Tag Archive: Ranting

xckd hovertext

There is an excellent webcomic called xkcd. By excellent, I mean it is primarily for very nerdy math and science oriented people. It has the tendency to make very good points.

In addition to three new comics every week, if you hover your mouse over each one, a piece of text appears (much as when you hover over a file or folder, the name tends to appear). The hovertext is generally another joke, or an addition to the comic which makes it funnier, or makes another point. Something like that.

The most recent comic makes an astounding point about homeopathy. It reads:

“I just noticed CVS has started stocking homeopathic pills on the same shelves with–and labeled similarly to–their actual medicine. Telling someone who trusts you that you’re giving them medicine, when you know you’re not, because you want their money, isn’t just lying–it’s like an example you’d make up if you had to illustrate for a child why lying is wrong.”

Loathe as I am to say it, I hope someone dies while taking homeopathic medicine from CVS when actual medicine could have helped them, just so their blood will be on the hands of whoever thought this was ok.


Irreducible complexibullshit.

Irreducible complexity is fallacious. The argument of irreducibility must assume that evolution is false, and the conclusion it reaches is that evolution is false. You can always conclude your assumptions.

They say, “a cell is too complex to be the product of evolution. If it were, there would be simpler cells in existence.” There would not be. The simpler cells have DIED due to the fact that they did not become more complex. That’s what natural selection is.

It is mutation that has fostered evolution in the exact same way that a mutation has made me terminally ill. How’s that for some unintelligent design? But guess what? Natural selection works. I will not be having children. This genetic mutation will terminate in a leaf of my family tree. As all disadvantageous mutations eventually do.

One is not prime.

I was at trivia on Monday, with some friends from the department (the math department, that is). Our team consisted of six graduate students and above. As horrible as this may sound to some of you, believe me, mathematicians are AWESOME in groups.

We were winning (the questions were pretty easy, but I will admit to being mildly happy I knew a period of play in polo was called a chukker), when the following question came up: “What is the sum of the first five prime numbers?” We chuckled, more than a little. It’s 2+3+5+7+11=28.

After getting it right, and being in the minority, the teams who had gotten it wrong FREAKED OUT. “It’s 18! Everyone knows that!”

As I was wearing a shirt with a math joke on it (I often do), and as the host had noticed beforehand, she said, “where’s the mathematician I talked to before? What’s the answer?”

Calmly, I replied, “It’s 28. One is not prime. The first five primes are 2,3,5,7, and 11.”

Someone on an incorrect team said, “no, that’s not the standard definition. One is totally prime.”

Glossing over the fact that they used the word totally, I hope they got in a car accident on the way home I was irritated.

If you ignore this issue, much of mathematics works anyway. However, the Fundamental Theorem of Arithmetic, which I would say is one of the most critical facts in mathematics, needs 1 to not be prime. It says (essentially, for non-mathy readers) that the prime factorization of every number >1 is unique. The importance is clear: If this were not true, you wouldn’t be able to multiply numbers (the outcome would be unclear), so you wouldn’t be able to add, or divide, or subtract. Basically, standard mathematics couldn’t exist. But, because 6=2*3=1*2*3=1*1*1*1*1*2*3, 1 causes a failure of this (if prime) and so is not a prime number.

This is also discussed (generally, with a bit of historical context), on WikiPedia, for those further interested. It does say (and I agree) that you could allow one to be prime if you modified the statement (and the proof, which it doesn’t say) of the theorem. However, as mentioned, much of mathematics works this way; much is not all. You would need to modify many other things as well, some of which (trust the guy who’s taken algebraic number theory) get ugly.

I’m more interested in why people think one is prime. And I think I know why. It’s because it is (obviously, under either definition) not composite.

This is a problem I come across often when teaching, and it is the failure to understand logical opposites. Here are a few low-math, high-math, and non-math examples:

  • If a function is not even, that doesn’t make it odd. That means it fails the definition of an even function. Most functions are neither (a very select few are both).
  • If a set is not open, that doesn’t make it closed. There are plenty of sets which are neither (or both).
  • The opposite of “your mother” is not “your father”. It is “everyone other than your mother”.

