B R A I N I N A V A T
“'I think, therefore I am"
DESCARTES
DESCARTES
My particular favourite thought experiment is called the 'brain in a vat'. It is typical of its kind; violating as it does all known scientific laws and ethics. It has been profoundly influential; its concept permeates cognitive science, philosophy and popular culture. It is also very, very spooky.
The experiment asks you to imagine a mad scientist has taken your brain from your body and placed it in a vat of some kind of life sustaining fluid. Electrodes have been connected to your brain, and these are connected to a computer that generates images and sensations. Since all your information about the world is filtered through the brain, this computer would have the ability to simulate your everyday experience. If this were indeed possible, how could you ever truly prove that the world around you was real, and not just a simulation generated by a computer?
The idea for the experiment, which was popularized by Hilary Putnam, dates all the way back to the 17th century philosopher Rene Descartes. In his 'Meditations on the First Philosophy', Descartes questioned whether he could ever truly prove that all his sensations were really his own, and not just an illusion caused by an 'evil daemon'. Descartes accounted for this problem with his classic maxim 'cogito ergo sum' (I think therefore I am). Unfortunately, the brain in a vat experiment complicates this argument as a brain connected to electrodes could still think. The most important question posed, and which bridges these arguments, is what do we mean by 'am'? The 'brain in a vat' experiment has been widely discussed among philosophers, and many objections have been raised over its premise, but there is still no good rebuttal to its central question: how do you ever truly know what is real?
If you’re thinking this all sounds a bit like 'The Matrix', you’re right. That film, along with several other sci-fi stories and movies, was heavily influenced by the brain in a vat thought experiment. At its heart, the exercise asks you to question the nature of experience, and to consider what it really means to be human.
The experiment asks you to imagine a mad scientist has taken your brain from your body and placed it in a vat of some kind of life sustaining fluid. Electrodes have been connected to your brain, and these are connected to a computer that generates images and sensations. Since all your information about the world is filtered through the brain, this computer would have the ability to simulate your everyday experience. If this were indeed possible, how could you ever truly prove that the world around you was real, and not just a simulation generated by a computer?
The idea for the experiment, which was popularized by Hilary Putnam, dates all the way back to the 17th century philosopher Rene Descartes. In his 'Meditations on the First Philosophy', Descartes questioned whether he could ever truly prove that all his sensations were really his own, and not just an illusion caused by an 'evil daemon'. Descartes accounted for this problem with his classic maxim 'cogito ergo sum' (I think therefore I am). Unfortunately, the brain in a vat experiment complicates this argument as a brain connected to electrodes could still think. The most important question posed, and which bridges these arguments, is what do we mean by 'am'? The 'brain in a vat' experiment has been widely discussed among philosophers, and many objections have been raised over its premise, but there is still no good rebuttal to its central question: how do you ever truly know what is real?
If you’re thinking this all sounds a bit like 'The Matrix', you’re right. That film, along with several other sci-fi stories and movies, was heavily influenced by the brain in a vat thought experiment. At its heart, the exercise asks you to question the nature of experience, and to consider what it really means to be human.
"If real is what you can feel, smell, taste and see, then 'real' is simply electrical signals interpreted by your brain."
MORPHEUS - The Matrix 1999
MORPHEUS - The Matrix 1999
The Matrix film series present a version the brain in a vat scenario. The central character, Neo, begins the film thinking that he lives in a city, he thinks that he has hair, he thinks it is 1999, and he thinks that it is sunny outside. In reality, he is floating in space, he has no hair, the year is around 2199, and the world has been darkened by war. There are a few small differences from the vat scenario above: Neo's brain is located in a body, and the computer simulation is controlled by machines rather than by a scientist. But the essential details are much the same. In effect, Neo is a brain in a vat.
Let's say that a matrix is an artificially-designed computer simulation of a world. So the Matrix in the movie is one example of a matrix. And let's say that someone is envatted, or that they are in a matrix, if they have a cognitive system which receives its inputs from and sends its outputs to a matrix. Then the brain at the beginning is envatted, and so is Neo.
We can imagine that a matrix simulates the entire physics of a world, keeping track of every last particle throughout space and time. (Later, we will look at ways in which this set-up might be varied.) An envatted being will be associated with a particular simulated body. A connection is arranged so that whenever this body receives sensory inputs inside the simulation, the envatted cognitive system will receive sensory inputs of the same sort. When the envatted cognitive system produces motor outputs, corresponding outputs will be fed to the motor organs of the simulated body.
When the possibility of a matrix is raised, a question immediately follows. How do I know that I am not in a matrix? After all, there could be a brain in a vat structured exactly like my brain, hooked up to a matrix, with experiences indistinguishable from those I am having now. From the inside, there is no way to tell for sure that I am not in the situation of the brain in a vat. So it seems that there is no way to know for sure that I am not in a matrix.
