Introduction
In ”The Significance of Philosophical Skepticism” Barry Stroud writes: “If, in order to know something, we must rule out a possibility which is known to be incompatible with our knowing it, Descartes is perfectly right to insist that he must know that he is not dreaming if he is to know that he is sitting by the fire with a piece of paper in his hand.” (Stroud, 1984 p. 30). I call this “sentence A”. In this paper I will first explain what sentence A implies, then I will explain how he justifies this conclusion and last I will present the options he gives for refuting Descartes dream argument.
What Strouds sentence implies
Knowledge is in a special relationship to truth. If I claim to know something, then that which I know will have to be true in order for me to know it. If it turns out that what I thought I knew where in fact false, then it means that I never really knew it at all. I have to know the truth of my knowledge in order for it to count as knowledge. We might say that this is a very strong condition for truth, but if we accept it then Stroud agree with Descartes that we must rule out the possibility that we are dreaming in order to know anything about the external world
Maybe there is a looser everyday meaning of knowledge, which allow that we know things based on having a clear perception of it, and even if our senses deceive us at times, we usually trust that they give us true information about reality (Stroud, 1984 p. 9).
Descartes challenged our most fundamental beliefs about knowledge by claiming that we can never really trust our senses to give us access to truth. He said that for all we know we might be dreaming right now, and what we think is a clear perception of something real might be just a dream (Ibid, p. 12). This means that it is always possible that our experience is not in direct contact with the external world. Descartes claimed that in order for us to know anything about the external world, we must be able to prove that we are not dreaming (Ibid, p. 13).
What Straud wants to make clear in sentence A is that in order to know something, we must be able to rule out any possibility that our knowledge is not true This means that we must know that the strict conditions for truth that Descartes finds are fulfilled in order to know something. Then it seems to be impossible for us to prove that there is an external world based on sense perception even though it is very possible for it to be real (Ibid, p. 30).
How Stroud justifies this conclusion
Stroud argues that the strict conditions for truth can never be fulfilled if we insist that it must be fulfilled in order for us to have knowledge of the outside world, because fulfilling it would require knowledge which itself would be possible only if the conditions were fulfilled (Ibid, p. 30). It is impossible to find a test for not dreaming that we can know have been successfully preformed because we might have just dreamed that we preformed the test. This means that we can never fulfill Descartes conditions for knowing something about the world, it is simply impossible to know that we are not dreaming according to Stroud (Ibid, p. 23).
Strouds options for resisting Descartes dream argument
For Straud we only have two options for resisting the dream argument. Our first option is to reject Descartes strict conditions of knowledge, which implies that we never know anything at all about the external world, even if we do happen to be right. Alternatively, we can try to prove that we can in fact know that we are not dreaming (Stroud, 1984, p. 20).
One option for resisting Descartes dream argument is by saying that it is possible for me to have knowledge about the world even if I dream because I could dream something that actually turned out to be true. If for example I dream that a dog is barking and I wake up and it turns out that there is in fact a dog barking. Would I not know even in my dream that the dog is barking? (Stroud, 1984, p. 16).
According to Stroud I have no knowledge about a barking dog in this example because even if a real dog is causing me to dream about a dog barking, I still do not know what is happening in the world around me when I dream. It is just a coincidence that my dream happened to be true and therefore I cannot be said to have any certain knowledge about the world around me even if it is possible to dream something true (Ibid p. 17). All general knowledge about the world disappears because it is based on the senses and we can never prove that they have a source in a reality outside the dream.
Another option is to deny Descartes claim that we can never know that we are dreaming. Then we can admit that we must know that we are not dreaming in order to know anything about the external world and that we can prove that we are not dreaming. We simply accept Descartes conditions for knowledge and then we try to show that we can meet them (Ibid p. 20). Stroud claims that this is not possible because we have no way of distinguishing dream from wakefulness.
Conclution
In this paper I have explained that Strouds sentence A implies that we must rule out the possibility that we are dreaming in order to know anything about the external world and that this is impossible. He justifies this conclusion by saying that ruling out this possibility would require knowledge which itself would be possible only if we could rule out this possibility. I have also presented Strouds options for resisting Descartes dream argument by eighter rejecting his conditions for knowledge or trying to prove that we are not dreaming.
Sources
●Stroud, B. (1984) The Problem of the External World: The Significance of Philosophical Skepticism. Oxford U.P. ISBN 9780198247616. Chapter 1. DOI: 10.1093/0198247613.003.0001
You may be dreaming that I upvoted and commented on this interesting article! If my only existence is inside your dream, I hope it is a good dream and not a nightmare. Sweet dreams!
Thank you for this. Resteemed