Wednesday, June 27, 2007

The fictional skeptic

The subject was brought up over at Pharyngula of how skeptics are portrayed in fiction. I left the following comment over there, and I'm cross-posting it here so my readers can know a bit more of what I'm up to:

I'm actually working on a skeptical fantasy book myself (which is going at the expected snail's pace for random-intellectual-tries-to-write-a-book). The world contains many typical magical elements, but with physical causes behind them. Of course, since magic doesn't actually work in our world, my solution was to go in and tweak the laws of physics for this world.

Being the scientist that I am, looking at the results of somewhat different physical laws turned out to be one of the most interesting parts of constructing this world. For instance, one of the first ideas I tried was the existence of magnetic monopoles. I later added in negative-mass matter in order to explain the ability of magic to seemingly violate conservation of energy. Putting these together allowed me a somewhat-plausible physical explanation for magic, which means within the context of the story it can be studied.

The major theme of the story is rational skepticism, particularly about religions. In it, a major world religion's history is thoroughly plumbed and it's revealed that it's completely wrong in many ways, and the one seed of truth in it leaves out the real interesting story that happened in the past.

Unfortunately, I haven't really been working on it much lately. Seeing that there might be some interest for a skeptically-themed story, however, I'll see if I can convince myself to get back to it.

It occured to me that if I talk about some aspects of it while writing it, it might get me back into working on it. So, I'd like to ask my regular readers a question: Would you be interested in reading about the process of writing it? There are many ways I could go about it, such as talking about the characterization, the building of the world, the designing of alternate physical laws, and how I'm fitting in themes of skepticism.

Leave a comment and let you know what you think (if you're unsure and would like a sample of what such a post might be like, feel free to say that). No pressure, of course; there's no reason I can't just create another blog to talk about it if the general traffic here wouldn't be interested in that. But if they would be, no reason not to keep it here.

Proceed with your information binge...

We're fucked

Comments are open to guesses as to which recent event I'm referring in the title. You may use post labels as a hint if you so wish.

Proceed with your information binge...

Tuesday, June 26, 2007


I ran into this comment on Wikipedia this morning which I couldn't help ripping apart:

Atheism as pseudo-skeptic

This seems like a pretty obvious part of the subject - atheism (or a-supernatural, if you wish - Buddhists sometimes claim to be atheistic without the "skeptic" label) relies on claiming the negative, and when they commonly claim that they are skeptics, they are following this topic to the letter. Is there really no sources commenting on this, or is it just being removed every time it's mentioned?

I mean, I know that I can't put it in here myself, because no matter how obvious it is, it would be OR [Original Research]. But surely some scholar somewhere has noticed that this pretty much applies to any atheist, right?KrytenKoro 08:11, 26 June 2007 (UTC)

You know, it's been a long time since I mocked anyone's grammar. So before further ado, let's laugh at "Atheism as pseudo-skeptic." Anyways, I left a reply to it there, but I'll expand on it a bit in this post. First, what I said in reply:

In order to be a pseudoskeptic, you have to deny something even when there's significant evidence for it (and of course, claim to be a skeptic). This is different from simply assuming the null hypothesis until otherwise is shown to be true. Almost all atheistic skeptics fall into the latter category, as they haven't seen sufficient evidence for any religion, so they simply proceed on with their lives as if no god exists.

As a parallel, let's say I come up to you and talk about Slood, a miraculous substance on the importance level of fire or water, which has gone previously undiscovered by humanity. However, I never actually show you any slood or give you evidence that it exists, instead asking you to believe it on faith. If, after you're sufficiently frustrated with me, you give up on me ever showing you evidence for slood and go on with your life as if slood doesn't exist, are you any less of a skeptic? Replace "slood" with "God" and you have your typical atheist. --Infophile (Talk) (Contribs) 12:19, 26 June 2007 (UTC)

Of course, that's a gross oversimplification of what it's like to be an atheist. To get that feeling, you'd have to add in years being brought up by parents telling you about the existence of slood, preachers claiming they see slood regularly but never showing it to you, and others promising to show you slood sometime in the future but never following through. If you express any doubt in the existance of slood, you'll either simply be executed as a slood-heretic or (if you're in a somewhat more civilized society) be read a random sampling of ten or so Doggerel.

