Descartes's evil demon fools a poor brain into believing reality exists.

The Illusion of Certainty

The Illusion of Certainty.


What are you certain of? What do you definitely know? Is there anything immune to doubt?


You might be familiar with  the saying “I think therefore I am”. These are the words of Rene Descartes, and the focus of today's article.


Descartes came up with this pithy saying as a result of his investigations into dubitability: what is it impossible to doubt? His answer? Your own mind, and literally nothing else. 


Even the existence of an external reality isn’t certain for Descartes. “But how can that be?” I hear you shout. “We have sensations of an outside world! We see the sun. We  hear the birds, we feel the rain! I know the world exists, my senses tell me so!”


But then again, haven’t we all had dreams we’ve believed were real up until the very moment we woke up? And isn’t that proof that our brain doesn’t require the input of an outside world to conjure up the impression of one? 


It also seems that our waking senses do not report an objective reality back to us. You can test this yourself with a quick experiment. Put your left hand in ice water and your right hand in hot water and after thirty seconds, put them both into the same bowl of lukewarm water. Your left hand will tell you the water is warm, your right hand will tell you it is cold; different sensations, same stimulus. This seems to suggest that your senses aren’t simply reporting the world to you as it is(or perhaps that the question "what is the world?" Is more complicated than you might at first think). This, and the previous point about dreams, leaves room for some divine fuckery.


Suppose, as Descartes did, that there is an all-powerful demon whose goal it is to fool you. The demon simply presents the facade of an outside world, and because it is omnipotent, it does a damn good job of it, perfectly crafting the sensory experiences you would expect to have if the world did in fact exist. If this creature decided to fool you in such a way you would be utterly unable to tell(maybe it’s doing it right now!). 


Probably the most distressing part about this philosophy is the doubtability of the existence of other people. We only have a direct experience of our own consciousness, we infer the existence of everyone else’s through our sensory experiences of them. 


But this profound doubt is not all reaching, we have one bastion left for certainty. For an evil demon to fool you, you have to exist. The mere fact that you are experiencing something means that there is something capable of experiencing. 


I think, therefore I am.

This conclusion makes no claims about what you are beyond the fact that you are something that can think and experience.


Maybe you’re a brain in a vat hooked up to electrodes that shock you in all the right places so that you dream up the strange world we seem to inhabit. 

Perhaps you are one facet of some more supreme consciousness. Perhaps you are to it as our subconscious is to us, and you fade in and out of its focus.


Or perhaps all is as it appears to be, and you live in a world populated by observing, thinking creatures much like yourself, trying to make sense of a world that was not set up to be easily understood.


People are often quite unsettled by thought experiments like this. I think it’s important to keep in mind that just because something is technically possible doesn’t mean it is at all likely. 

I think the evil demon thought experiment is best treated as an exercise in humility and humanity. Are you treating the people around you as though they may have something useful to communicate? Are you prepared to receive it? Or are you too attached to your view of the world to accept any alterations? Are there people whose points of view you dismiss as worthless or unimportant to you before you give them a chance? Why? You don't even know if the world is real and you think you know all the important things about it. The very reason we evolved language was because those people who could collaborate outcompeted those people who couldn't. The superiority of shared perspectives is not just an ego management tool, it's a force of evolution, and one of humanity's most fundamental tools. You handicap yourself for no reason when you assume others have nothing to offer.Is it really fair to assume that the tools you inherited when you came into this world are the only ones worth having?

Here is another thought experiment. Imagine that everyone in the world has only your skillset, and observe how quickly society falls apart. The cool thing about this one is that the outcome is the same no matter who you are. Einstein still needed his food to be grown and his house plumbed.


The fact that we can’t be certain about many things means that faith in some things is necessary to living a decent life even if you are irreligious. What I mean is that we need to behave as though some things are true despite the fact that we can’t know for sure that they are. We need to have faith that the way we treat people matters, despite the fact that it’s possible that they are an illusion. Or put even more broadly, we need to have faith that our actions have an effect on the way the world is, and that the way the world is matters, because if we don't, we end up making it worse by accident.  


I will have to come back to the topic of this sort of faith. It's a whole can of worms in and of itself, and I'd hate to do such an interesting idea a disservice by trying to cram it into the backend of this piece.


Thank you for reading my friends.


By James Rowarth


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Hi, I like Science, Philosophy, Art, Music, Boogieing hard, and writing. I have a BSc in biology, microbiology, and philosophy, making me super smart. If that sounds interesting, why not check out my blog "A Grand Map" It's really cool, I would know.

A Grand Map: Finding Our Way
A Grand Map: Finding Our Way

If you like science and philosophy, well gosh darn, I think we might be able to help each other out. I like to make complex ideas simple. I also like hard questions. "How should we live?" "What can we be certain about?" "Why did we evolve emotions?" Any question I find interesting has a chance of being written about here. Why should you bother spending time reading what I have to say? I'm incredibly interesting, funny, talented, super sexy, and most importantly, mega humble. Enjoy my words!

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