Skip to content

Can’t prove you’re not dreaming?

October 17, 2011

When the subject comes up of being able to prove something, one frequently hears the claim that a person can’t prove he or she isn’t dreaming. This response is given to show that proof isn’t always required to justifiably believe something is true.

But I wonder, why can’t one prove one isn’t dreaming?

Of course, if one has in mind Cartesian proof, then, no, I suppose it can’t be proved. But most of what we justifiably believe isn’t known this way. One needn’t fall back on the dreaming illustration to defend believing something without this kind of proof. Who cares if it cannot be proved? This is no more than a trivial parlor game.

Still, can a good case be made for believing justifiably that one isn’t dreaming? I think it can. Let me give it a try.

I have the experience of going to bed for the purpose of sleeping. Before the alarm clock awakens me in the morning (for the moment using the typical language for this experience), I have what I call a dream. (The dream itself isn’t a shared experience with others, but we all know what we mean by having a dream because the circumstances of experiencing them and the descriptions of them are so similar.) My dreams are typically disjointed, although they can on occasion stay on course for what seems like a long time. More often, though, they jump about and include some rather bizarre elements.

These dreams are markedly different in nature than what I experience while “awake.” When, in a class on epistemology, the professor made the claim that we couldn’t prove we weren’t dreaming, I reflected on what my experience in that class and previous classes was like. I recalled getting in my car at my office and driving to school. I had done this many times (three times a week). If I had time after arriving on campus, I might go to the coffee shop for a fill-up before class; if not, I went straight to the classroom. I sometimes passed people I knew and greeted them. If it was raining, I put up my umbrella. There was never anything disjointed or bizarre about these experiences. I didn’t get in the car at my office and suddenly find myself in the college parking lot without driving. I never met a friend along the way who told me he’d been elected president of the United States. I never found myself, without explanation, suddenly running through a big house from door to door, looking for someone. My wife didn’t appear, holding someone else’s dog, to tell me our son had joined the army.

These are the kinds of things that happen in dreams (at least in my dreams!), but they never occur in a waking state in such erratic and disjointed ways. Of course, very odd things do happen in life that leave people saying it’s like they’re in a dream. However, the fact that they say this shows an understanding of the difference between dreams and waking life. Sometimes I dream about very normal things, but then I wake up and the dream is gone. I never have the experience, in a waking state, of being in a familiar location away from home, talking to someone who doesn’t live in my house, and then suddenly finding myself in bed in my home next to my wife with an alarm clock ringing. There is a significant difference between the dreaming state and the waking state.

So when the professor says I can’t prove I’m not dreaming at that moment, I can simply reflect on the previous hour or two to be quite satisfied that what I had experienced is very different than what I experience while asleep and know, based upon good evidence, that I am not dreaming. Of course, if all I am allowed to consider as evidence is what is happening at the very moment he presents the challenge, then he’s right. I’ve dreamt about hearing lectures before. But if I am allowed to broaden the time frame, then I can know I’m awake.

Someone might want to make the bigger claim that one is always dreaming. If that’s the case, then I also have the experience of having dreams within a larger dream when I enter the state of what I think of as sleep. Because the sleep-dreaming experience is quite different from the awake-dreaming one, I am quite justified in believing that these are two different kinds of states even if the latter one isn’t genuinely a waking state. The word “dream” does not have the same meaning in both. A different word should be used. Why not call the bigger dream “being awake”?

But someone might object that to call that state “being awake” implies that one is then experiencing an external world, that the people and schools and professors and such are not figments of my dreaming imagination, and, further, that this has to be proved. If one truly is asleep at that time, then one has no way to know if anyone else truly exists. However, unless one wants to defend epistemological solipsism (or go further and defend metaphysical solipsism), then one should go with the more reasonable explanation. The burden is on the solipsist.


From → Bad arguments

Leave a Comment

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: