Raman, Thought Experiments

Thought Experiments and Empirical Experiments (2/2)

(This post is the second in a two-part series on the relationship between thought experiments and empirical experiments. The first post can be found here.)

I am going to knock out all of the design theory up front so bear with me for one paragraph and then we can get back to the fun stuff. According to Roger Kirk, who wrote one of the most widely used textbooks for research design in the behavioral sciences, “Experiments are characterized by the: (1) manipulation of one or more independent variables; (2) use of controls such as randomly assigning participants or experimental units to one or more independent variables; and (3) careful observation or measurement of one or more dependent variables. The first and second characteristics—manipulation of an independent variable and the use of controls such as randomization—distinguish experiments from other research strategies” (Kirk 1968). A good experiment isolates the variables being studied to remove outside influence and allow researchers to make strong, causal claims about relationships between variables.

Now that the basic theory is out of the way, lets see how it applies to empirical experiments. Good empirical experiments start with at least one scientific hypothesis (and usually one or more statistical hypotheses) that is falsifiable and offers one or more predictions that can be experimentally tested. Because good empirical experiments isolate from and control for outside influences, they are consistently reproducible. Good experiments allow scientists to assess the accuracy of the predictions they made based on their hypotheses and accordingly determine whether the hypotheses themselves are supported or rejected by the data.

Thought experiments follow a similar model. Like empirical experiments, thought experiments isolate particular variables in order to study the relationship between them. This generally takes the form of creating a hypothetical situation in which all of the parameters of the experiment are set by the philosopher in order to limit consideration to the specific decisions or phenomena being studied. The purpose of this is generally to understand how something would be in an ideal case, free from the confines of circumstance, so that decisions themselves can be isolated from their circumstances and general statement of principle can be made. These statements of principle, like predictions from hypotheses, are then tested with further experiments to find circumstances in which they do not hold or to show that they do hold in cases where they were previously believed not to. To see an example of this, check out my series of posts on the Trolley Problem/Surgeon Problem (Part 1, Part 2, Part 3).

These two types of experiment compliment each other well because the things thought experiments are good for, making falsifiable predictions and assessing the implications of facts and principles on real-world circumstances, are the same things empirical experiments do poorly. Because empirical researchers face a tradeoff between internal and external validity, the most internally conclusive experiments are the ones that require the most conceptualization to put in context and evaluate. Similarly, empirical research provides a way for philosophers to determine if the assumptions on which they construct their theories are consistent with what we “know” about how the world works and human behavior. Neither type is useful without the other, and everyone would do well to become familiar with both.

It is not a coincidence that many of the greatest thinkers in the history of humanity were both scientists and philosophers. Many of humanity’s greatest achievement have come from people who were willing and able to harness the analytical and predictive power of both disciplines and use them in tandem. It is vitally important that scientists have a working knowledge of philosophy and analytical thinking, and that philosophers appreciate empirical research and the sciences. In a society that tends to sort people by academic discipline and force them to specialize early, there is perhaps no rarer but more vital skill than that of thinking across disciplines and recognizing that knowledge is most powerful when it is most complete.

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This brings us to the conclusion of my blog on thought experiments. Thank you to everyone who has read, commented, and given me feedback; I sincerely hope that you have enjoyed reading my posts as much as I have enjoyed writing them. When I started this blog, I had to chose something to put under the title at the top of the page. I settled on the quasi-official motto of western philosophy: “the unexamined life is not worth living.” I believe very strongly that thought experiments are an excellent tool for this kind of critical examination, and I am glad to have been able to share this tool with you over the course of the last several weeks.

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Raman, Thought Experiments

Thought Experiments and Empirical Experiments (1/2)

If you are a natural-science person (or a psychology person), you will most likely have to take a class in experimental design while you are here at Penn State. Experiments are the cornerstone of the scientific method, so it makes sense to devote significant attention to understanding how they work, what makes some better than others, and what their limitations are. For the last several weeks, I have talked about thought experiments and the role they play in philosophy and science (If you haven’t already and you are interested in thought experiments in science, check out my posts on Relativity and The Importance of Thought Experiments to Modern Physics). For these last two posts, I want to shift gears and talk about the relationship between thought experiments and empirical experiments.

Over the course of writing this passion blog, one of my major objectives has been to dismiss the notion that thought experiments are something people use to speculate about the world from their armchairs without actually observing anything, and that empirical experiments are “better” for learning about “real” things. Empirical experiments and thought experiments are both important tools people can use to understand our world, and they each have their own distinct purposes. Especially in fields like Physics and Neurology, thought experiments can help scientists both to determine what kind of empirical experiments to perform and how to make sense of the results of those experiments. There are certainly places where empirical experiments are “better” than thought experiments, but there are also places, even in the natural sciences, where thought experiments are “better” (one of which is in determining what makes a given method of examination “better”, but this is a subject that requires a more thorough treatment than I am prepared to offer here).