If you ask people why you should believe in slood, you're told stories about all the great things slood is useful for, and why believing in slood makes you a better person. And then there are appeals to how bleak life would be if slood didn't exist. All this actually goes to show is that it might be nice if slood did exist, but it does nothing to show that this is actually the case.

You could try to get people to pin down what they believe slood actually does, but you'll end up with conflicting accounts. In the past, it seems that people believed slood was responsible for everything they didn't understand, from gravity to genetic transfer. When physical mechanisms for those were discovered, slood was no longer appealed to as an explanation for those, but was still used to fill in any other gaps in human knowledge. As more and more gaps closed, the definition of slood became fuzzier and fuzzier, until it was just some nice thing that helped out people somehow.

Almost by accident, a few testable claims about slood were actually made over the years. A few enterprising people then went and actually tested these claims to see if they would find evidence for slood. When tested, no evidence ever showed up. If slood existed one would have expected to find evidence for it, but since none showed up, isn't it logical to assume the non-existence of slood? Or at least, isn't it reasonable to go on with life as if slood doesn't exist?

Nope. If you assume slood doesn't exist, then you're a slood-denier. In the sloodist's world, there's no difference between not believing something and denying it. Especially since, to them, there actually is good "evidence" for the existence of slood (based on slood-faith, spurious "slood proofs," and poorly-controlled experiments). If you deny slood exists after all of that "proof," then there's just no helping you. And you claim to be skeptical on top of that? Oh, so you're a pseudoskeptic too.

* * * * *

You can see how crazy things get if you accept just any claim that's made without evidence for it. Go back up into that post and replace "slood" with virtually any ridiculous claim. It makes just as much sense to believe in the existence of slood without evidence for it as it does for God, fairies, or invisible pink unicorns. Just because you go on with your life as if they didn't exist doesn't make you a "pseudoskeptic."

Proceed with your information binge...

Friday, June 22, 2007

Ask your god this!

It seems I've been tagged for this by TheBrummell. First, the rules:

1. We have to post these rules before we give you the facts.
2. Players start with eight random facts/habits about themselves.
3. People who are tagged need to write their own blog about their eight things and post these rules.
4. At the end of your blog, you need to choose eight people to get tagged and list their names.
5. Don't forget to leave them a comment telling them they're tagged, and to read your blog

However, simply eight facts about me seems a bit dull. How about eight facts and two lies about me, in no particular order? I'm still giving you eight facts, so it fits the bill. Your challenge is to figure out which eight are true and which two are lies. If you're the religious sort, this might be a good time to test out how well Divine Revelation works, so see if your god will give you the answers.

Here are the "facts," in no particular order:

1. On multiple occasions, I have used a knife to assist in drinking Coke.
2. I consider myself a "Secular Humanist."
3. I consumed more alcohol before I turned 21 than since then.
4. I've watched the movies of the new Star Wars trilogy more times than I've watched the movies of the old trilogy.
5. In real life, the only nickname I've had with any staying power whatsover was "The Beast" (though it still didn't have much).
6. I avoid writing with pencils and chalk at all costs. The sound/sensation of the lead or chalk being scraped off just grates my nerves somehow.
7. I once got a fundamentalist Jewish Creationist to admit to the possibility of a non-divine origin of the universe.
8. In early high school, I thought I'd disproven Special Relativity.
9. My fashion sense consists of judging whatever is on top of the pile or in the front of the closet at a given time to be most appropriate.
10. I once dressed up as a Terry Pratchett character for Halloween - and more than one person recognized who I was (though at UW, this isn't necessarily surprising).

Also, I'm opposed to pyramid-memes on principle, so I'll just let whoever wants to pick this up and run with it.

Proceed with your information binge...

Thursday, June 21, 2007

Skeptic's Circle #63

The latest Skeptics Circle is now up, courtesy of Relatively Science.

Open thread as usual, but stealing ideas from Bronze Dog is FORBIDDEN, unless, that is, you're sure to point out that imitation is a form of flattery.

Proceed with your information binge...

