The Dream Argument and Skepticism
When it comes to the argument from the dream, Descartes works on a project to determine what might be called the scope or extent of what our knowledge is supposed to be in relation to what we think we have. Here Descartes resorts to a skeptical argument as a valid resource, and in this sense he is working in the field of methodology, with the aim of establishing what he considered true knowledge.
From an epistemological point of view, this argument reveals problems regarding our knowledge of the external world and how to base all our knowledge. The central problem of the dream argument is to establish a reliable substrate to refer to sensible knowledge, by virtue, as Descartes says, that our senses frequently deceive us. Therefore, this argument from the dream refers to the lack of a reliable criterion to establish our knowledge of the outside world. Thus, if dream thinking is equivalent to waking thought, it becomes impossible to distinguish between the two, thus reaching an unaffordable situation to establish a reasonable criterion that allows us to refer to the outside world.
Due to this equivalence that leads us to doubt, and that knowledge occurs only awake, Descartes raises his argument. With a very peculiar concept of doubt, which is still a knowledge of something, of the lack of reasons to believe, as is the case, Descartes achieves his project. This is the starting point that Descartes wants to reach, since his purpose is based on a methodological resource that becomes the starting point to reach knowledge, the Cartesian I know nothing is a I know something.
Here we can rely on formal logic and speak as follows: the proposition I cannot know because I am not awake implies that I cannot know unless I am awake. Being awake is a necessary, but not sufficient, condition for knowing.
Descartes presents in his first meditation the skeptical argument of the dream, which he especially interests us because he introduces us to Cartesian epistemology.
Therefore, Descartes behaves like a skeptic to respond to skeptical arguments. It seems to tell us that for a skeptical argument, another more skeptical argument. Descartes warns us of credible knowledge as a point of support for the contemplation of truth.
In this argument Descartes tries to establish a safe line of demarcation that allows us to know if we are dreaming or we are awake. He establishes criteria that satisfy waking thinking, but not dream thoughts.
Although there is certainly a transition between dream thinking and waking thinking, any discourse about a continuity from the first to the second is apparently a mistake. This, by virtue of the fact that not knowing if one is asleep or awake implies an impossibility of our knowledge of the external world and, of course, the possibility of knowing it. And since for Descartes the criterion of truth is based on evidence, and this must comply with the attributes of clarity and distinction, understood by Descartes as a criterion to use to decide what to believe, said criterion vanishes when not being able to establish a Line demarcation that breaks the continuity between the two types of thought mentioned.
If so, this would lead us to a highly necessary dichotomy that allows the criterion of evidence, and with it, to be able to know if one is asleep or awake at a certain moment; This would allow us to eliminate self-doubt and with it all falsehood; because if I can determine if I am awake, I can determine that I can know. And, from now on, I will be able to exercise my faculty of will and with it that of judging; but always considering sufficient reasons.