In the 21st century, one of the places where empirical and thought experiments have both come into conflict and complimented each other tremendously is in neurology. If you are interested in neurology, philosophy of science, or intellectually stimulating conversation in general, I highly recommend that you take 13 minutes and 22 seconds to listen to a Philosophy Bites podcast interview with Barry Smith on the interaction between these two tool sets for exploring the mind (the interview can be found at http://philosophybites.com/2008/09/barry-smith-on.html) and, if you enjoy that, as many of their neuroscience focused interviews as you can handle (which can be found here http://philosophybites.com/neuroscience/). Essentially, Dr. Smith lays out the role that each method has in advancing both neuroscience and the various related philosophical disciplines. To him, philosophers are too skeptical of evidence from empirical experiments that contradicts their expectations, which he believes is hampering the discipline’s progress. On the other hand, he recognizes that philosophers were the first people to raise the kinds of questions neuroscience explores, that their thought experiments provided an important starting place for the empirical research, and that, in his own words, when it comes to “pathologies and neurological breakdown, help is needed by the neurologists and biologists from the philosophers to help to explain how to characterize these experiences, to understand what they’re like, and to contrast them with normal experience.”

In my next post, I am going to discuss what makes a good empirical experiment, what makes a good thought experiment, and compare and contrast the two.

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Raman, Thought Experiments

Physics or Philosophy

Last week I wrote about the value of thought experiments in the sciences. To illustrate my point, I used the example of Einstein’s theory of relativity and talked about how scientists never could have arrived at the concept empirically and the fact that they had still been unable to prove it. Apparently my challenge was accepted, because earlier today scientists at the Laser Interferometer Gravitational-Wave Observatory (LIGO) confirmed that they were able hear the sound of two black holes colliding 1.3 billion light years away by registering ripples in space time. The results announced today are the first empirical conformation of the existence of gravity waves, which Einstein predicted as part of his general theory of relativity (which I discussed in last week’s post). It is also the first ever direct detection of black holes, which have been impossible to observe until now because of the fact that they do not emit any radiation. The fact that after 100 years of technological and methodological progress scientists have only now been able to confirm Einstein’s theory, and only with his research to tell them what to look for, shows how far ahead of his time Einstein was and further proves my point about the incredible power of thought experiments.

Rather than pick another though experiment to talk about, I want to give a quick overview of how thought experiments have driven the refinement/development of relativity, quantum theory, and many of the other most significant discoveries in physics of the last century. This is not an appropriate venue for an overview of the theories themselves (and I would certainly not be qualified to give one even if it were), but there are a few unifying themes that make thought experiments particularly useful in these fields.

In a review of a recent book about Einstein and Schrödinger, the author notes that “each had a strong philosophical bent, which shaped his worldview” and that “those philosophical influences contributed to their mutual dislike of the probabilistic nature of quantum mechanics.” One of the main reasons that physicists often resort to using thought experiments to make their points is that the theories they work with often deal with unobservable phenomena that are either far too large (think black holes), far too small (think fundamental particles), or far to abstract (think space time or the alternate dimensions required by string theory) for people, even theoretical physicists, to conceptualize (as a side note, all of those examples started as thought experiments). Thought experiments, when well designed, allow physicists to think through conceptual problems without getting bogged down in cumbersome details. The physicists can then work backwards to test their intuitions empirically. They are not always right, Einstein was wrong about quantum entanglement and most modern physicists believe that Schrödinger was wrong about superposition, but the thought experiments give them a starting place for empirical testing.

Stephen Hawking famously said that “philosophy is dead” because there was nothing else for us to learn about the world without hard data. While his commitment to data and evidence may resonate with many in STEM fields, you unfortunately will not be rid of us philosophers so easily. The story of the last century of physics is philosophy first, math later. In the same interview, Hawking himself admits that scientifically testing his preferred unifying theory, called “M Theory,” would require a particle collider the size of the Milky Way galaxy; but he defends his commitment to it with synthesis, logical syllogism and thought experiments: much like a philosopher would. If Stephen Hawking is correct that philosophy is dead, someone should probably tell Stephen Hawking: he may be out of a job!

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Raman, Thought Experiments

Brain in a Vat

Imagine that a mad scientist created a machine into which he could place a human brain. This machine, which we shall call a “brain vat”, would not only keep the brain alive and functioning, but it would allow the scientist to create virtual stimuli and feed them directly into the brain. The brain would register all of these stimuli in exactly the same manner as normal human sensory experiences, as these are already interpreted as electrical signals anyway. In this way, the scientist could create an entire fictitious world that, to the captive brain, would feel completely normal.

