1. Argument for Skepticism

The paradox for what we consider to be a dream state and for what we consider to be awake in the actual external world – reality – is expressed through the skeptical hypothesis. It is the idea that we cannot be certain that what knowledge we take for granted to be true is indeed true. We cannot even be certain that we are not dreaming.

For how do we tell whether we are? There is no test that we can give ourselves that cannot perhaps be concocted and believed in a dream state. The skeptical argument parallels the agnostic argument (pertaining to the existence of a god or gods) in the sense that both argue that we simply do not have the tools to lay claims to certain knowledge. It challenges the notion that we have any knowledge at all.

The skeptical argument stems from the principle that everything we take to know is based upon our senses. The skeptical worry ripens when we realize that the senses are sometimes deceptive. Again: there is no test that we can give ourselves that could help us distinguish illusory dreaming from reality because we know that generally, our senses do not alert us to the fact that we are dreaming. Every state we are in is dependent upon our senses. Anything we have accepted as true through our senses may perhaps be fraudulent. Therefore, it is quite possible that I am dreaming, or that my brain is in a vat currently connected to a supercomputer which provides it with electrical impulses that my brain would normally receive were it connected within an
actual human body experiencing the real world. Another possible situation would be that I am an insane person in an asylum tied to a bed who is having experiences of student working on an assignment.

Simply put, if I cannot distinguish whether I am dreaming, than I cannot know whether most of my beliefs are completely false. If it is impossible to rule that I am dreaming, I do not have ample grounding and merit for believing any of the things which I take for granted to believe. Again, I do not know these beliefs.

Some may argue that the skeptical hypothesis is less plausible than the real world hypothesis. They point out that the real world hypothesis has more merit because, as far as we can tell, this “real world” is what we have experienced; for the most part, our experience has not yet led us to believe that we may perhaps merely be dreaming our experiences. Sufficient proof needs to be given to support the skeptical hypothesis before it can override the incumbent real world hypothesis that most ordinary people follow.

However, take for example the former widely held belief that the world is flat. No one had any reason to doubt this belief until the Greeks began to discuss the earth and its shape around the 4th century BC. Not many people had, at that time, traveled out across the ocean – and perhaps many who did never returned. Discounting mountains and valleys, the earth definitely did look flat. There was no evidence to suggest the contrary.

If we go by the structure of thought put forth by those who currently disagree with the skeptical hypothesis in this way: the people who lived before the 4th century BC had more reason to believe that the world was flat. Based upon the evidence they had, the world seemed flat, and therefore it was more plausible than the idea that the world is round. Therefore, according to their train of thought, the world is flat.

Of course, if no one had ever questioned the belief that the world was flat and sought to find out whether it was, no one would have ever found the evidence showing that the world is actually round. In this sense, it could be reasoned that skeptics plead ignorance to true knowledge of this world; they pose the question regarding the validity of what they take to be knowledge, and therefore then seek to find evidence of genuine knowledge.

2. Bouwsma’s Response to the Skeptic

Picture the following scenario: you wake up in the morning. Your day begins exactly as it had the day before. You look out the window, you see the newspaper boy. He waves at you, and as usual, you wave back. There is nothing noticeably different about your life. However, you are dead. Indeed, you do not notice that you are dead. This is because you were killed by an Evil Demon. In this scenario, everyone who is killed by the Evil Demon is doomed to have illusory experiences of the rest of their lives – for the rest of their pseudo-lives – as if they actually are alive. Does it make a difference that
what you are experiencing and think to be true – that you are alive – is not true?

Though your current experiences are entirely illusory, had you not died the previous night, you would have exactly the same experiences, so we conclude that it does not.

Bouwsma makes the distinction between thin illusions and thick illusions. A thin illusion is something that resembles something else just well enough to deceive. This means although the deception is good, it can be detected. An example of this type of illusion would be a very well made prosthetic hand that moves and operates just like a real hand. However, upon inspection, one can feel for the difference in texture of the prosthetic hand versus the texture of a genuine hand.

The illusory experiences of your daily life as a dead person would be examples of many thick illusions. A thick illusion is something that resembles something else so thoroughly that it cannot be detected as an illusion, even in principle. Unless the Evil Demon decides to tweak with your life in such a way to get you realize you are not alive, you would otherwise never notice that you are dead. The illusory fried eggs you eat in the morning as a dead person resemble exactly the same fried eggs you ate when you
were alive – the exact fried eggs you would be eating if you were alive. Therefore the illusory fried eggs are the same as genuine fried eggs.
Of course, the skeptic would deny this claim stating that the illusory fried eggs are indeed illusory; you are victim of the deception concocted by the Evil Demon. Bouwsma however, would reply that you, the dead person, would define your illusory fried eggs as
real. It makes no difference to you because you will never experience genuine fried eggs again. Additionally, the illusory fried eggs do not differ to your senses from the genuine fried eggs you experienced with the senses you had from when you were alive.

