceive are electromagnetic
waves, not as waves, but as images and colors; vibrations,not as such,
but as sounds; chemical reactions, not as such, but as specific smells
and tastes. Because receptors of sensitive neurons located in our sensorial
apparatus allow us to do so. Then, these receptors convert the physical
expression of the stimulus (light, sound, smell etc...) into action
potentials which
transform them into electric signals that conduct the sensorial message
to specific processing areas inside the brain. Thus,electrical signs are
not related to the initial phase of perception, as you mention on your
first and second questions, but of subsequent stages of the process. Hoping
this is now clarified, let us try to answer the specific questions you
have formulated
1) Yes,
the stimulus actually exists. Otherwise, how could it be perceived by our
senses ?
2) Yes.
Mostly, we receive stimulus from natural sources, that surround us,like
the smell of a food, or from a distance, like the sun rays. But the stimulus
may also come from an artificial source, like an image transmitted
by a satellite.
3) Yes,
I believe the universe does exist. However I am not sure we
recognize our
universe as it really is, since we can only perceive it
through the
specific sensorial apparatus we have been provide by evolution. Let us
take color as an example. We, humans, can perceive several colors,within
a spectrum which ranges from red to violet. The dog, however, seems to
see everything only as gray. And even among us, some daltonic people, may
not distinguish colors as they are perceived by non-daltonic individuals.
And similar differences may occur regarding other senses. Therefore, each
species must have a particular conception of the universe.
4) This
remarkable question of yours is, in some way, related to the third one,
since both seem to favor illusion instead of reality.
They bring to
my mind the theory of "Radical Idealism" proposed by Berkeley,an Anglican
Bishop, for whom nothing can be said with certainty about the universe,
because it may be only a fantasy, an illusion created by our minds. By
the way, this subject makes me recall an extraordinary "game of words",
that, supposedly, took place between the spiritualist and idealist Berkelely
and the famous scientist and convicted materialist David Hume:Hume said:
There is no mind? It does not matter.Berkeley answered: There is
no matter ? It does not mind Back to your question: perhaps I could accept
that the universe and the brain are just perceptions, illusions, nothing
else.
Yes, I could.
But I do not. I do believe that the universe exists and that the brain
is not a perception, but a concrete organ, capable of having perceptions.
However, if I am wrong, then, perhaps, we could regard ourselves and,consequently,
our brains, as well as the whole universe we live in, as being just a dream
(or a nightmare?) dreamed by a superior conscience - God ?
But, by God,
I feel I am not wrong !
Hopping my scientific
and also philosophical remarks have satisfied your highly philosophical
questionings and doubts,I remain.
Yours sincerely
Jorge Martins
de Oliveira
Copyright
Silvia
Helena Cardoso, PhD
Correspondence