What if I told you that you, the person reading this post, were not actually a human being but instead merely a brain in a vat? You may attempt to prove me wrong, but you would find that quite difficult, and you would not be alone. This thought experiment has puzzled philosophers since it was first proposed in 1641 by René Descartes (Though Descartes’ experiment used an evil demon in place of a vat. The vat was proposed Gilbert Harman in 1973 to update the experiment to accommodate modern understandings of psychology and neuroscience). The idea of the brain in a vat (BIV) is that no brain could ever know whether it was in a skull or a vat, and could therefore never know whether everything it experiences is real or an illusion.

Descartes answered his own version of the experiment with his famous cogito, ergo sum (“I think, therefore I am”). I do not have the time or space to fully explain the Cogito in this post, but I highly encourage everyone to read about it. Essentially Descartes argues that either the world is real and he is experiencing it, or he is being deceived. Even if he is being deceived, he still exists in order to be deceived. Therefore, the fact that he can question his existence is sufficient to prove that he exists.

Importantly, the Cogito does not prove that he is not being deceived (or, to use the BIV terms, that he is not a brain in a vat). What Descartes instead proves is that he is something, not necessarily a human or even necessarily a brain, but something. Based on the Cogito, a BIV can know that it exists, but it cannot know anything else about itself or the world.

This thought experiment has implications for ethics (if you are a brain in a vat and nothing else is real, there is nothing wrong with doing terrible things to others), epistemology (the study of knowledge and what it means/why it matters), our understandings of what it means to be human, and many other philosophical disciplines. Many scientists have also written about and studied this thought experiment for a variety of reasons and in a variety of contexts.

On a lighter note, if this all sounded very familiar, it may be because this thought experiment is the basic plot of The Matrix (though the matrix also includes some elements of the experiment from last week’s post, The Allegory of the Cave). On an even lighter note, here are some funny cartoons about this thought experiment. Have a great weekend, even if it’s all an illusion!
BIV Cartoon

BIV Cartoon 2

(cartoons from https://coelsblog.wordpress.com/2014/08/14/a-scientific-response-to-the-brain-in-a-vat/.)

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Raman, Thought Experiments, Uncategorized

The Allegory of the Cave

Ok, so before I start commenting on specific thought experiments I want to stop and explain what thought experiments are and why they are important. Often times philosophers find themselves dealing with very conceptual, multifaceted questions that are too abstract and complex to meaningfully discuss. To get around this, they will often create thought experiments. Thought experiments, like science experiments, seek to isolate the variable being studied to allow for meaningful exploration. This usually takes the form of setting up a fictitious scenario in which people are confronted either with a purer form of the initial question or some allegorical situation.

To illustrate this, consider Plato’s famous “Allegory of the Cave” (or “Allegory of the Den” depending on the translation). In the allegory, Socrates (Plato’s teacher and the narrator of all of Plato’s dialogues) asks a friend named Glaucon to imagine that there are prisoners in a cave chained against a wall. Behind them there is a fire and a walkway (see image). Throughout the day, puppeteers walk down the walkway with puppets that cast shadows on the wall. The men can see the shadows, but they cannot see the objects themselves. If the shadow were of a book, the prisoners, knowing nothing else of books, would say that they see a book. We know that what they see is merely a shadow of a book, an approximation of the real object, but they would not understand this.

Socrates asks Glaucon to consider what would happen if a prisoner was released and able to see the sun and real objects in their true forms. Glaucon observes that he would likely be put-off at first, but that he would soon come to understand that these new objects were real and that the old ones were all shadows. Socrates then asks what the man would do if he was taken back into the cave and made to again watch the shadows. Glaucon points out that he would likely be frustrated by the triviality of it all, and that he would be especially incapable of trying to assign meaning to the shadows like the other men, since he would know that the shadows were not really the objects the men assumed they were.

Plato wants us to learn a few things from this allegory. Specifically, he trying to illustrate the life of people who do not understand his theory of forms. The theory of forms holds that the universe has a creator and that there exists only one of each object/concept in the world, which is located in the mind of the creator. According to Plato, the physical incarnations of these forms (the name given to the original object/concept) are merely copies of the forms and are therefore imperfect. Plato equates these copies to the shadows on the walls of the cave and himself to the man who has been let out to see the original objects, the forms.

While few people seriously believe his theory today, there is still much to be learned from the allegory. While Plato intended it to represent ignorance of the forms, it can really be used with any kind of ignorance. It is also commonly used to illustrate the concept that, while we develop perceptions of objects in our minds, these perceptions are distinct from the objects that created them and not all of our “knowledge” about these objects is correct.

Hopefully this has helped you to see how thought experiments can be useful in illustrating complicated concepts. I picked an easier one for the first post, but I will try to get into some more complicated and abstract ideas as the semester progresses. On a side note, I am trying to decide whether or not to discuss paradoxes on this blog. They have a completely distinct purpose from thought experiments, but they are also useful ways of thinking about tough questions and force readers to challenge their minds. If you have an opinion, let me know in a comment.

 

platoscave

https://faculty.washington.edu/smcohen/320/cave.htm

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