Monday, June 18, 2007

Quiddle Me Vis #2

Although I haven't yet exhausted the recommendations from my last appeal, I am running a bit short on short things to do. With that in mind, I'm bringing this up again. Here's how it works this time: Ask me any question. If it's a silly question, you'll likely get a silly answer. If it's a serious question, you'll get a serious answer.

Whether you're puzzled over the definition of a quasar or you want my recommendation of which Terry Pratchett book to read first, now's your chance to ask. So get to it!

Proceed with your information binge...

Saturday, June 16, 2007

Why Skepticism? (Part 4)

Yes, it seems I keep finding new subjects to shoehorn into this series. Sooner or later, I'll probably either make up an index post for it or give it its own unique label (as previously done for my Skeptic's Circle posts). Anyways, this time I'm going to be discussing the subject of skepticism as we use it in contrast to other theories, and talk about what might rightly be termed "pseudoskepticism."

* * * * *

Since getting back to work for the summer, I've had a lot of free time on my hands to randomly browse the portion of the internet that isn't filtered (Hey, I get the job done; that's the important part). Much of my time has been spent doing various things on Wikipedia, from reading up on random information I'll likely never use (though Tremaux's Algorithm might come in handy in some video games if I can figure out a way to leave markings) to helping out improve some articles.

From the very concept of Wikipedia - "The free encyclopedia anyone can edit" - you might suspect that it would get overwhelmed by childish vandals changing random articles to say "Bob is a faggot!" and idealogues changing articles to state their distorted picture as fact. However, 99% of the time when you're on it, you'll tend to find a stable, neutral, well-written encyclopedia article. If you start to look behind the scenes, you'll get an idea of how this works: There's an immense bureaucracy set up to stop vandals, mediate disputes, and even ban unrepentant editors if necessary.

Of course, as old bad users are kicked out, new bad users will inevitably join in. So there's always going to be two editors fighting over the George W. Bush article on whether the lead should call him the "Greatest President" or the "Worst President," overwriting all the revisions of others to "Current President." It should come as no surprise that debates between woos and skeptics also flare up constantly.

Take a look at this case currently in arbitration (the highest level of dispute mediation): Wikipedia:Requests for arbitration/Paranormal. Essentially, the case is a battle between skeptics and woos both trying to get certain articles the way they want them. I won't comment too much on the specifics of the case here, go and read about it yourself if you're interested, but there's one particular part I'd like to point out. For a while, one of the woos was throwing around the term "pseudoskeptic" at all the skeptical editors, partly as a tu qoque for their use of "pseudoscience." Eventually, one of the skeptics decided to see if it was possible to include in this case a ruling relating to the use of this term:


24) "Pseudoskeptic" is a pejorative term and per WP:NPA and WP:CIVIL shouldn't be used to describe other editors or people mentioned in articles (unless it's a quote cited to a source). --Minderbinder 22:58, 25 April 2007 (UTC)

The entire debate on this section is quite long, so I won't quote it all here. However, you can go read it for yourself if you wish. If you do so, here's a little task for you: Using only the bold "Support" or "Oppose" statements, try to guess whether each editor is a skeptic or a woo. This particular issue unsurprisingly fell straight down party lines. There are also a bunch of people neutral to the issue who chimed in, and they all ended up against the word "pseudoskeptic" as well.

The debate here centered around two issues: Whether it's civil, and whether it's accurate. The debate on its civility wasn't as interesting, and is mostly just a Wikipedia let's-work-together-instead-of-fighting thing. It basically just amounted to some claims that it was civil because it had a clear definition and that it wasn't civil, but labels of "pseudoscience" were just as bad. A couple quick counterarguments and we can move past this part: "Bullshit" has a clear definition, but is uncivil. People involved in the debates were never called pseudoscientists; only certain subjects were called pseudoscience.

* * * * *

The question of whether it's accurate is the real meat of the issue. First of all, let's go to the original definition: "Someone who claims to be a skeptic but isn't." Seems simple enough, and a nice parallel to "pseudoscience." However, the way the term's come into popular usage derives a bit more from the way Marcello Truzzi described it: "Some who claims to be a skeptic but holds a position of denial rather than doubt; who takes the negative position rather than an objective position" (paraphrased from his explanation).

