What are topological defects?

This is a repost of an article I wrote in 2013, back when I was willing to take the time to explain physics stuff, and generate lots of images too.

Donut and Coffee
(image source)

It’s often said that topology is the branch of mathematics where they can’t tell the difference between a donut and a coffee mug. They each have a single hole (the mug’s handle and the donut hole), and that’s all that matters. If I may overanalyze this joke, the point seems to be that topology is so disconnected from our everyday experience. How is this useful?

I wish to explain one particular use of topology in physics: topological defects.

A topological defect is a sort of knot that exists in the microscopic structure of a material.* You can move the knot around from atom to atom, but you can’t untie it. We’ll get into how that works soon enough.

*Material is a vague term for “stuff”. Later I’ll discuss a few different materials including magnets, liquid crystals, and superconductors [Read more…]

Re: Necessity of sex-positivity

Fellow FTB blogger Great American Satan wrote a post called Sex Positivity: Still Necessary, which defends sex-positivity against asexual discourse.  This is a response from an asexual perspective.

First, some general comments:

  • I consider myself sex-positive.  However, because I participate in the ace community, non-sex-positive, or sex-negative views are within my Overton window.  I will offer some defenses of these views, but I ultimately agree with the thesis that sex positivity is still necessary.
  • If you read the comments on GAS’s post, there are a few from Elizabeth Leuw.  I will say basically the same things she does, but with fewer links.  This does not necessarily reflect a consensus view, it’s just that Elizabeth and I are on similar wavelengths.  She is one of my cobloggers on The Asexual Agenda.

Sex positivity in principle and practice

The central problem with sex-positivity is its supporters.  If you meet several sex-positive people, and all of them advocate for harmful messages (e.g. everyone should enjoy sex; no one should ever be grossed out by sex; more sexual content in the public sphere is necessarily better in the long run), you might reasonably disidentify with sex-positivity.  You might like sex-positivity in principle, but dislike in practice, and what it is in practice is important.  Or perhaps you think that the roots of its problems lie within its principles.

I will point out that this is not so different from the way many FTB readers disidentify with the skeptical or atheist movements.  You could decide that Richard Dawkins, Sam Harris, and DJ Grothe are so bad that you want no part.  Or you could decide that you want to stay involved. [Read more…]

How to argue

Correct argumentation is obviously a very broad topic, and I cannot hope to present any sort of ultimate guide on it. My goal here is more humble: to present principles that I personally have found useful, especially in the context of arguing on blogs and in the comments. This was initially an update of something I wrote in 2014, but I ended up rewriting the whole thing.

If you’d like to see any particular point expanded out, please express your interest!

1. Identifying Goals

90% of everything is crap, and that goes for arguments too. It is worth considering what you want in an argument, and whether the argument in front of you fulfills your purpose. Arguments that do not fulfill your purposes should be dropped. You could be spending that time on more productive arguments, or for that matter playing video games.

Truth vs Power

Some arguments are about finding truth, and others are about acquiring power.

Truth is the same for everyone, so truth-seeking arguments should in principle be cooperative. You don’t want to win every truth-seeking argument, you only want to win the ones where you started on the correct side. Being good at arguing means being good at losing arguments when you are wrong.

Power-seeking arguments, on the other hand, are competitive. The winner of such an argument usually gains legitimacy, or perhaps decision-making power. Since few people willingly give up power, these kinds of arguments rarely result in any participants being convinced.

Most of this post addresses truth-seeking arguments rather than power-seeking ones.
[Read more…]

On voting strategy

In a voting system like we have in the US (“plurality voting”), we may apply something called the median voter theorem. The median voter theorem says that in a face-off between two candidates, the candidate closer to the median voter wins. Here we’re assuming a one-dimensional preference scale (e.g. left to right) and that voters choose the candidate who is closest to them on the scale. The winning strategy for each candidate is to move closer to the median until they are nearly indistinguishable, and each has about 50% of the vote.

As a result, you can see many politicians shifting their views over time, carefully tracking the median view. In the US, voters seem to be uncomfortable with this optimal strategy, and thus they demand that politicians put on a show of having believed in their current views all along. And then when politicians visibly contradict their previous views it’s used as a gotcha. This is incredibly tedious.

Of course, it does not really seem like the major candidates follow the median. Trump and Clinton, are, after all, very far apart! In fact, I’m puzzled why US presidential elections don’t hew more closely to the median voter theorem. I imagine this is a subject of study for political scientists, but I only have baseless speculation to offer. And of course I’m ultimately trying to say something about the current election cycle.
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No causal comparison

cn: sexual assault and victim blaming are discussed briefly as an example.

Often we observe some phenomena or trend, and we wish to explain what caused it. Different people can disagree on the cause. Or perhaps they agree on the causes, but disagree on which causes are important. Bold claim: There is no objective way to assess the relative importance of two causes.

I’m making a purely abstract argument, but I’ll offer a few provocative examples:

1. Is a given human trait caused by genetics, or the environment?

2. Is personal success caused by hard work, or by lucky circumstance?

3. Is terrorism caused by politics, or by religion?

4. If a woman is victim of sexual assault, is that caused by the perpetrator, or by risky behaviors on her part?

5. Is our knowledge of physics the result of scientific research, or is it the result of the continuing absence of an earth-destroying supernova?

Among these examples, we’d obviously like to say that some causes are more important than others. We are welcome to say so, but there is necessarily an element of subjectivity in our words.
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Linkspam: June 4th, 2016

Did you know that FTB is still accepting applicants?  Apply by June 16th!  This page has information about who you should contact and what information you should provide.

And now for my monthly linkspam.

When a Negative Statement Becomes a Claim – Crys talks about an argument she had about whether bisexuals exist.  She argues that the negative statement (bisexuals don’t exist) is the one with the burden of proof here.  As I said in the comments, skeptics/atheists have a tendency to deny personal experiences on the grounds that they’re not science.  But if you look at actual scientific research on sexual orientation, researchers mostly just ask people for their personal experiences.  Skeptics, you’re doing it wrong.

Identities formed by trauma are still valid – Gosh, this is a really major topic among aces, because traumatic experiences with sexual abuse are after all quite common.  Some aces feel that trauma might have caused them to be asexual, or it might have impacted their sexuality in other ways.  Some aces simply don’t know how trauma impacted them, and will never know.  Aces with trauma are put in a precarious position, where many people question the validity of their identity, and the ace community itself will gloss over their existence.

Anyway, you can read all about this in Miri Mogilevsky’s article.  There are also many personal experiences out there, but I wouldn’t link them, since privacy is a serious issue.  If this subject is of personal importance to you, you can find things in my blogroll.

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Origami: Reverse square tessellation

IMG_0863 (small)

Reverse Square Tessellation, a model by yours truly.

Most of the origami I do is modular origami, but I dabble in other branches of origami too.  This here is an origami tessellation, a folded pattern that could hypothetically repeat infinitely in the plane.  I’ve made a few tessellations by origamist Eric Gjerde, but this here is an original.  Further photos below the cut.

[Read more…]