On Jul 31, 1:55 pm, George Hammond notspam.org> wrote:

About as possible as that you are in a fake world like the matrix and
everything is an illusion. It is only a lucky guess whether you are or
not.

Skeptic Braino

Imagime that a superscientist invents machine--we shall call it a
"braino," - that enables him to produce hallucianations in certain
subjects . The machine operates by influencing the brain of a subject
who wears a special cap, called a "braino cap." when the braino cap is
placed on a subject's head, the operator of the braino can affect his
brain so as to produce any hallucination in the subject that the
operator wishes. The braino is a hallucination-producing machine. The
hallucinations produced by it may be as incomplete, systematic, and
coherent as the operator of the branio desires to make them.

Epistemist
The present argument starts from the premise that the braino is a
logical possibility, and consequently that there should be
hallucinations that are coherent, complete, and systematic in every
way. from the premise of logical possibility, she arrives at the
conclusion that we in fact have no way of telling whether or not we
are hallucinating.

Skeptic
If the braino is a logical possibility, then how can we tell that
hallucinations are not in fact so hard to detect? On the contrary, we
may suffer hallucinations that we cannot detect. If it is logically
possible that hallucinations should be coherent, complete, and
systematic in every way, then there is no way of detecting at any
moment that we are not suffering from a hallucionation.

.....explain how we can tell that we are not hallucinating. Our braino
argument was intended to establish that we can never tell this, even
if we can sometimes tell that we are hallucinating.

.....Consider some perceptual belief that you would maintain does not
from hallucinations. what experiences guarantee this? Indeed, what
experiences provide you with any evidence of it?

.....Notice that whatever experience you indicate, the braino argument
will be quite sufficient to prove that such an experience is no
guarantee against hallucianation. All we need do is imagine that you
have, unknown to yourself, the braino cap on your head. the operator
of the braino is producing the very experiences you claim guarantee
that you are not hallucinating.

Dr. O (Skeptic)
Imagine that all people are controlled by the braino and that the
machine is run by some evil being, Dr. O, who plots to keep us
completely in error through hallucinations.

Dr. O does not wish to be detected, so he supplies hallucinations that
are coherent, complete, and systematic. Indeed, the hallucinations he
produced in us are a PERFECT COUNTERFEIT OF REALITY.

Dr. O (Skeptic)
Our experiences fulfill our expectations and contain no more surprises
than we would expect from reality. But is it not reality we
experience; our perceptual beliefs about the world are quite mistaken,
for the source of our experiences is a mere machine, the braino, which
creates hallutionations. In such a predicament we might have just the
sort of perceptual beliefs we now have, based on experiences exactly
similar to those we now have. But our perceptual beliefs would be
altogether false.

Braino (Skeptic)
The imagined situation is exactly similar to ours with respect to the
reasons or evidence we would have for our perceptual beliefs.
Experience is virtually the same in both cases. Consequently, if we
lack knowledge in one situation, we must surely lack it in the other.
Obviously, we lack knowledge when we are controlled by the braino, for
then our perceptual beliefs are false. Hence, we also lack knowledge
in our present situation. More precisely, our perceptual beliefs fail
to constitute knowledge in either case.

(Skeptic)
We believe that we are not controlled by such a machine, and if we are
fortunate in this belief, then no doubt many of our perceptual beliefs
are true. It is, however, good fortune and not good evidence that we
should thank for correctness of these beliefs.

We are just lucky if there is no Dr. O controlling us with a braino;
and from that good fortune may result the further good fortune that
most of our perceptual beliefs are true. it is just a matter of luck,
however, and nothing epistemologically more glorious than that.

If a belief is true as a result of luck, then it is a lucky guess--not
knowledge.

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