Author Archives: mousomer

About mousomer

A philosophically literate mathematician with a couple of toddlers and a high tech job.

Biased, are we?

Intelligent systems and Racial bias – a couple of remarks

In, Rose Eveleth talks about the racial bias inherent in Facial Recognition systems. It is an interesting read. I would like, if I may, to make a couple of comments.


I must admit, first of all, that Rose Eveleth is correct. Face Detection and Facial Recognition systems suffer from racial bias. I have used many such systems, and they are all, always, racially biased. But I would just like to elaborate a little bit on that issue.

The underlying problem is simple – you need to train a system on a large “test set” of sample faces. Those “test sets” need to be generated by human beings, at a high cost. There are now two human biases coming into play:

Continue reading

On the manipulability of votes

This is the first installment in a series about social choice and welfare. The structure will be: historical anecdote, followed by “spoon-feeding” the conclusions.

Senate tribunal
Senate tribunal

So, here go:

We are in the 1st century A.C.. Pliny the younger is the current “chairman” of the Roman  Senate. And he is faced with a difficult situation. Consul Africius Dexter was found dead. Was he murdered? Was it an assisted suicide?
The freedmen who worked on his estate are sent to trial in Rome. The Senate is debating their doom.

The Senate gets divided into three groups. In the first and largest group, Pliny the younger convinces the other senators that there is no case for conviction. The death of Africius Dexter was a suicide, or very likely so, and the freedmen should be exempt from charge. The second group, slightly smaller, includes senators who are not willing to clear the freedmen from guilt. But they are not convinced enough to demand a harsh punishment. They opt for exiling the freedmen.
The smaller group, the third, is composed of senators who would have the freedmen all executed.

Most Senators expect Pliny the younger to count the votes on guilt, first, and then on punishment. The outcome in that case would be guilt, and the lesser punishment of exile, not death.

But Pliny refuses. He claims that coupling the options of exile and death and pitting them as a couple against acquittal is wrong. What do these punishments have in common, he asks? Surely, the distance between death and exile is larger than the distance between exile and acquittal. Pliny wants to count all three options as equal, and see what option would gain a simple majority. That is, which option has the larger pool of supporters.
This would mean, conveniently, that acquittal would win.

But that did not come to pass. The third group, the ones who want a death sentence, they “lie” and go over to the second group. Together, they have signed a majority for exiling the freedmen – much to the dismay of Pliny. As he moans in a letter to a friend, that was foul play.

Was it?

Why does -1 * -1 = +1 ?

I have been asked this by perplexed teachers, parents and kids:

Why did them silly mathematicians decide that the multiplication of two negative numbers is positive? What’s the logic?

The first thing is to acknowledge that this is a convention. We could define -1*-1 to be whatever we want. But there is good reason to decide it should be +1.

Let’s try to calculate:

-1 * ( 1 + -1)

Well, -1 is the negative of +1, which mean, by definition:

-1 + 1 = 0

So, -1 * (1+ -1) = -1 * 0

and multiplication by zero must be zero, so we have:

-1 * (1+ -1) = -1 * 0 = 0

But, if we open the parenthesis, we have:

-1 * (1 + -1) = -1*1 + -1*-1

now, multiplication by 1 is doing nothing, so -1*1 = -1, so we get:

-1 + -1*-1 = -1*1 + -1*-1 = -1*(1+ -1) = -1*0 = 0

hence, -1 is the negative of -1*-1, so the latter has to be +1.

What have we used? We used the definition of zero and 1, we used the definition of the negative of a number, and we used the law of distributivity (by which we can open the parenthesis).

We could decide, say, that -1*-1 = -1, but then we’d have to abandon one of the principles mentioned above, and that would make arithmetic rather unpleasant.

The hardships of equality

This post is an attempt to clarify and generalize the main points of:

and explain why equality is an excruciatingly hard goal. Note that equality is meant, first and foremost, to be formal equality in front of the law. I am not interested here in questions of economical equality, although extreme economic inequality often has legal and social repercussions.

What does it take to create equality?
Continue reading

On double and or

A small remark on programming conditionals. This is true for C and C++, but it might be true also for Java and other languages. I haven’t checked all of them.

It is about conditionals.

I’m seeing lots and lots of double OR and double AND in conditionals. In fact, I find it rare to see a single single operator these days. (Sorry, I couldn’t resist the pun). Almost without exception, every multiple conditional I see has the form:

if ((x>0) && (x<MAX_VAL))
   do something....

Which is kind of silly, really. The double operator && is the right thing to use when you have a complex conditional with function calls. But when all you do is compare arithmetical conditions? What one should do is use the simple single-operator

if ((x>0) & (x<MAX_VAL))
   do something....

Continue reading

Don’t compress it with that!

We had an issue at work. Our dev. team is managing a php server, which sends and receives binary KET files of constant size (say, 5kb) to production servers. I was rewriting some of the production servers and I notices that sometimes I’m getting TLE files in instead of KET files, and that they are 11 byte too big.

