This essay has a total of 787 words and 4 pages.


Descartes is famed by is familiar notion, "I think therefore I am (Cogito, ergo sum.)."
It is a conclusion he has reached in his second meditation after much deliberation on the
existence of anything certain. After he discovers his ability to doubt and to understand
, he is able to substantiate his necessary existence as a consequence. What we doubt or
understand may not ultimately correspond, but we can never be uncertain that we are in the
process of thought. This idea is a major component in DescartesŐ proof of the external

He relies on the existence of a non-deceiving God to ensure that an external world exists
after calling it into doubt by the invocation of the dream argument. In this argument,
Descartes suggests the possibility that none of our ideas are caused by external objects
and therefore, such objects may not exist. He also raises the idea of a demon that may
deceive us and allow us to perceive what is not really there. Although he assures himself
of his own existence by his modes of thought, he remains uncertain of the reality of an
external world. He doubts whether there is anything of material substance that provokes
thought within him rather than it being conceived in his mind completely independent of
anything else. Descartes then considers those reasons that have inclined him to believe
these material things exist in the past.

"I know by experience that these ideas do not depend upon my will, nor consequently upon
myself, for often I notice them against my will... I feel heat, and therefore I believe
that this feeling or idea of heat comes to me from something other than myself, namely
from the fire I am near. Nothing is more obvious than the judgment that this object
(rather than something else) grafts its likeness on to me."

Since however, he has called upon anything to be false that provokes any doubt he does not
believe this explanation to be enough for the proof of the external world. Relying on
this sort of natural impulse has led him astray in the past, so what is to keep it from
happening all the time. He also calls upon the dream argument in this instance. Ideas
come to be in dreams independent of external objects and perhaps this is true of ideas
when we are awake.

It seems that Descartes finds it necessary to first establish the existence of a
non-deceiving God before he can be assured of the existence of anything beyond himself and
his mode of thought. He does this by the rationalization that his perception of God is
that of a perfect being. In order for a being to be perfect it must exist. Since he
himself is an imperfect being, he can not conceive the idea of perfection on his own.
Continues for 2 more pages >>