Let us call the hypothesis that I am in a matrix and have always been in a matrix the Matrix Hypothesis. Equivalently, the Matrix Hypothesis says that I am envatted and have always been envatted. This is not quite equivalent to the hypothesis that I am in the Matrix, as the Matrix is just one specific version of a matrix. For now, I will ignore the some complications that are specific to the Matrix in the movie, such as the fact that people sometimes travel back and forth between the Matrix and the external world. These issues aside, we can think of the Matrix Hypothesis informally as saying that I am in the same sort of situation as people who have always been in the Matrix.
The Matrix Hypothesis is one that we should take seriously. As Nick Bostrom has suggested, it is not out of the question that in the history of the universe, technology will evolve that will allow beings to create computer simulations of entire worlds. There may well be vast numbers of such computer simulations, compared to just one real world. If so, there may well be many more beings who are in a matrix than beings who are not. Given all this, one might even infer that it is more likely that we are in a matrix than that we are not. Whether this is right or not, it certainly seems that we cannot be certain that we are not in a matrix.
Serious consequences seem to follow. My envatted counterpart seems to be massively deluded. It thinks it is in Tucson; it thinks it is sitting at a desk writing an article; it thinks it has a body. But on the face of it, all of these beliefs are false. Likewise, it seems that if I am envatted, my own corresponding beliefs are false. If I am envatted, I am not really in Tucson, I am not really sitting at a desk, and I may not even have a body. So if I don't know that I am not envatted, then I don't know that I am in Tucson, I don't know that I am sitting at a desk, and I don't know that I have a body.
The Matrix Hypothesis threatens to undercut almost everything I know. It seems to be a skeptical hypothesis: a hypothesis that I cannot rule out, and one that would falsify most of my beliefs if it were true. Where there is a skeptical hypothesis, it looks like none of these beliefs count as genuine knowledge. Of course the beliefs might be true — I might be lucky, and not be envatted — but I can't rule out the possibility that they are false. So a skeptical hypothesis leads to skepticism about these beliefs: I believe these things, but I do not know them.
To sum up the reasoning: I don't know that I'm not in a matrix. If I'm in a matrix, I'm probably not in Tucson. So if I don't know that I'm not in a matrix, then I don't know that I'm in Tucson. The same goes for almost everything else I think I know about the external world.
Let's say that a matrix is an artificially-designed computer simulation of a world. So the Matrix in the movie is one example of a matrix. And let's say that someone is envatted, or that they are in a matrix, if they have a cognitive system which receives its inputs from and sends its outputs to a matrix. Then the brain at the beginning is envatted, and so is Neo.
We can imagine that a matrix simulates the entire physics of a world, keeping track of every last particle throughout space and time. (Later, we will look at ways in which this set-up might be varied.) An envatted being will be associated with a particular simulated body. A connection is arranged so that whenever this body receives sensory inputs inside the simulation, the envatted cognitive system will receive sensory inputs of the same sort. When the envatted cognitive system produces motor outputs, corresponding outputs will be fed to the motor organs of the simulated body.
When the possibility of a matrix is raised, a question immediately follows. How do I know that I am not in a matrix? After all, there could be a brain in a vat structured exactly like my brain, hooked up to a matrix, with experiences indistinguishable from those I am having now. From the inside, there is no way to tell for sure that I am not in the situation of the brain in a vat. So it seems that there is no way to know for sure that I am not in a matrix.
Let us call the hypothesis that I am in a matrix and have always been in a matrix the Matrix Hypothesis. Equivalently, the Matrix Hypothesis says that I am envatted and have always been envatted. This is not quite equivalent to the hypothesis that I am in the Matrix, as the Matrix is just one specific version of a matrix. For now, I will ignore the some complications that are specific to the Matrix in the movie, such as the fact that people sometimes travel back and forth between the Matrix and the external world. These issues aside, we can think of the Matrix Hypothesis informally as saying that I am in the same sort of situation as people who have always been in the Matrix.
The Matrix Hypothesis is one that we should take seriously. As Nick Bostrom has suggested, it is not out of the question that in the history of the universe, technology will evolve that will allow beings to create computer simulations of entire worlds. There may well be vast numbers of such computer simulations, compared to just one real world. If so, there may well be many more beings who are in a matrix than beings who are not. Given all this, one might even infer that it is more likely that we are in a matrix than that we are not. Whether this is right or not, it certainly seems that we cannot be certain that we are not in a matrix.
Serious consequences seem to follow. My envatted counterpart seems to be massively deluded. It thinks it is in Tucson; it thinks it is sitting at a desk writing an article; it thinks it has a body. But on the face of it, all of these beliefs are false. Likewise, it seems that if I am envatted, my own corresponding beliefs are false. If I am envatted, I am not really in Tucson, I am not really sitting at a desk, and I may not even have a body. So if I don't know that I am not envatted, then I don't know that I am in Tucson, I don't know that I am sitting at a desk, and I don't know that I have a body.
