The modern American philosopher Hilary Putnam popularized a well-known thought experiment highlighting the problem of skepticism and our knowledge of reality. To understand Putnam’s experiment we need to consider how we normally obtain knowledge of reality. Our knowledge of reality usually begins with sensory input. While each of our five senses perceives the world according to their individual means, I will use seeing as an example. Light is reflected off of objects and enters through our eyes which focus an image of these objects to the back of our eyeball where it hits our optic nerve. Our nerve transforms this image into electrical/neural impulses that travel through the optic nerve up to where it is plugged into the brain. The brain then processes these impulses where they are transformed into an image in our mind. What our minds experience is an image of the outside world similar to how a television projects an image captured by a television camera. 

In Putnam’s thought experiment, you imagine that your brain has been severed from the nerves connecting it to your senses (eyes, ears, nose, etc.) and has been removed from you skull and placed in a vat filled with the nutritional fluid necessary to keep your brain alive and functioning. Electrical wires have been spliced into your sensory nerves that are connected to the sensory inputs in your brains. The other ends of these wires are connected to the outputs of a giant super computer. A man sits at the keyboard of this super computer inputting data. This data is transformed into electrical/neural impulses that travel through the spliced wire/sensory nerves and into your brain. The brain processes this information as if it were from your senses. Hence, you have whatever image the man at the keyboard wants you to have. Suppose he inputs data that you are sitting in a café in France drinking an espresso. He includes all the usual sensory data, including the smell and taste of the coffee, the hardness of the chair and table, the cool breeze blowing by, the sounds of the traffic, and the view of the Eiffel tower. You experience all of this exactly as if you are really there. In such a situation, you would have no idea that you (or at least your brain) are actually sitting in some vat in some laboratory. 

In 1999, Putnam’s thought experiment became the basis of a megahit movie, The Matrix. However, Putnam was not the first to suggest that there may be a problem with perceiving and knowing reality. A number of philosophers have wrestled with this problem. This brings us to your assignment.

In Module/Week 5’s Reading & Study folder there are 3 short readings. Your assignment is to read them and then write an essay with a minimum of 600 words (in MLA, APA, or Turabian format) addressing some of the following questions. You must address the first question, but then you are free to consider any of the others.

While you are free to quote from sources, quotations will not count towards the minimum word count. Late submissions will not be accepted without the instructor’s approval. Plagiarism of any kind will result in a 0 for the assignment and may result in being dropped from the course.

A word about the readings: The first reading is a synopsis of The Matrix. You may have seen the movie and so this would function as a review for you. If you haven’t seen the movie, you may choose to do so. However, you should know that the movie is rated R for language and violence. It is not necessary to view the movie to fulfill the assignment as the synopsis is enough to consider the questions. The second reading comes from Plato’s classic work, The Republic. It is in the form of a dialogue between Socrates and Glaucon, a brother of Plato, and contains the famous cave allegory. The final reading is a section from Meditation I from Meditations on First Philosophy by Rene Descartes who offers some reasons to doubt his senses.

Questions to consider:

1.      Compare and contrast The Matrix with the readings from Plato and Descartes. What are some similarities and differences?

2.      Can we prove the world we are experiencing is real? How do we know we are not dreaming, living in a Platonic cave, or trapped in some sort of matrix?

3.      At the end of the cave allegory, Socrates implies that most men would want to escape the cave and see reality as it really is. However, in his betrayal of Morpheus, Cypher implies that it is better to live in the artificial world of the Matrix. Which is better: the harshness of reality or the “ignorance is bliss” of illusion? Defend your answer.

4.      Since much of our knowledge is based on sense experience, and since our senses are imperfect and can be deceived, can we ever be certain that our beliefs are true? Defend or explain your answer.