Always learning. Always wrong.
Problems in Philosophy
Free Will in Five Minutes
Apr 21st
There are two popular theories about free will which are incompatible with each other and with reality. The positive position is that we, as human beings, have this magical thing called free will that is independent of physics and causality, which allows us to make truly “free” choices. The negative position is that we are mere particles, and so there is no free will and life is meaningless.
The error in both of these theories is that they are conflating two propositions which are actually independent of each other:
- Human beings can do whatever they want.
- The decisions of human beings are not wholly deterministic.
The positive position is that both of these statements are true. The negative position is that they are both false: our decisions are deterministic, therefore we cannot do whatever we want.
But hold on a second, and let us see if we can use some Science here. Proposition 2 is false. The decisions of human beings are wholly deterministic, because the universe is entirely deterministic.¹ Does this mean that Proposition 1 is also false, as the popular negative position holds?
Of course not. Your actions are entirely determined by your wants. All determinism tells us is that our wants themselves are entirely determined by physical processes. This even has the advantage of being intuitive²: even when I do things I don’t want to do (like math homework), I have some greater want in mind that makes them worthwhile (like graduating from college).
You can do whatever you want. But as the staggeringly important philosopher Robert Nozick has observed,
No one has ever announced that because determinism is true thermostats do not control temperature.
This position is known as compatibilism.
1: Some accounts of quantum mechanics disagree, but the lack of determinism in those accounts certainly has nothing to do with human decision-making processes.
2: Though please remember that intuition is not any kind of proof, and not very good evidence either.
Escaping the Chinese Room
Mar 16th
Let’s say I have a computer program that speaks Chinese as well as a human native speaker of the language; I’ve had people who speak fluent Chinese talk to the program using instant messages for an extended period of time, and none of them have been able to figure out that my program isn’t another person. Now, suppose I print out an English version of this program and store it in some filing cabinets in a room. I go into the room, lock the door, and begin exchanging messages with a Chinese speaker by passing notes under the door. Each time a note is passed in, I follow the written steps of my program to figure out what reply to make, write that down, and then slide it back under the door. Like before, anyone reading the notes I pass back under the door is completely unable to tell that I’m not a native Chinese speaker.¹
John Searle formulated this thought experiment so that he could ask whether the person in the room could be said to understand Chinese in the same sense as a native speaker. If we admit that they are not the same, as it seems we must, we must also admit that a computer running the program likewise does not understand Chinese, and thus that it is impossible for a computer to think and understand as humans do.
The problem with this conclusion is that it requires that neurons and brains possess qualities which transistors and computer chips do not. Searle suggested that neurons have “causal properties” which cannot be detected by outside observers but nevertheless give rise to the mind and consciousness. Another possibility is that, as Sir Roger Penrose has proposed, microtubules in neurons exploit quantum effects to perform hypercomputation.
I would like to propose that brains are actually made out of magical fairies, which is equally well-supported by the available evidence and easier to explain to young children.
Or perhaps it is time to go back and double-check the logic leading to Searle’s conclusion.
The crux of Searle’s argument is that brains do this thing called “understanding” that computer programs (algorithms, to be more precise) cannot. If we are reductionists (and we should be!), then understanding is something that can be explained in entirely physical terms. Either there is an as-yet-undetected Fairy Force at work in human brains, or the Chinese room is capable of understanding.
There is no choice but to bite one of these bullets; I find the latter more palatable.
1: Except for how long it takes for me to make my replies. We can ignore this for the sake of the thought experiment, but I should still note that it would take an unimaginably huge amount of time to walk through every step of a complex computer program that was designed to run on a machine that performs 2 or 3 billion operations each second.
Escaping Mary’s Room
Mar 3rd
As soon as a philosopher begins talking about mental states as though they are fundamental or uniquely important things and not convenient abstractions for talking about particles bopping around in a particular way, you should know you’re in trouble. It’s an unfortunately common variety of motivated thinking to come up with a grand theory of the universe that just happens to have the theorizer in the center; be wary.
While this is good advice, it is not really a counter-argument. There are arguments against dualisms in general, but I will instead be focusing on specific errors in these next couple posts, on the grounds that dealing with them is both more straightforward and more entertaining.