In order for two things to be purely opposites, they need to form a partition of whatever universe they live in. That is, everything is one or the other, and nothing is both. For example, everything is either an “apple” or “not an apple”. Often we gloss over things with very small intersections, or which miss a few cases; we might say every human is “male” or “female”, and treat this (incorrectly, but with few exceptions) as a partition.

This is the problem. “Prime” and “comoposite” are not opposites. The partition of natural numbers consists of three sets: primes, composites, and {1}. There’s nothing at all wrong with that.

Toilet Seat Mathematics

The complaint you always hear is that men leave the toilet seat up, while women would prefer it be left down. Well, let’s crunch a few numbers to determine the total effort required by each party in the two cases. I’m going to ignore the lid in the following calculations:

With the seat up, men need to:

  1. Nothing.
  2. Lower it before, raise it after.

Women need to:

  1. Lower it before, raise it after.
  2. Lower it before, raise it after.

So the seat up yields a number of operations of 2 for men and 4 for women.

With the seat down, men need to:

  1. Raise it before, lower it after.
  2. Nothing.

Women need to:

  1. Nothing.
  2. Nothing.

So the seat down yields a number of operations of 2 for men and 0 for women.

The conclusion here is that, to men, it makes absolutely no difference whether the seat is left up or down, while women do less work with it down. The interpretation goes both ways: It could be viewed as selfish of women to want to do less work, or it could be viewed as selfish of men, as it makes no difference to them.

A second level of analysis makes the situation clearer. Considering that everyone (unless I’m strange) finds themselves in situation… uh… 1 more often than 2, if my meaning is carried, we find that men do more work with the seat down. Let’s go with a conservatively average estimate of three 1’s and a 2 each day. We find:

  • Seat up: Men have 2 operations each day, women have 8.
  • Seat down: Men have 6 operations each day, women have 0.

We now see the emergence of the complaint. Men do much less work with the seat up, Women do none with it down. As a unit, a couple does less work with the seat down. But the true conclusion here is that couples argue about this because people are greedy.

If the couple does indeed prefer the lid down, I’ll give the totals. The assumption I’ll make is that lifting both the lid and the seat together counts as one operation. A fair assumption.

  • Seat and lid up: Men have 2 operations each day, women have 8.
  • Seat down, lid up: Men have 6 operations each day, women have 0.
  • Seat and lid down: Men have 8 operations each day, women have 8.

The only conclusion we can definitively draw is that the toilet lid belongs up.

We could continue with an expected value calculation (assigning negative values to sitting on a closed lid, peeing on the seat or even the lid, or the infamous “falling in”), but we won’t. I’ll end this with a synopsis: The toilet lid should be up (at some point, even absent), and beyond that, I might say the seat should be left down for the greater good, but the argument exists for a reason.


It’s not a rational thing. I’m sitting in my car, listening to emo music, lights off, and have been for at least ten minutes. Well aware that it is dumb. Can’t motivate myself to go inside and go to bed. Sleep is an escape from the problems of the awake. I don’t really want to sleep problems off. Or be awake. I just want to not have problems. That last bit’s probably common.

My next post will be about math. Promise. Oh, 6/2*(1+2)=9. Learn what the order of operations means, don’t just memorize a mnemonic.


Over 1100 people have died in Haiti recently because of Cholera. Do you know what the cure for Cholera is? Fluids. WATER. We can send celebrities to Haiti to sing, but can’t send water. Are you going to lose sleep tonight about this?

…You probably should.

More Grading

I’m still grading these exams. I don’t get angry when my students are idiots, which many of them clearly are. If anything, it makes me sad. WE DID THIS.

You can train a monkey to repeat after you. Really. You don’t like math? Fine. You’re not going to need this? Fine. But if you can’t follow instructions and do something you’ve seen a few times, job training is going to be a bitch.


Do you remember what it was like to live without fear? I do. We were young. We were dumb. I miss that. Do you?


Going soon to have dinner with some friends, most of whom don’t know I’m sick. I’ll put on a happy face, tell my stories, my jokes. I’ve always been the funny guy. That has made it easy to hide what’s going on. To them I just walk funny.

I wonder if every one of my friends is hiding the way I am. I wonder if everybody is.

I gave an exam yesterday. Now I have around 480 pages of grading to do.  The students certainly don’t appreciate being told that they can’t duplicate what I’ve done for them several times. So why even do it?

It makes me wonder if there isn’t something else I should be doing with my time.