The Matrix Hypothesis threatens to undercut almost everything I know. It seems to be a skeptical hypothesis: a hypothesis that I cannot rule out, and one that would falsify most of my beliefs if it were true. Where there is a skeptical hypothesis, it looks like none of these beliefs count as genuine knowledge. Of course the beliefs might be true — I might be lucky, and not be envatted — but I can't rule out the possibility that they are false. So a skeptical hypothesis leads to skepticism about these beliefs: I believe these things, but I do not know them.
To sum up the reasoning: I don't know that I'm not in a matrix. If I'm in a matrix, I'm probably not in Tucson. So if I don't know that I'm not in a matrix, then I don't know that I'm in Tucson. The same goes for almost everything else I think I know about the external world.
The Matrix is a 1999 science fiction-action film written and directed by Larry and Andy Wachowski, starring Keanu Reeves, Laurence Fishburne, Carrie-Anne Moss, Joe Pantoliano, and Hugo Weaving. It was first released in North America on March 31, 1999, and in Australia on April 8, 1999, and is the first installment in the Matrix series of films, comic books, video games, and animation. The film depicts a future in which reality as perceived by most humans is actually a simulated reality created by sentient machines to pacify and subdue the human population, while their bodies' heat and electrical activity are used as an energy source. Upon learning this, computer programmer 'Neo' is drawn into a rebellion against the machines, involving other people who have been freed from the 'dream world' and into reality.
"I dreamed I was a butterfly, flitting around in the sky; then I awoke. Now I wonder: Am I a man who dreamt of being a butterfly, or am I a butterfly dreaming that I am a man?"
ZHUANGZI
ZHUANGZI
Once Zhuangzi dreamt he was a butterfly, a butterfly flitting and fluttering around, happy with himself and doing as he pleased. He didn't know he was Zhuangzi. Suddenly he woke up and there he was, solid and unmistakable Zhuangzi. But he didn't know if he was Zhuangzi who had dreamt he was a butterfly, or a butterfly dreaming he was Zhuangzi.
Zhuangzi is thought to have lived during the reign of King Hui of Liang and King Xuan of Qi, in the span from 370 to 301 BCE. Zhuangzi was an influential Chinese philosopher who lived around the 4th century BCE during the Warring States Period, a period corresponding to the philosophical summit of Chinese thought — the Hundred Schools of Thought, and is credited with writing—in part or in whole—a work known by his name, the Zhuangzi.
Zhuangzi's philosophy is skeptical, arguing that life is limited and knowledge to be gained is unlimited. To use the limited to pursue the unlimited, he said, was foolish. Our language and cognition in general presuppose a dao to which each of us is committed by our separate past—our paths. Consequently, we should be aware that our most carefully considered conclusions might seem misguided had we experienced a different past.
Zhuangzi argues that in addition to experience our natural dispositions are combined with acquired ones—including dispositions to use names of things, to approve/disapprove based on those names and to act in accordance to the embodied standards. Thinking about and choosing our next step down our dao or path is conditioned by this unique set of natural acquisitions.
Zhuangzi's thought can also be considered a precursor of relativism in systems of value. His relativism even leads him to doubt the basis of pragmatic arguments (that a course of action preserves our lives) since this presupposes that life is good and death bad. In the fourth section of 'The Great Happiness' Zhuangzi expresses pity to a skull he sees lying at the side of the road. Zhuangzi laments that the skull is now dead, but the skull retorts, "How do you know it's bad to be dead?
Zhuangzi is thought to have lived during the reign of King Hui of Liang and King Xuan of Qi, in the span from 370 to 301 BCE. Zhuangzi was an influential Chinese philosopher who lived around the 4th century BCE during the Warring States Period, a period corresponding to the philosophical summit of Chinese thought — the Hundred Schools of Thought, and is credited with writing—in part or in whole—a work known by his name, the Zhuangzi.
Zhuangzi's philosophy is skeptical, arguing that life is limited and knowledge to be gained is unlimited. To use the limited to pursue the unlimited, he said, was foolish. Our language and cognition in general presuppose a dao to which each of us is committed by our separate past—our paths. Consequently, we should be aware that our most carefully considered conclusions might seem misguided had we experienced a different past.
Zhuangzi argues that in addition to experience our natural dispositions are combined with acquired ones—including dispositions to use names of things, to approve/disapprove based on those names and to act in accordance to the embodied standards. Thinking about and choosing our next step down our dao or path is conditioned by this unique set of natural acquisitions.
Zhuangzi's thought can also be considered a precursor of relativism in systems of value. His relativism even leads him to doubt the basis of pragmatic arguments (that a course of action preserves our lives) since this presupposes that life is good and death bad. In the fourth section of 'The Great Happiness' Zhuangzi expresses pity to a skull he sees lying at the side of the road. Zhuangzi laments that the skull is now dead, but the skull retorts, "How do you know it's bad to be dead?