I checked it out. Apparently the dev. team was sending the KET files for compression (via php gzcompress). They were very much surprised to learn that the output files were larger than the original KETs. “Apparently”, they sighed, “gzip is not a very good compression. Let’s find another one”.

Which is the wrong conclusion. They have a meagre chance of finding a compression engine which wouldn’t expand the files. And this is a good excuse to explain this to the rest of the world.

An introduction to data compression

Mathematician’s digest:

Pigeon hole principle → no general compression scheme possible.

Range limitation → Data redundancy → range-specific compression possible.

Prima facie, compression is an impossible task.

Continue reading

What did go wrong?

A few years back, a friend bought me Bernard Lewis’ “What went wrong” and asked me for a review. This is somewhat late – but you might find it interesting.

Lewis’ starting points seem obvious: is the 13th century, Islam was the future. The Islamic centers in Mesopotamia were the peak of civilization. 700 years later, Islamic Mesopotamia is poor and sordid.
He is searching for an answer in culture. That seemed weird to me. Culturally, the east – and especially the Islamic east – was not a lethargic culture.
And I think I have a better explanation now.
Reading material:
Weatherford, Jack (2004). Genghis Khan and the Making of the Modern World (review). New York: Crown. ISBN 0-609-61062-7.

As people are the same, so are socioogical truths. It’s the same story in Israel, today, as well.



At the heart of the current debate about immigration are two issues: the first is about the facts of immigration, the second about public perception of immigration.

The facts are relatively straightforward. Immigration is a good and the idea that immigrants come to Britain to live off benefits laughable. Immigrants put more money into the economy than they take out and have negligible impact on jobs or wages. An independent report on the impact of immigration commissioned by the Home Office in 2003, looked at numerous international surveys and conducted its own study in Britain. ‘The perception that immigrants take away jobs from the existing population, or that immigrants depress the wages of existing workers’, it concluded, ‘do not find confirmation in the analysis of the data laid out in this report.’ More recent studies have suggested that immigration helps raise wages except at the bottom of the jobs ladder where…

View original post 1,879 more words

Microsoft: Some serious design mistakes

Beautiful, elegant

A nice keyboard

Ever so often I stumble across another annoying feature Microsoft is putting into their products. It never ceases to amaze me how creative the folks at Microsoft are at mis-designing products. Their products are always sleek, elegant, easy to use, and contain some hidden monstrosity under the folds.

At work, we have Microsoft Keyboards – just the most unbelievably hideous trap ever to be inflicted upon the unsuspecting world. The keyboard look nice enough, and is OK to use. Look at the picture. Notice those three little flat keys just between the ENTER and the numpad? Above the upper-arrow and below the “delete” key lurks a monster. Yes, it is a SHUTDOWN KEY! In the middle of the keyboard!

Need I tell you the details? You type a document, send out your little finger to press “up” or “del”, and all of a sudden the computer is shutting itself off.

And today I encountered another trap, at home. Here I am working at my computer (sometimes I still use MS windows, you see). And out of the blue pops a message. “Do you want to save?”. Well, why would I, in the middle of a messy revision? I press ESC, and the computer shuts down. Got me: It had an automatic update that was so much more important than my work…

So, shut down your automatic updates on Windows, double check MS products before you buy them, etc. All these advice work, but in my experience, they don’t work very well. remember: MS will always  have the upper hand. There’s always another snark hidden beneath the table, ready to jump at you when you least expect it.

Use Linux.

Simple rules to avoid Memory Leaks in C

Below are several short tips which will help you survive C programming. I’ll be adding and amending this from time to time.

The most terrifying aspect of the C programming language is closely related to it’s core strength. Programming in C is all about using pointers – which are memory locations. Thus, in C, when you need a variable to work with to store numbers and manipulate them, you don’t have to deal with the variable directly – you use it’s address, instead. This is, of course, a really stupid thing to do when you just have to use a single variable to store a single number. But it is an enormously useful strategy when sending that variable off to a distant procedure, or when dealing with large arrays.

Continue reading

Wikileaks, BBBGs and grand stupidities

The usual strategy in this Blog is to wait until the recent, important event is old and all public interest is lost, before I comment on it.

This is not because I abhor of readership, but because I feel that in order to say an intelligent thing about a subject, I need time to contemplate. This time I did the contemplation before it happened. So I am about to do my thing while the wikileaks scandal is still raging. Here are my 2 cents. And I will start with the sound-byte:

19 year-old boys are not adults. Give these boys weapons (the ultimate in big-boom-generating toys), train them to kill, and send them on to a conflict-ridden zone. Now, guess: what they will do there?

If you even imagine that they will do anything other than killing, then you’re a damn fool.

