Essay on Descartes Dream Argument - Philosophy

1406 Words Oct 28th, 2008 6 Pages
How do we know we are not dreaming some particular experience we are having, or we are not dreaming all our experience of this world? When we dream we imagine things happening often with the same sense of reality as we do when we are awake. In Descartes dream argument, he states there are no reliable signs distinguishing sleeping from waking. In his dream argument, he is not saying we are merely dreaming all of what we experience, nor, is he saying we can distinguish dreaming from being awake. I think his point is we cannot be for sure what we experience as being real in this world is actually real. When Descartes remembers occasions when he is dreaming, he falsely believes he is awake. Reflecting on this, Descartes thinks he cannot …show more content…
The last step in Descartes argument says if he cannot tell whether he is dreaming, then how can he trust any of his senses telling him about the environment? To know anything about the external world on the basis of his sensory experiences, it seems like
Descartes would have to know those experiences are not all just a dream:
4. To know anything about the external world on the basis or your sensory experiences, you have to know that you are not dreaming.
I believe the things in my dreams must have been patterned after real things. So, even if I might be dreaming now, I know the world has colors, things that take up space, have shape, quantity, and a place in space and time. Now if you pull premises 1-4 together, we get the result of the conclusion:
5. Therefore, you can’t know anything about the external world based on your sensory experiences. In an interpretation of Descartes Dream Argument, premise 1 supports premise two and premise 3a and 3b support premise 4. So let us take a look at premise 2, 4, and the conclusion. This looks like the valid inference rule, such as modus ponens.
P  Q
P__________
Therefore, Q

However, that is not what is exactly happening in the dream argument. For premise 4 says to know you would have to know you are not dreaming. But premise 3 says you cannot know you are dreaming. In order for Modus Ponens argument to work, it would have to contain the premise: “I know I am dreaming.” Since Descartes cannot actually
Open Document