Is this an accurate description? Well, that's debatable. I'd go with a "sometimes" here, but before we get into that, I think it's important to know where Truzzi's coming from. Taken from Wikipedia:

Truzzi founded the skeptical journal Explorations and was invited to be a founding member of the skeptic organization CSICOP. Truzzi's journal became the official journal of CSICOP and was renamed The Zetetic, still under his editorship. About a year later, he left CSICOP after receiving a vote of no confidence from the group's Executive Council. Truzzi wanted to include pro-paranormal people in the organization and pro-paranormal research in the journal, but CSICOP felt that there were already enough organizations and journals dedicated to the paranormal. Kendrick Frazier became the editor of CSICOP's journal and the name was changed to Skeptical Inquirer.

After leaving CSICOP, Truzzi started another journal, the Zetetic Scholar. He popularized the term Zeteticism as an alternative to Skepticism, because the term Skepticism, he thought, was being usurped by what he termed "pseudoskeptics". A zetetic is a "skeptical seeker." The term's origins lie in the word for the followers of the skeptic Pyrrho in ancient Greece and was used by flat-earthers in the 19th century. Truzzi's form of skepticism was Pyrrhonism, as apposed to the Academic tradition founded by Plato, which is followed by most scientific skeptics.

Truzzi was skeptical of investigators and debunkers who determined the validity of a claim prior to investigation. He accused CSICOP of increasingly unscientific behavior, for which he coined the term pseudoskepticism. Truzzi stated,

"They tend to block honest inquiry, in my opinion. Most of them are not agnostic toward claims of the paranormal; they are out to knock them. [...] When an experiment of the paranormal meets their requirements, then they move the goal posts. Then, if the experiment is reputable, they say it's a mere anomaly."

So, the rough story is: Truzzi got tempted by some pro-paranormal advocates and tried to get them a voice in the journal. CSICOP lost confidence in him and kicked him out for this. He then lashed back at them with "Well, you guys go too far in denying things! This one might actually be true!" and came up with a pejorative name to call them.

An important note to this story is that Truzzi actually abandoned using the term "skepticism" to describe what he did, instead referring to it as "zeteticism." Now think about it: He's differentiating himself from those who described themselves as "skeptics" by describing himself as a "zetetic." He left the descriptor of "skeptic" intact, and just used a different term for his practice. If he wanted to just claim that his method was better, that would be one thing, but somehow, he then jumped to the claim that the skeptics weren't true skeptics - despite the fact that he just ceded the term to them. If you can follow the logic here, you've got one up on me.

* * * * *

But let's put aside his poor logic in coming up with the term "pseudoskeptic" for the time being. Let's also put aside the issue of the spurious complaints of pseudoskepticism (as Bronze Dog has that covered quite well). Let's talk about what skepticism should be.

Skepticism is a method primarily defined by its goal. This goal is to discern reality. Skepticism (in the theoretical pure form) is the best method of determining what is real and what isn't real. However, we don't know a priori what the best method of determining reality is. Some might even argue that the best method of discerning reality is an aspect of reality itself, and so we'd need to use it in order to best determine it. While this might seem like a Catch 22, we can actually turn this around and use it as a test for a method: The best method to determine reality must, when used to determine what the best method is, result in itself.

Now that we have some actual test to see what might work, let's see how it applies to various methods of gaining knowledge about reality:

Intuition - The problem with using intuition to guess at reality is that it's highly dependant on the person using it. This extends to intuiting the best method for determining reality. While one person might intuit that their intuition is infallible, another might intuit that divine revelation is better, and a third that the scientific method is better. In the end, this fails the test of revealing itself as the best method.

Acceptance - (Essentially, this method is to accept any proposition about reality as true until evidence contradicting it has been found (weaker forms will accept only any plausible explanation, any likely explanation, or any probable explanation).) Using this to determine the best method only results in every proposed method being considered the best. Obviously, this won't work.

Denial - (The opposite of acceptance, this method will never accept anything to be true.) Applying it to this question will then result in denying that it's the best, so this one flies right out the window.

Divine Revelation - (Accept the word of deities on reality.) If we apply this to our question, we run into a problem that the deities might not actually say anything on this subject. For people who claim they have, some say that deities have claimed this method as best, while others have given other answers (such as the scientific method) as best.

