Near the beginning of this course, we discussed Descartes’ dream argument in which he states one can know that P only if one knows that he is not dreaming P. And because one cannot know that he is not dreaming, one cannot know that P. This argument sparked my imagination and I tried to think of all the ways I could prove whether I am dreaming or not.

Although I have had some fairly vivid dreams, I feel that I have some intuitive sense that clues me in to the fact that my daily life, including this very moment, is not a dream. But how am I justified in saying this? First of all, I think the fact that I can reflect back on past experiences and know that they were dreams indicates that I have some point of reference to compare them to. In fact, all my dreams have in common the fact that I refer to each one of them from the same conscious state, that is, what I like to call reality. My reality encompasses all my dreams within itself. There is never a time in which I can refer to my reality from an outside space. There is no point of reference outside of the Now, as far as I know.

Descartes’ argument suggests that because one’s senses can be “fooled” in a dream, they are not trustworthy. I do not think this follows because it assumes dreams have powers which they do not. Dreams cannot cross over the boundary of consciousness and “fool” our senses in reality. Because I dreamt I saw a dog, it does not mean that when I see a dog there is a chance it is generated by a dream.

Now I realize that this is not exactly what Descartes had in mind. His argument deals with our perception as a whole, whether or not our experience in the Now, all senses considered, is a dream. The argument does not consider isolating a particular collection of sense data and saying it might be a dream while everything else is real. But this leads me to an important point which I think the argument does not take into account.

Perceptions are never fooled in dreams. Dreams have their own rules when it comes to perception. I have had dreams in which I did not have a sense of smell or touch. My senses are not being fooled into perceiving the absence of smell and touch; they simply do not exist in the context of the dream.

In reality, sensations work from the outside in, filtered through our senses to our brain where they are perceived. Dreams begin on the inside, pre-emting the usual process of perception. There is no reason to believe that dream experiences should behave in the same way as “real” experiences especially since they are received in a way very unlike real experiences.

For all intents and purposes, our dream senses work perfectly. In fact, one could argue that they are more accurate than real senses. In a dream, if one is appeared to by a dream cat, then it actually is a dream cat. Because of the nature of dreams, taking something to be a cat guarantees that it is a cat. Objects that exist in the same “dimension” or space where the act of taking occurs cannot be anything other than what they are. One might argue that there are dreams in which one seems to perceive a certain object, but upon a closer look finds that it is not that object at all. A basket of severed heads turns out to be a bowl of fruit. I would say that both takings are correct: at first there is a basket of heads which had always been a basket of heads, but then there was a bowl of fruit which had always been a bowl of fruit. That is just the way that particular dream happened to work and it is not restrained by the same rules as reality. They are two separate realms.

So I think it is unfair to allow the goings-on in one realm determine the accuracy of one’s senses in the other. This works fine when the two realms are kept so distinct. But what about hallucinations? How do they fit in to this picture?

I happen to have experimented with LSD and can use my experience to discuss hallucinations as I have done so with dreams. Unlike dreams, hallucinations occur while one is still aware of a normal reality. It is more accurate to say that hallucinations “fool the senses” than to say that dreams do, because the chemical workings of LSD tamper with one’s actual physical senses as well as one’s mental perceptions. Under the influence of the drug, my senses were sharpened and made more acute. But my senses did not always work together like they usually do. For instance, there were times when I felt that my fingers had fallen off, but upon looking at my hand, I saw that this was not the case. I would see a person or creature, but I would not hear the sounds that ought to accompany the thing I was seeing because the person or creature did not exist.

Hallucinations are a middle ground between dreams and reality, a translucent scrim against the backdrop of the external world. Because LSD has access to the physical senses, it has deceptive powers which dreams do not. Like dreams, LSD can reverse the process of perception and work from the inside out. If I take something to be a giant lung, the drug communicates this to my senses and makes my senses cooperate to the best of their ability. What I am actually looking at is a tree, but I have decided to take it to be a giant lung so my senses do all they can to agree with my mind. I’ll admit that I can be fooled about what I am perceiving while on LSD, but I can still return to that space of reflection and determine that I had indeed been fooled. My senses eventually revert to a normal state and I no longer experience the effects of the drug. With one exception. While “tripping”, I saw incandescent lines, like neon thread, connecting the stars, forming constellations. I still see them even though I am not using the drug. I have formulated several theories to explain why this might be happening. I may have suffered permanent damage to my sensorium which causes me to always have the hallucinations. My mind may just associate the stars so strongly to my experience with the drug that it just “fills in” the lines. Or the drug may have tapped some new level of perception in my mind and I see lines between the stars because they are really there. The latter is the most intriguing and is the sort of idea that would persuade me to take LSD in the first place.

So basically, what I am trying to say is that because we are able to reflect upon such experiences as dreams and hallucinations from a point of lucidity, we can place those experiences in a realm separate from common reality. Even though the other realm appears, on the surface, rather like reality, it has unique mechanics which operate under very different rules. There is no good reason to think that because a sense was apparently deceived in a dream that it should no longer be trusted. One may as well say that when one is blindfolded and sees nothing, the sense of sight should no longer be trusted because of a situation in which sight did not provide accurate information about the surrounding world. This makes no sense because we know that sight is working just fine under those conditions. We must always give our ability to reason access to our perceptions rather than creating an artificial scenario where our perception is left on its own.