Colourblindness and probability

A female acquaintance of mine was recently surprised to find that both of her sons were colourblind, despite neither parent being colourblind. A natural question to ask is ‘What are the odds?’ This question turns out to be open to interpretation, depending on what we mean by probability and odds.

Continue reading Colourblindness and probability

The police as the modern priest-Levite

Last weekend, I was cycling home at around 1am and was going through the East Road–Newmarket Road–Elizabeth Way roundabout, when I went past a woman who looked like she was waiting for a lift. However, the side of a major road away from any houses seemed like an odd place to wait for a lift, and she seemed distressed, so I stopped and asked if she was okay.

She was not okay. She was not waiting for a lift. She had been walking around Cambridge, lost, for the last two and a half hours. She was from a different city, having been on a hen night, having split off from the rest of the group, and trying to find her way back to the Travelodge. Her phone battery had run out. She was dressed up for going out; her shoes were not suitable for that much walking, and the cold weather was becoming increasingly unpleasant. (As it happened, the Travelodge was just down the road, about two minutes’ walk away.)

She was grateful, and told me that she had tried to stop and ask multiple people for directions, eliciting only ‘I don’t know, sorry’, rudeness, or abuse. Most horrifyingly, she had approached police officers for help and directions, but the police refused to help her, on the grounds that she was not a victim of a crime and therefore not in trouble.

Is their job to uphold the Law and to stop crime, or to serve the public and keep them safe?

Using Matrix instant messaging

Following my recent rant on decentralising our communications, I’ve started trying out the Matrix communication protocol on the suggestion of a friend. It’s a wonderful idea, and it’s great that the network can be connected to by various different clients. And it seems to be very easy to add people to the network: you just need to give their email address(*) to invite them. The is quite easy to use for basic usage, although there are some nuances that I haven’t got used to yet.

One thing that’s not immediately obvious is how you refer to things. On Twitter, you can refer to people as @jftsang and to groups as #example. On IRC networks, channels are usually called #channel or ##unofficialchannel.

Well, on Matrix, user IDs take the form @username:server, such as The latter part tells you about the homeserver of the user, which is needed because Matrix is a distributed network and different users might be accessing through different servers. Rooms take the form #room:server, and communities take the form +room:server. I’m not yet sure what the relationship between rooms and communities is.

(*) Ten years of relying almost exclusively on Facebook means that we tend not to have many of our friends’ email addresses. The situation was particularly bad when Facebook tried pushing their email addresses, which fortunately didn’t catch on.

I would recommend anyone interested in a free-as-in-speech-and-as-in-beer IM service to try this out; send me a message on on Matrix, or giving me your email address so that I may invite you.

Free speech and free beer

Facebook is in the news in both the UK and the USA for its dealings with Cambridge Analytica, in which Facebook users’ personal information was handed over to the political consultancy firm. There are a couple of problems with the way this is being reported in the media.

  • We, as mere users of Facebook, are not Facebook’s customers. We are its products. We refer to Facebook as a ‘service’ because we tend to think of it in much the same way as we think of the fire service, the armed forces or the NHS. But of these four things, only one of them is privately owned and largely unregulated.
  • This was not a data breach, it was a data leak if not a data transfer.
  • I haven’t read Facebook’s terms of use in any detail recently, but its almost certain that they permit this sort of data transfer to third parties (or at least does not specifically forbid them). It’s not a secret.
  • Even if it were a secret, it should be unsurprising. The selling of personal information is Facebook’s business model, which should be surprising to nobody. What do you think is paying for the upkeep costs of a website serving billions of people each day, doing so at zero price?
  • Although the #deletefacebook and #boycottfacebook campaigns are currently enjoying a surge in popularity and have the backing of prominent figures, they won’t result in immediate or significant change: I have said before that Facebook holds a monopoly on communication. This is exemplified by the fact that these campaigns are taking place, to a large extent, on Facebook.
  • Moreover, if we all migrate to a new social network (just as we have all left MySpace and Bebo), then the new company would be just as abusive towards its users. In any case, there is currently no centralised, zero-priced website that offers all of the things that Facebook offers its users: a soapbox, an address book, a calendar and an instant messaging service. Nor is there likely to be such a website in the future. This is a matter of economics; the ‘market’ for social networking websites admits natural monopolies.
  • As much as Brexit and Trump are regrettable, the fact that Cambridge Analytica was behind the two campaigns, helping to spread fake news and influencing the two votes to a strong degree, is a distraction. The real danger is our willingness to sign up to such a website in the first place.