The army is not the problem. It is simply not the solution. You can’t expect a bunch of kids with big guns to build a nation state. Nor should you send them on to do serious police work. It is not their job, it is not their expertise. You train them to fight a war, send them out to face an enemy, and they find themselves in the middle of civilian population. Anyone seriously suggesting that no atrocities will ensue is either a god-damn lier, or pathologically stupid.

Let me repeat myself, at the risk of being crude:

An army is not a peace-keeping force. It is a fighting force.

Continue reading

One small in favor of Direct Democracy

I’m not quite sure that I like the idea of a direct democracy. But here is a small thought in favor:

Nancy Goldstein, down at the Washington Post, has a piece about the race for senate in Delaware, where she claims for the underdog. There are two candidates in Delaware. One seems like an experienced, rational, thoughtful, man. The other is a disgruntled, confused, and quite wacky, woman (But, no, this is not a gender issue!). Whom would you choose? Nancy Goldstein chooses the wacky girl, which is the one easier to identify with. The rational man is too arrogant. Too know-it-all. Most of all, he is not in need of your sympathy, so he doesn’t get it. Christine O’Donnell, the Tea Party candidate in Delaware, was more human – erring, confused, stressed. It stands in her favor in the debate, though the magic is less likely to actually help her win the race.

This is not new stuff. Those who know ancient Greek history should be reminded of Aristides and Themistocles. The others would do well to recall the surprising success of extreme politics throughout the 20th century. It should also remind you of what happens on shows like American Idol, where professionals have meager chance of winning. It is always the not-so-perfect girl-next-door who wins, seemingly “against all odds” – but very likely because she is not so annoyingly perfect. Or have a look at this fact: poll after poll shows that the Israeli public is mostly moderate, but abhors of moderate politicians. A majority wants good policy, but they want it delivered by flawed politicians.

So, if the public is much better at choosing policies than it is in choosing policy-makers, then perhaps, if we let the public choose the policies instead of the policy makers, we will enjoy better policies.

Atheism and the Mind II – Volitions and the abolition of souls

In the previous post I made the claim that atheists should not be any worse off than the religious when confronting serious philosophical questions. In this post I wish to show that they might be better off. I intend to show why the idea of an immaterial soul is misguided and needlessly confusing. I am going to use the example of volitions. And I warn you: This is not going to be an easy post to handle. If I succeed in writing anything intelligible , you are very likely to find yourself rather shaken.

I also wish to thank my dear friend Dr. Uri Maoz, who was the first to confront me with the following facts.

Here we go.

Continue reading

Atheism and the Mind – chapter 1

Over at The Road To God Knows Where, Brendano posits a challenge for atheists. He has a list of interesting questions to be answered. And I intend to step in on the line of duty, and try it out.

Brendano’s questions are, in order:

1. Why is the human mechanism better or more deserving of respect than any other mechanism … a lawnmower or a cat?
2. Whence do concepts such as human dignity, human rights, personal morality, right and wrong, good and evil arise, and what is their justification?
3. Why should anyone be held responsible for their actions, given that these are caused by chemical reactions in the brain, and chemicals have no sense of right and wrong?
4. Why do you have the concept of a quasi-separate ‘I’, as in ‘my body’, if you are just your body?
5. How can volition be anything other than an illusion?
6. Why should feelings, emotions, etc. have any importance if they are mere artefacts of chemical reactions?

I will answer in a different order, and I also intend to tamper with Brendano’s phrasing. Iam also afraid that this will take more than one post.

But first of all let me point out one huge and terrible blander, of which I hereby blame Brendano. He seems to think that these questions pose a difficulty for atheists alone. That is utter baloney. These are, and always have been, the greatest philosophical questions of all time, wrestled with by many religious thinkers. And if you think that any of these problems are even  remotely addressed by any conceivable religious dogma in existence, you are dead wrong. They certainly are not solved. Not through Christianity, Islam, Judaism, or any far-east religion in existence.

I short, then:

I do not know, but neither do you.

Continue reading

Atheism and Socialism


Should Atheists admire Monotheism, the same way Socialists love Capitalism?

When I first read Karl Marks’ The Communist Manifesto, I was very much surprised. I expected a demeaning rebuke of Capitalism, a scourge of fire scathing evil wealthy industrialists. But I found nothing of the sort. The Manifesto struck me as a paean for capitalism. It is full to the rim with the praise of capitalism. Marks and Angels are charmed with capitalism. There are a couple of (very big) issues which make capitalism the greatest peak of civilization (so far) in their eyes.

  • The first point is that capitalism has brought an age of limitless capability. Steam BoatsFrom their perspective in the middle of the 19th century, it is more than understandable. As they rightly exclaim, humans can now cross vast oceans in mere weeks. Fertilized crop yield vast amounts of food. For the first time ever, the medical establishment is doing more good than harm. Medicine actually works(!). And on and on. The list is endless. Capitalism has unleashed an enormous power. This power can do much good, and it does.
    Continue reading