Essentially, now you are not allowed to experience anything else that people who are alive would deem a real experience. Though live people are not experiencing any of your illusory experiences, the only experiences you have are these illusions set forth by the Evil Demon. Your illusory experiences comprise what you define as your reality.

Everything you experience, though creations of the Evil Demon, is what is real to you: from the illusory newsboy, the illusory coffee, the illusory fried eggs, and finally, your illusory self. It is pointless to take into consideration the genuine world when you cannot tell the difference. Everything seems exactly as it was before when you were alive with the exception that everything is now an illusory creation of the Evil Demon. According
to Bouwsma no illusion exists where it is impossible to use the senses to detect an illusion.

In the situation in which I am an insane person strapped to a bed having experiences of being a college student working on an assignment, since it is impossible for me to use my senses to justify that I am not a college student working on an assignment, what I am experiencing is not an illusion.
We can only be deceived if it is possible for us to detect the illusion. Again, thin illusions are what Bouwsma considers to be detectable. Bouwsma would agree that if, in your dead state, you realized that when you waved at the newsboy you realized your hand was transparent, you had indeed overcame an illusion. Of course, it would be required that you remember what the state of your hand was before, when you were alive, how it contrasts with your current transparent hand, and that you are able to tell the difference
between the transparent and your former opaque, fleshy hand. However, it is important to point out that it is only in these scenarios in which it is possible for us to detect the illusions does Bouwsma agree actually are illusions.

3. Moore’s Response to the Skeptic

Moore believes that he can prove that the external world exists if he can prove that external objects exist. Proving that such things as lamps and picture frames exist would be what is required to prove that external objects exist. Finally, if it can be shown that external objects exist, we can perhaps rule out that we are currently dreaming. He defines external objects as objects that exist independent of our minds. For example, we take dogs to exist independent, or outside, of our minds.

Additionally, Moore does not think that we need to prove that there are external objectsto know that there are external objects. He introduces the idea that it is simply more reasonable to believe that there are external objects to our minds.

Moore concedes that we cannot prove whether or not we are dreaming. However, it is not necessary that we distinguish the existence of our hands from the hands in a dream in order to know that our hands are real external objects. The incumbent knowledge that we have hands supercedes the skeptic’s challenge that we do not know that we have hands. Since he believes he has proven that our hands exist, it means that external objects exist.

He demonstrates his proof, with his hands, with which premises he readily admits that he does not care to fulfill resulting in the proof becoming obviously circular. However, the point he makes is that we do not know anything else better than that we have knowledge of our hands. It seems Moore would use this same reasoning to justify the existence of any other external objects such as trees, books, and paper. He disagrees with Kant on the idea that the acknowledgement of the existence of external things has to rely on faith if we cannot provide adequate “proofs” for their existence. It is ultimately through this structure of thought that it can be said that Moore argues against the skeptical hypothesis. Again: we can know things which we cannot prove.

Moore addresses Russell’s concern that the only way we would be able to reject hypothesis that we are perpetually dreaming would be to rely on inductive arguments.

Russell would say it is because we do not know immediately that we are not dreaming, and secondly, that it does not follow logically from anything we do know immediately.

Russell states then that we cannot say that we are certain that we are not dreaming – merely, that we are probably not dreaming. Moore would agree with Russell in the sense that it is true that we do have to rely on inductive reasoning to justify that we are not dreaming – that it is possible that we may be in error. However, according to Moore’s reasoning, we should conclude that though we may arrive at a belief inductively, we may be certain that the belief is true.

Moore even goes so far as to assert that it is more reasonable, ironically, for us to truly believe in the existence of an object, such as a couch, than for us to believe that any one of Russell’s four assumptions are true. The four assumptions are abstract ideas of which we are not immediately certain. These abstract believes also do not follow logically from anything we do know immediately. Indeed, it would not be wise for us to base whether or not an object exists external to ourselves if our criteria for judging whether or not it is a real external object are uncertain principles.

Moore most likely would also declare that it is more reasonable for us to believe that we are not dreaming, than for us to believe that the skeptical hypothesis is true; we do not feel as confident about our knowledge of the skeptical hypothesis as we do about the knowledge that we are not merely dreaming.

Skepticism [pdf]