FREE ESSAY ON COMPARISON OF DESCARTES AND HEIDEGGER

COMPARISON OF DESCARTES AND HEIDEGGER

According to Descartes, the essence of material substance is simply extension, the
property of filling up space. (Med. V) So solid geometry, which describes the possibility
of dividing an otherwise uniform space into distinct parts, is a complete guide to the
essence of body. It follows that there can be in reality only one extended substance,
comprising all matter in a single spatial whole. From this, Descartes concluded that
individual bodies are merely modes of the one extended being, that there can be no space
void of extension, and that all motion must proceed by circular vortex. Thus, again, the
true nature of bodies is understood by pure thought, without any information from the
senses. 
1. The Dream Problem 
Second, Descartes raised a more systematic method for doubting the legitimacy of all
sensory perception. Since my most vivid dreams are internally indistinguishible from
waking experience, he argued, it is possible that everything I now perceive to be part of
the physical world outside me is in fact nothing more than a fanciful fabrication of my
own imagination. On this supposition, it is possible to doubt that any physical thing
really exists, that there is an external world at all. (Med. I) 
Severe as it is, this level of doubt is not utterly comprehensive, since the truths of
mathematics and the content of simple natures remain unaffected. Even if there is no
material world (and thus, even in my dreams) two plus three makes five and red looks red
to me. In order to doubt the veracity of such fundamental beliefs, I must extend the
method of doubting even more hyperbolically.
In the Sixth Meditation, Descartes finally tried to eliminate the dream problem by
proving that there is a material world and that bodies do really exist. His argument
derives from the supposition that divinely-bestowed human faculties of cognition must
always be regarded as adequately designed for some specific purpose. Since three of our
faculties involve representation of physical things, the argument proceeds in three
distinct stages. (Med. VI) 
First, since the understanding conceives of extended things through its comprehension of
geometrical form, it must at least be possible for things of this sort to exist. Second,
since the imagination is directed exclusively toward the ideas of bodies and of the ways
in which they might be purposefully altered, it is probable that there really are such
things. Finally, since the faculty of sense perception is an entirely passive ability to
receive ideas of physical objects produced in me by some external source outside my
control, it is certain that such objects must truly exist. 
The only alternative explanation for perception, Descartes noted, is that god directly
puts the ideas of bodies into my mind without there acutally being anything real that
corresponds to them. (This is precisely the possibility that Malebranche would later
accept as the correct account of the material world.) But Descartes supposed that a
non-deceiving god would never maliciously give me so complete a set of ideas without also
causing their natural objects to exist in fact. Hence, the bodies I perceive do really
exist.
Among the physical objects I perceive are the organic bodies of animals, other human
beings, and myself. So it is finally appropriate to consider human nature as a whole: how
am I, considered as a thinking thing, concerned with the organism I see in the mirror?
What is the true relation between the mind and the body of any human being? According to
Descartes, the two are utterly distinct. 
The Sixth Meditation contains two arguments in defence of Cartesian dualism: First, since
the mind and the body can each be conceived clearly and distinctly apart from each other,
it follows that god could cause either to exist independently of the other, and this
satisfies the traditional criteria for a metaphysical real distinction. (Med. VI) Second,
the essence of body as a geometrically defined region of space includes the possibility
of its infinite divisibility, but the mind, despite the variety of its many faculties and
operations, must be conceived as a single, unitary, indivisible being; since incompatible
properties cannot inhere in any one substance, the mind and body are perfectly distinct.
(Med. VI) 
This radical separation of mind and body makes it difficult to account for the apparent
interaction of the two in my own case. In ordinary experience, it surely seems that the
volitions of my mind can cause physical movements in my body and that the physical states
of my body can produce effects on my mental operations. But on Descartes's view, there
can be no substantial connection between the two, nor did he believe it appropriate to
think of the mind as residing in the body as a pilot resides within a ship. Although he
offered several tenatative suggestions in his correspondence with Princess Elizabeth,
Descartes largely left for future generations the task of developing some reasonable
account of volition and sensation, either by securing the possibility of mind-body
interaction or by proposing some alternative explanation of the appearances.