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 ever tell whether or not he is dreaming. How can he know he perceives his hands right now? Maybe, it is all just a dream. If it were just a dream everything would seem to be the same.
In order to have knowledge the suggestion he is dreaming is false, he somehow has to have some knowledge of being awake. I believe his dream argument could be formed in this way: 1. When we are dreaming we are not in a good position to tell whether we are actually dreaming or awake. 2.
Any experience you are having right now could also mean you are dreaming. In other words, you can’t possibly know you are dreaming even if it is a dream.
3a. For each of your experiences, you can’t tell whether your experience is a dream or not. (You can’t tell which of your dreams is a waking experience or a dreaming experience). 3b. For all you know, all of your experiences may be dreams. (You may be walking around in a dream, never having any walking experiences) Most philosophers think the dream argument supports both conclusions, but many philosophers also think this argument is strong enough to support 3a but not 3b.
It is not really clear whether Descartes is arguing for the stronger claim or the weaker claim. It could be 3b, the weaker claim, is enough to support his purpose. Maybe he does not need a stronger claim to prove his theory. 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:
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 declare he is dreaming, it will not work. So there goes the premise of the argument.
The most Descartes can say in his argument is “you can’t tell whether you experience is a dream,” premise two states “You can’t possibly know you are dreaming,” to premise 3, “you can’t tell if you are dreaming” to the conclusion, “You can’t know anything. ” In order for Modus Ponens to work once again Descartes would have to know he was dreaming. As stated above he cannot state his position as if he is dreaming, so there goes the premises argument. So if this is not a valid argument, then perhaps there is a way to revise my interpretation on Descartes’ Dream argument so it turns out to be a valid rgument. Can we make the argument valid by changing premise 4? 2. Any experience you are having right now could also mean that you are dreaming. In other words, you can’t possibly know that you are dreaming even if it really is a dream. 4. I know that I am dreaming.
Therefore, you can’t know anything about the external world based on your sensory experiences. This is now valid but is Descartes actually dreaming? Lets try switching around premises one. 1. If I cannot distinguish with certainty between sense perceptions and dreams, then I cannot believe anything based on images as true. . I cannot distinguish with certainty between sense perceptions and dreams. 3. Therefore, I cannot believe as true anything based on images. The argument is now valid again. But the question remains, whether the argument is sound and all the premises are true. A dream is a dream because its external conditions make it a dream and not because of a sense perception. If I am asleep and having an image of a body, than I am dreaming. If I am awake and having an image of a body, then I am not dreaming. Usually I am having a sense perception, but it could also be a hallucination.
Dreaming is a certain kind of state. The only way to know you are not dreaming is to know you are not in a state of being asleep and having mental images, sounds, etc. No amount of images, sounds, can tell me I am in the state of being asleep and having images, sounds, etc. before my mind. If premise 2 is true, you can never be certain you are dreaming, as opposed to having sense perception. For instance, I can never step outside of myself to check what state I am in. It is indeed possible I could be dreaming. Descartes, however, has a very different kind of reply to the dream argument.
He does not challenge premise 2 at all, instead he challenges premise one: If I cannot distinguish with certainty between sense perceptions and dreams, then I cannot believe as true anything based on images, etc. Descartes states in meditation one, “Nevertheless, it surely must be admitted that the things seen during slumber are, as it were, like plain images, which could only have been produced in the likeness of true things, and these general things —eyes, hands, head, and the whole body,–are not imaginary things, but are true and exist. This statement is actually very clear because the reply is the contents of dreams (Mt.
Everest, other people, houses, etc) must come from reality. We get images through the world that we live in, so even if I am dreaming, I know there are mountains, people, and houses. They must exist in order to have dreams like the ones I have. If the world was different then I would have different kinds of dreams. ” In Descartes final thoughts he admits it seems to be possible I am now dreaming even though no one could know anything about the world around us. I think Descartes point to be made throughout the dream argument is we are able we are not dreaming if we are to know an external world around us.
If we are to know our external world around us, then we would have a better understanding of why we dream. It would also give us a better understand to distinguish from being awake to dreaming. It seems to me the point throughout his dream argument the point he is trying to make is we cannot be sure of what we experience as being real in the world is actually real. Descartes may have not made his point to be valid or true, but made us think outside the box, there are other possible choices to why we experience these thoughts when we dream.