Descartes applied illusion argument, dreaming argument, and evil genius argument
that is called "method of doubt" to achieve his goals: Mind and body
are two different substances, the complete separation of the mental world and
the physical world. Once, he claims that even awake or asleep, two plus three is
always five. Even evil genius fakes us, we probably think two plus three is four
but in fact it always exist as five and it is always true. Lets look at this
example: If I think that it's sunny outside, I can be wrong about sun but I
cannot be wrong about my thinking that it's sunny. So, no matter if I am being
deceived or dreaming either way I am thinking, which is certain knowledge. Even
though our senses aren't reliable, when we see things we still have the
experience of seeing that thing. Even if in a dream, an apple is still
experienced as our definition of an apple. An apple in a dream will be still
looked and smelled the same as an apple to us in a wake because the experience
is the same. Because we really don't definitely know if we are awake or asleep
at any time we can only say that the experience of the apple is certain in our
minds. For example while one is in deep sleep we do not know whether we are
thinking or not. When we wake up we may remember a dream or two but when we
think about it they may only add up to about five minutes in length even though
we know we were asleep for eight hours. There is all of that time when we don't
remember what we were thinking or if we were even thinking at all. When using
this argument as an objection to the "I think, therefore I am" we say
that it is impossible to not be thinking because to stop thinking is to no
longer exist. Descartes would say that even though we may not remember that we
were thinking, we were thinking nonetheless. There are many things which we
don't remember. I don't remember being born but that does not mean that I wasn't
thinking at the time. During the night we might be woken up by a loud sound, but
after we wake up we might not remember a thing. It still remains that even
though we can't remember any thought before we wake, we know that there was
because we heard the noise and woke up. We still have experiences while asleep
whether they are dreams or experience of hot or cold or a smell or a sound. We
know we still experience them because they arouse us to wakefulness and
therefore are experience while in deep sleep. Therefore, it is possible that
while in deep sleep we might not remember everything we thought but we are still
thinking or else we would probably never wake up. Think about how you wake up at
any time and it is obvious that some thought is involved. And the wakefulness by
loud sound or disturbance is also called reaction but not the interaction of
body and mind. Mind is conscious and non-spatial and body is spatial but not
conscious. While separate, these two substances interact. The mind, which can't
be doubt or divided or extended, no shape but it is to think in the pursuit of
knowledge and the body, in return, can be doubt, divided, extended, occupied
space, is a place containing brain that generates thought. Descartes asserts
that the mind and body are separable and infinite by using his method of doubt
to show that he could not doubt the existence of his mind. As long as we think,
we are existing because we must exist first then to think. As doubting involved
thought, and thought needs a consciousness to think it, Descartes was sure that
he could not doubt his mind existed: "I think therefore I am". He
claims to know what a thinking think is, and he regards we are as thinking
thing. The Cartesian Dualism is still having problem of explanation of how mind
and body interact or why mind does not stuck in body or mind control body.
Insisting that the mental representation does not represent the physical is very
confused and does not completely explain the issues. Descartes insists that God
is responsible for these interactions and only He knows how the process works.
So, reaction is the interaction between mind and body? The answer is
"no", because reaction is happened before we think what we should do.
Therefore, mind does not control completely body but partial of it. Descartes
agrees that the mind, characterized by mental substance, and the body,
characterized by physical substance, are separable and immortal. However,
Descartes questions whether the physical body even really exists at all.
Although these philosophers do not have a clear understanding of how the mind
and body, which are separate entities, interact, they clearly agree that mental
and physical are separable and immortal.