Reverse Science - (When given a proposition, attempt to find evidence that it is true. When sufficient evidence has been found, accept that it is true. If sufficient evidence can't be found, declare it false.) This method is the first one that will actually result in itself, mostly due to a huge bias towards confirming propositions inherent in it. If we take the proposition that "Reverse Science is the best method for determining reality," it's simple to find many cases where people operating under this principle have ended up with the correct answer and to contrast it with cases where other methods have resulted in wrong answers. There is one little problem in that if you start with a proposition such as "Divine Revelation is the best method for determining reality," you'll end up declaring that as true, so we'll have trouble arguing that this method is truly the best.

Pyrrhonism - (Also what Truzzi calls "Zeteticism.") This method is characterized as constant inquiry while never accepting anything as true or false. The problem when it comes to our current question is that it then gives us nothing to go on - we have no idea whether it's the best method or not. However, this alone doesn't rule out that it could be (though I'll talk about other problems with it later).

The Scientic Method - (When given a proposition, design an experiment that will return specified results if the proposition is false. If these results are obtained, declare it false. If not, design further experiments to test other ways it might be false. If not of these reveal it to be false, tentatively accept it to be true. Add in replication of experiments for added reliability.)

And I've saved the best for last. Here we have a method that seems to have shown great promise in determining reality. However, can we know for sure that it actually has done so, and hasn't just led us off onto the wrong tangent somewhere? We can't know for sure, but we can use our test here to see if it might be viable.

To scientifically test the proposition that science is the best method of determining reality, one method of experiment would be to set up a controlled environment for various people - a virtual reality if you will, such as a video game world. Program in laws of nature for this world that will affect the people interacting with it. Then, select various people to interact with this world and use different methods to determine its laws. Once their determinations are made, have someone who doesn't know which method resulted in which determinations judge the accuracy of the predicted laws.

A finding that some method resulted in closer laws to reality than science would be evidence against the proposition that science is best. However, finding that science came up with the best laws wouldn't prove it's best, as there could be some untested method that's better. However, if we keep going at it and test every conceivable method against science and find that science is always the best, we could tentatively accept that it is the best.

So, it's possible for science to result in the determination that it's the best method. The problem is that this experiment has never been performed, so we can't say for sure that it is. I'd really like to go out and actually do this, but I don't have the clout or resources to do so (if anyone else can and wants to, please go ahead).

However, despite this setback, we can use some inference from the real world to gauge how science has been doing. We could start with the proposition, "If science is the best method to determine reality, then societies that use science will determine reality better and faster than those who don't," and combine it with the proposition, "Societies who have a better grasp on reality will develop better technology which utilizes it." This results in the hypothesis that societies that emphasize science will show better technological advances than those who don't - which is exactly what we see in the world. Now, while this does present some compelling evidence for science, since this wasn't declared an experiment ahead of time, we have to beware of the Sharpshooter Fallacy and not use this as definitive evidence after the fact.

Now, let's get back to Pyrrhonism, the only other method we haven't ruled out. It comes with a few big problems which should really make us wary of it. The first of these is that it never rules out any proposition. This means that as time goes on, we'll amount more and more possible phenomena and explanations, and we'd have to consider more and more in solving any particular problem. In the end, it just gets overwhelming. We have no method of narrowing down the list.

Science, on the other hand, provides us a method of discarding bad theories: By testing them and finding contradictory evidence or not finding expected supporting evidence. This method of discarding theories isn't just something claimed by science, it's also deductively supported by some elementary logic.

In the end, Pyrrhonism gives many explanations of reality, some of which might be right. Science, on the other hand, gives us a few explanations of reality of which most are probably right. Science also allows us to devote time and money on the theories we think are most probably right so that we can delve deeper and expand on them rather than repeatedly performing the same test to show that Astrology still doesn't work.

It should be little surprise then that skepticism as practiced by me and the majority of this community uses science as the core method and is thus commonly labeled "scientific skepticism." There are many other practices that add into this to refine it (such as demanding that extraordinary claims require extraordinary evidence - one of Truzzi's positive contributions to the cause), but at the heart, it's just science.

