Escaping the vat: a fantastical adventure with Descartes, Hume, and Kant

Dr. Ghassan Dabbour

Head of Planning & Projects


If you don’t know, The Matrix was a blockbuster film trilogy released between 1999 and 2003. It tells the story of a software engineer who realises that he is actually living inside a simulation. Among philosophers, this scenario is widely explored in a thought experiment called the ‘Brain in a Vat’ (BIV). It is fundamentally concerned with whether we can ever achieve certain and indubitable knowledge about something, and the epistemological methods by which this can be made possible. The BIV experiment comes in many adaptations, but it basically goes something like this: a highly advanced alien race abducts you and suspends your brain inside a vat which contains life sustaining fluids. Your brain is then connected to wires which fire neurochemical signals that emulate sight, smell, touch, taste, and sound. A whole reality is then generated giving you a simulated but perfectly normal conscious experience.



Given that everything your senses grasp is entirely experienced inside your mind and never outside of it, who’s to say that you are not a brain in a vat right now? And how can you escape it if you are? In the spirit of this, I am going to narrate a short fictional account of how three philosophers came to terms with the BIV rather than dryly explain their ideas with facts and figures. Although the stories are invented, the philosophical concepts explored and the terminologies used – however fanciful – are very real!



One: Descartes’s demon, 1637

In front of the fireplace, a demon had suddenly appeared sitting opposite René Descartes in his armchair, a wicked grin drawn across its face. Descartes had always suspected that the whole world around him may be no more than an illusion; a masterful deception conjured by a cunning evil. Now that this evil had shown itself, Descartes’s suspicions grew ever larger. The demon wouldn’t speak, but its mischievous glare challenged Descartes to determine once and for all if it was playing tricks on his mind or the world around him was indeed real. Descartes silently accepted the challenge. He started by doubting everything he intuitively took to be certain. The air he breathed, the colours he saw, the sounds he heard, the objects around him, the people, the places, the planet, the universe… all were false, all were apparitions. Even himself. He was not real. His body was not real, his mind was not real, his thoughts were not real, and his doubts were not real…. But wouldn’t that be impossible? How could he doubt that he was doubting when he needed doubt to doubt that he was doubting? “I cannot doubt that I am doubting. For in doubting that I am doubting, I am still doubting. And to doubt is to think. And to think is to exist. And to exist is to be real. I think therefore I am!” cried Descartes. He had just used reason to demonstrate the fact that he was real. He realised then that by using reason he could also prove that the world around him was real as well. It was with sound rational thought and not with fallible sense experience that Descartes confirmed the reality of the world and his own being. And just like it had suddenly appeared, the demon was gone. Descartes was victorious.



Two: Hume’s fork, 1739

Friends and strangers alike enjoyed the company of David Hume. With a happy-go-lucky attitude and a humorous sense of skepticism, Hume was the town’s most likable person. Hume, however, had not been himself lately. His cheer had transformed to gloom, his humour turned to anxiety, and his company become distant and unpleasant. Nobody knew, but Hume’s source of misery was a secret project he had been working on. A project so sinister, he dared not discuss it with anyone yet. You see, Hume, mad with curiosity, was actually attempting to summon Descartes’s demon back. And today he had finally completed fabricating the philosophical artefact that he needed to do so. He called it the ‘Fork’. It was a large bident: a spear with two prongs, with one prong embodying Ideas, and the other embodying Facts. Hume struck the bident on the ground twice and called for the demon to reveal itself. Out of thin air, Descartes’s demon then materialised, the same wicked grin still across its face. Hume pointed the fork at the demon and energised its power. The demon struggled at first, but it eventually submitted to Hume’s fork. Silently, and with a mischievous vindictive glare, the demon confessed that it had actually deluded Descartes into believing that reason had emancipated him, when in fact the causal mechanism of reason itself had been created by the demon. Just like sense experience can be emulated in the mind, reason can be planted and presented as if it is a real thought process. Descartes never escaped; he was only fooled into believing he did. Upon fully apprehending the genius of the demon’s trick, Hume’s face filled with excitement. He had so much to tell his friends about this great discovery; dark as it may be. He left the demon to itself and hurried along to his favourite social gathering spot, his fork swinging in his hands.



Three: Kant’s left hand, 1781

Immanuel Kant was stunned when he heard of Hume’s tale. For so long, Kant believed in the absolute power of reason and held it to be the purest form of knowing. Now that Hume’s fork had uncovered the fallibility of reason, he knew that he had no other choice but to summon back Descartes’s demon. He had to face it himself. Maybe he would be able to discern something Descartes and Hume had missed. Kant locked the door behind him, shut the window blinds, and sat back in silent contemplation. He closed his eyes and wandered around his mind searching for Descartes’s demon. He searched long and hard, but it was nowhere to be found. Frustrated, he held out his left hand in the void of his mind commanding the demon to reveal itself. But there was still nothing. Nothing but his left hand and the void. There, his left hand floated aimlessly in the vastness of an empty nothingness. It was then that Kant suddenly realised the answer to his problem. In an empty universe, a floating hand can neither be a left nor a right hand. It is just a hand. It is the presence of a knowing mind that gives a hand its directional property.  Paradoxically then, the only way to escape the vat is to escape your own mind, leaving behind your very ability to know whether you escaped or not. Basically put, if you want to know the truth about the reality of the world, you have to sacrifice your ability to know about the reality of the world. Kant was suddenly pulled away from his thoughts by an alarming sense of a malignant presence. He quickly opened up his eyes and saw that Descartes’s demon was now standing in the shadow of a corner menacingly watching him think. “The BIV problem is a category error,” Kant said to it. “There is no correct answer because the question is wrong.” For the first time ever the demon then spoke, “Yes. The deception is that there is no deception.”



Epilogue: Complete knowledge, 2020

Suppose you decide to sacrifice knowing for the sake of escaping the vat. “Wait!” I would warn you. Before you go consider this: what if you lose your ability to know outside the vat because there’s nothing left to know? After all, what use would be knowledge in a dimension where knowledge is complete? It’s true, you may finally achieve the complete knowledge of things-in-themselves (noumena) rather than the partial knowledge of things-as-experienced (phenomena), but you will lose that which made your quest to escape worthwhile in the first place: wonder! So stay here! Here, you can speculate about the phenomena of the vat – from multiple space and time dimensions, to invisibility, holograms, and impossible objects. Here, you can speculate about the phenomena of the mind – from intuition and intellect, to imagination, emotions, perceptions, and memory. It is the adventure on the road that matters, not the treasure at the end of it. I’m sure Descartes, Hume, and Kant would agree.



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