So. Mary’s Room is a thought experiment first formulated by Frank Jackson as follows:
Mary is a brilliant scientist who is, for whatever reason, forced to investigate the world from a black and white room via a black and white television monitor. She specializes in the neurophysiology of vision and acquires, let us suppose, all the physical information there is to obtain about what goes on when we see ripe tomatoes, or the sky, and use terms like ‘red’, ‘blue’, and so on. She discovers, for example, just which wavelength combinations from the sky stimulate the retina, and exactly how this produces via the central nervous system the contraction of the vocal cords and expulsion of air from the lungs that results in the uttering of the sentence ‘The sky is blue’. [...] What will happen when Mary is released from her black and white room or is given a color television monitor? Will she learn anything or not?
(Via Wikipedia)
Or, to put it another way, Mary is a person who has complete and exhaustive physical knowledge of everything about color and how humans perceive it, but who has never experienced it herself. If she then experiences it, can she be said to have acquired some (non-physical) knowledge she didn’t previously possess?
This thought experiment has been the subject of a great deal of debate among philosophers of mind. Which is silly, because the answer is trivially and obviously no.
Mary’s complete and exhaustive physical knowledge of human color perception must include knowledge of how her own brain experiences colors. The human brain deals with experiential knowledge as well as explicit verbal knowledge; I know how to ride a bike, but this has nothing to do with my knowledge of gyroscopes and angular momentum. But this does not and should not lead us to say that my knowledge of how to ride a bike is somehow non-physical. It is merely represented and processed differently by my brain.
And yet somehow people have been arguing about this (usually badly) for more than 20 years. Five or ten minutes should really be enough. Let’s move on.
Tomorrow: I do not understand Chinese.
How To Obliterate Solipsism Before Breakfast
Dec 19th
Wikipedia tells us that:
Solipsism is the philosophical idea that only one’s own mind is sure to exist.
This is obviously dumb and wrong, but philosophers tend to be quite bad at backing up that intuition. Typically, they claim that solipsism is ridiculous or meaningless or has bad consequences (though usually with bigger words), and then dismiss it. Some agree that it is true, say what a great tragedy it is, and then carry on as if it were false for lack of anything better to do. I find this very annoying, because refuting solipsism isn’t actually very difficult if you approach it from the right angle.¹
To better argue against it, I’ll clarify Wikipedia’s definition of solipsism further and break it down into two distinct claims:
- One’s mind is sure to exist.
- Nothing else is sure to exist.
The first claim dates back to Rene Descartes’s declaration that “cogito, ergo sum;” I think, therefore I am. The cogito argument has been (justly) criticized as relying on unjustified assumptions about individual identity, but we can pare it down to a weaker (and less elegant) argument along the lines of “thinking is occurring, therefore there is a thinking thing.” This isn’t precisely equivalent to that first claim above, but we can reword it as “A mind is sure to exist” without doing too much damage to the philosophy of solipsism; it’s certainly not a clear enough victory to qualify as obliteration, so I’ll turn to the second claim.
I love strong negative claims because they make it very clear what it’ll take to refute them. In this case, if someone can demonstrate that anything other than a single mind exists, solipsism has no choice but to vanish in a puff of logic.² But before I can do that, I should probably nail down the definitions I’m using and get rid of as much ambiguity as I can manage.
So what does it mean for something to exist, then? Most definitions of existence share a common form: something exists if it is present in a specific system. For example, I could say that something exists in the everyday sense if it is present in the system of the physical universe. By this definition, dinosaur fossils exist, but the invisible dragon in my garage does not. More abstractly, I could say that the integer 5 exists in the formal system of arithmetic, but bleem, the integer between 3 and 4, does not. These kinds of existence are not interchangeable, or else I could say that the integer 5 physically exists, and that dinosaur fossils are mathematical symbols.
Unfortunately, any kind of existence that relies on such a system can’t be the existence that solipsism is concerned with, as systems describe the relationships between things. If I have a relationship between two things, then at least one of those things must be something other than the mind I already know about, and my definition would be assuming what I’m trying to prove. Circular logic is a no-no, so the definition of existence I’m looking for must be an absolute one, that allows me to say that a thing either does or does not exist regardless of its relationship to anything else.
But now I’m trapped. If I can’t use relationships to determine existence, then I can no longer say that “thinking is occurring, therefore there is a thinking thing,” because logical implication is a relationship in the system of logic! It is no longer certain that a mind exists, and so solipsism’s first claim is false.
There is no reasonable definition of existence for which solipsism is true; it is a philosophical position which is logically impossible. On the bright side, it provides a thought experiment that’s helpful for clarifying the nature of existence, which is a bad thing to be confused about when trying to answer other philosophical questions.
1: There are philosophers who have made this argument before, but for some unfathomable reason they don’t get very much attention.
2: Credit for this phrase is due to the tragically dead Douglas Adams.