* * * * *

So, this leaves us with the question of what exactly pseudoskeptics are. Scrapping Truzzi's biased definition, we go back to pseudoskeptics being people who claim to be skeptics but aren't. As I see it, there are two types of people who might fit into this category.

The first of these is anyone who starts a post with "I used to be a skeptic but..." These people generally use this to try to lend some credibility to whatever woo they're promoting, by implying that there was something that convinced them the woo was superior. Many of them, however, fail to understand what being a skeptic actually means, and that if the evidence actually supports it, it's possible to be a skeptic and believe in anything. When they say they're no longer a skeptic, they're really just shooting themselves in the foot with this line of argument and admitting that they no longer care about what the evidence shows.

The other type of these people is actually not far off from what Truzzi characterized as pseudoskeptics. These are people who use "skeptic" as a euphemism for "denier." A common modern form is the "Global Warming skeptic," who isn't just being skeptical about the issue and looking at what the evidence points to, but is instead denying Global Warming (either on political grounds or because it seems implausible to them at first glance) and using spurious arguments to support their assertion.

It might not be easy, but it's my hope we can retake the term "pseudoskeptic" to refer to these types of people. It might not be easy; the term's picked up a lot of baggage. But if we backed off from a fight because it wasn't easy, we wouldn't be skeptics, now would we?

Proceed with your information binge...

Wednesday, June 13, 2007

The Modus Tollens Exception

"Absence of evidence isn't evidence of absence."

You've probably heard this line many times before, and you've probably heard it abused almost all of those times. It's a particular favorite of people who want to leave open the possibility of their pet supernatural (or just unconventional) belief which has absolutely no evidence supporting it. However, there are a few problems with this line of reasoning.

This statement contains within it a common linguistic assumption which has indirectly led to many logical errors and misconceptions. The statement can more clearly and accurately be stated as "Absence of evidence isn't necessarily evidence of absence." This should be contrasted with the meaning of "Absence of evidence is never evidence of absence." The dropping of "necessarily" from the initial (true) statement changes both its denotational and connotational meaning, but it's something that happens in casual speach, especially when dropping it leaves a line that's much catchier.

The reason it's crucial to leave in "necessarily" is that the statement has a big exception to it. This exception is for when you've actually looked for evidence - something that's actually happened in most cases where this mantra is being used to defend someone's belief, thus making their use of it fallacious. When you've appropriately looked for evidence for a claim and didn't find any, you can put this into the Modus Tollens argument form (slightly modified) to use this as evidence that the claim is false.

The basic form of Modus Tollens is:

If A, then C.
Not C.
Therefore, not A.

In this case, we modify it to turn A into a union of A and B, getting the form:

If A and B, then C.
B and not C.
Therefore, not both A and B.
Therefore, not A.

In this case, we're using A as some claim, B as a means of investigating that claim, and C as possible evidence that could be found to support that claim.

Let's go through an example to illustrate how this works, such as the claim that there's a full-size rhinoceros in the room. Now, we'll normally have no evidence that there is a rhinoceros in the room, and it's actually quite simple to extend this into evidence that there is no rhinoceros in the room:

If there is a full-size rhinoceros in the room (A) and I look around the room in every area large enough to hold a rhinoceros (B), then I will see a rhinoceros in one of these areas (C).

I looked around the room in every area large enough to hold a rhinoceros (B), and I did not see a rhinoceros in any of them (not C).

Therefore, either I did not look thoroughly enough, or there is no rhinoceros in the room (not both A and B).

However, since I did look thoroughly enough (B), there is no rhinoceros in the room (not A).

This principle is quite powerful, and it in fact lies beneath one of the fundamental properties of science: Falsification. Putting arguments into this form is exactly what allows us to test and possibly falsify them. If we assume that absense of evidence isn't evidence of absense, then we've thrown the possibility of falsifying almost anything right out the window.

Proceed with your information binge...

Thursday, June 07, 2007

Skeptic's Circle #62

The latest Skeptics Circle is now up, courtesy of Polite Company.

Open thread as usual, but pointing out how I use this same format for announcing every Skeptics Circle but never bother to copy and paste it is FORBIDDEN.

Proceed with your information binge...

Monday, June 04, 2007

Physics Q&A #2: The Fundamental Forces (part 2)

(Note: I have some diagrams I want to add in, but I don't have access to them on this computer. I'll put them in when I get home from work.)

