René Descartes' Meditations on First Philosophy: the Outside World Problem

In the 5th The first paragraph Descartes Meditation leads one to the contemplation of the phenomenon of the dream a second basic question. Was in the 3rd Paragraph, sensory perception as a basis of knowledge called into question, so is now the one subject on knowledge-oriented, cognitive state of the doubt.
In the dream, and reflects Descartes, he experienced "sometimes even harder to believe, (...) as those in the waking state (AT VII, 19). Those are the crazy, insane, mental, of which state he is still so in paragraph 4 far believes. Just as those in waking an attitude have to the world, based no doubt on the sane people on imagination, there is now Descartes, who says in a dream to experience more crazier. More often, however, are in a dream state in which he experiences from everyday life. For example, "to be here, to have the skirt and sitting on the stove" (AT VII, 19). First, he expects to be able to distinguish between dream and waking clearly. The dream example is nothing more than memories because the "head I move (Descartes, note the author) is not encompassed by sleep" (AT VII, 19). The withdrawal of this "argument" follows immediately, because even in his dreams he believes such to have thought . As a result, it is found, for Descartes, therefore, not possible to secure features "can be distinguished from the sleeping guards" by the (AT VII, 19).

In the first Descartes is outlined in paragraph concern is to find an initial basis, starting from which there is only the opportunity to build something lasting.
The method, which he uses the overthrow of his opinions (logical word choice, as all plays without sound basis only opinion character) is the universal doubt. This is characterized by two criteria (AT VII, 18): All that I can not doubt, and certainly is more reasonable, to discard. II Everything is built on something that has to be rejected by criterion I, is necessary to reject as well.
It is thus urgent to investigate not all individual...