Welcome back to the concluding part of this 3-part Physics Q&A. If you haven't already, I recommend you go back and read the first two parts of this entry. If you haven't read them, you'll likely be quite lost.

This time, we're going to tackle the two most complicated forces: The strong and weak nuclear forces. Of these two, the strong is the simpler one, so let's start there.

The Strong Nuclear Force

While electromagnetism works off of the electric charge of particles, the strong nuclear force works off of color charge. Of all the existing particles, only quarks and gluons have color charge, so these are the only particles that participate in strong nuclear interactions. A few brief notes on color charge:

  • Color is conserved in all interactions

  • All quarks have one of three colors: red, blue, and green

  • All anti-quarks have one of the opposite three colors: anti-red, anti-blue, and anti-green

  • Gluons have eight possible color charges (and one ninth theoretical charge that we've never observed). All of these are linear combinations of the typical quark and anti-quark charges, such as red-antiblue or red-antired + blue-antiblue

  • Different colors attract, like colors can't interact with each other

  • Only color-neutral particles can actually exist in stable states

The reason only color-neutral particles can exist is a bit complicated, but it has to do with symmetry. Essentially, any observable particles must be what are known as "color-singlets" (due to theory on symmetry and Lie Groups I won't get into here), which means that any color-swapping we perform on the gluons that make it up must result back in the same particle. Since we could do swapping such as Red <-> Blue or Blue <-> Green, any particle that shows any imbalance in color at all wouldn't be a singlet. This leaves only color-neutral combinations being allowed.

So, let's get down to how gluons and quarks interact, which gives us the fundamental nature of the strong nuclear force. The strong nuclear force has three possible vertices for interaction. The first and most important one happens when a quark goes along and emits a gluon. Since gluons must carry some color and color is conserved, this means that the quark must change color at the vertex. So for instance, we could start off with a red quark, which emits a red-antiblue gluon and becomes a blue quark. The other two vertices don't matter as much here, but for completeness sake, one of them is where a gluon emits another gluon, and the other is where two gluons directly interact (respectively, a vertex of three gluons and a vertex of four gluons).

Now, let's use this to try to put together a particle. First, let's start off with a baryon, which is made up of one red quark, one blue quark, and one green quark. A possible interaction here is for the red quark to emit a red-antiblue gluon and become blue, and then for the blue quark to absorb this gluon and become red. This leaves us with a color-neutral quark like we started with, so the interaction can and will occur, pulling the red and blue (now blue and red) quarks together. Of course, the third quark will also have to get pulled towards the other two to keep the baryon from splitting apart, so there will be interactions with it as well.

The other type of particle we can make is a meson, which consists of a quark bonded to an antiquark. For instance, let's say we start off with a red quark and an antired antiquark. The red quark can emit a red-antiblue gluon and become blue, and then the antired quark can absorb this gluon and become antiblue, leaving us with a blue-antiblue meson. This can then happen again, switching over to green-antigreen or back to red-antired.

However, there's a little quirk here. Red and antired don't actually cancel out with each other, and so don't actually qualify as color-neutral. So how is it that mesons exist at all? The trick here is that gluons undergo tons of these interactions and cycle through all the possible color combinations very rapidly. In fact, they can't really be described as oscillating but instead in a superposition of quantum states representing the possible color combinations. This means that at any given time, the "actual" color of a meson is red-antired + blue-antiblue + green-antigreen, and all of these do add up to neutral.

Before moving on to the weak force, there's one more quirk with the strong force I'd like to address: Why does it have limited range? Gluons, like photons, are massless and so have infinite lifetime, so why can't they travel out far?

The answer to this is complicated, but it starts with the fact that gluons also carry color charge, and since the second vertex which I mentioned briefly allows gluons to emit or absorb other gluons, then two gluons with different colors can attract each other. In general, you won't just have one gluon being exchanged between two quarks at a time; you'll have many. And all these gluons attract each other, compressing down into what's known as a "flux tube" between the two quarks. Any other gluons that are emitted will also be caught by this flux tube and will then travel over to the other quark.

The reason the electromagnetic force gets weaker with distance is that fewer photons emitted are going in the right direction to interact with the other particle (think of shooting a laser in a random direction with a target a close distance away. If you move farther from the target, its profile is smaller and you have a lower chance of hitting it). However, due to the effects of the flux tube, all gluons get pulled into the right direction so the number that interact doesn't decrease with distance, and the force stays the same.

So, shouldn't this imply that the force should be unbound rather than bound, if it doesn't decrease with distance? At first it seems so. The problem has to do with energy. Pulling quarks apart takes a ton of energy, and particles want to go to states with less energy. Eventually, you'll pull the two quarks so far apart that they'll find other quarks closer than each other and latch onto them instead (quarks only mate in pairs or triplets), emitting some energy and getting pulled in. Even if you had a perfect vaccuum, you're pumping a lot of energy into this pair by pulling them apart, and this is likely to result in pair production before long, giving two new quarks for each to attach to. So although the force could work at a large distance, it won't.

The Weak Nuclear Force

And finally, onto the last and most complicated of the fundamental forces. Part of its complication is that it further breaks down into two other types of interactions: Charged Weak interactions, which exchange a lot of properties between properties, and Weak Neutral interactions, which exchange only spin and momentum. Don't ask me about the adjective order; I didn't come up with it. Of these two, Weak Neutral interactions are a fair bit simpler and can sometimes actually act like a simple force, so I'll talk about them first.

Weak Neutral interactions are mediated by the Z boson, which is chargeless, high mass (so it decays rapidly and the force is short-range), and has a spin of 1. The allowed interactions are when a lepton or quark emits or absorbs a Z. The particle's type and charge are unchanged, but it gives some of its spin and momentum to the Z, which could then pass it on to another particle or decay into a particle-antiparticle pair.

This type of interaction is responsible for electron-neutrino scattering, which is where an electron and neutrino get deflected off of each other. Since neutrinos are chargeless, they can't be affected through the electromagnetic force, and since we do see this type of interaction in the lab, we know that Weak Neutral interactions are occuring.

And now, we get on to Charged Weak interactions. These interactions are mediated by W bosons, which are spin 1 and high mass like the Z, but unlike it have an electric charge of +1 or -1 and an isospin of +1 or -1 (respectively). As you may recall from my last post, isospin is a property that differentiates electrons from their neutrinos and the negatively-charged quarks from the positively charged ones.

The primary vertex for a Charged Weak interaction has some lepton or quark emitting or absorbing a W+ or W-. Since charge and isospin are conserved, this causes it to flip over to its counterpart in the same generation. For instance, an electron (charge -1, isospin -1/2) could come along and emit a W- (charge -1, isospin -1) and turn into an electron neutrino (charge 0, isospin +1/2). This W could then decay or it interact with another particle.

One common example of a Charged Weak interaction is Beta Decay, in which a neutron turns into a proton, an electron, and an electron-antineutrino. The neutron is made up of two Down quarks and an Up quark, while the proton is made up of one Down quark and two Up quarks. In the reaction, first, one of the neutron's Down quarks (charge -1/3, isospin -1/2) emits a W- (charge -1, isospin -1) and turns into an up quark (charge 2/3, isospin +1/2). Now we have a proton and a W-. Since the W- is unstable, it quickly decays. Its favored method of decay at these energies is into an electron (charge -1, isospin -1/2) and an electron-antineutrino (charge 0, isospin -1/2), so this is what we see happening. One simple variant on this reaction is that instead of an antineutrino coming out at the end, one comes into the system at the beginning and triggers the decay.

Now, you might be wondering how exactly this serves to work as a force (since it's grouped into the four fundamental forces). The simple answer is, it doesn't. Calling these "forces" is just bad terminology, and careful particle physicists use the term "interaction" to describe them all. It might seem weird that this never acts like a force, but let me remind you that the other interactions don't always act like forces either. For instance, in an electromagnetic interaction you can have an electron and a positron annihilate each other into a pair of photons. No forciness here, just a change in the types of particles. This is just the case for Charged Weak interactions, except Charged Weak ones don't have any options that leave the reactants and products unchanged.

So that's it for this overly-long answer to a question no one asked. If you have any questions on this or future questions you'd like me to address, leave a note in the comments.

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