For users of social networks, the only long-lasting solution is to break away from the centralised model and start using decentralised models, such as diaspora*. For instant messaging, using something like IRC would be a good first step towards decentralisation. As for having a soapbox, I run my own website (which you are reading now), because I want to have ownership and control over what I write. I have the freedom to amend or retract my content without the information being held in perpetuity by another party. I can make content accessible to a select group of friends without it also being accessible to any third parties (provided that I trust my friends, which by definition I do). Setting up one’s own website is not technically challenging, if one is happy to pay a monthly fee in exchange.

In summary,

‘Free as in beer’ implies ‘not free as in speech’.

That means you can’t expect to have a social network (or any other ‘service’) that does not charge you and yet entirely respects your digital rights.

On nonviolence and the alt-right

The actions of the driver at the Charlottesville alt-right rally, who killed one person and injured another nineteen, are indefensible. So too are the views of the alt-right in general. But everybody trying to oppose them must be very careful not to sink to their level and use their tactics.

One repulsive practice of the alt-right is doxing, the releasing of private or sensitive information about a victim. When a victim’s address is published, they may receive death threats or even actual attempts on their lives. The alt-right has rather systematically done this to public figures such as Anita Sarkeesian, as well as otherwise private individuals. It is disappointing to see some anti-fascists going through videos and photos from the Charlottesville rally and asking on Twitter for the people there to be identified and publicly shamed. There are at least two problems with this. Firstly, the Universal Declaration of Human Rights is very clear on this:

No one shall be subjected to arbitrary interference with his privacy, family, home or correspondence, nor to attacks upon his honour and reputation. Everyone has the right to the protection of the law against such interference or attacks.

‘Everyone’ includes people who hold abhorrent views, and simply attending a march – even a neo-Nazi one – is not justification for releasing somebody’s home address, work address or contact details. Secondly, identifying people from grainy photos is tricky and leaves room for plenty of false positives. There will be innocent people who look like someone at the rally, and who live nearby, who will be falsely identified as a Nazi, and shamed.

The same goes for physical aggression (which can be distinguished from self-defence in response to an attack). Of course punching somebody is far less serious than running them over, but that doesn’t make it easier to justify.

To be clear, the above is not a defence of the alt-right’s freedom of speech. Regardless of legal disputes over whether freedom of speech covers hate speech, it is a different matter as to whether violence against them is legal, morally defensible, or pragmatic.

On the other side of the Internet, other people can become dehumanised, and it is unsurprising that the hateful views of the alt-right have brewed over many years on the anonymised image boards of 4chan. But we must remember that:

When we oppose the alt-right, we must do our best to keep on the moral high ground.

Otherwise, we create a moral equivalence and help to justify Donald Trump’s notion that ‘both sides‘ are to blame.

In other words, violent actions such as doxing and assault are ineffectual even on a pragmatic level, even if you don’t believe in nonviolence as a moral absolute. And, just as we expect Donald Trump to disavow his hateful supporters, we should call out our own allies who do use these tactics. Their actions are as important as their words and their beliefs.

Political bias

The BBC and especially its political commentator Laura Kuenssberg have been accused of left-wing bias by right-wing people, and of right-wing bias by left-wing people. Many such people do not apply that criticism solely to the BBC, but also to many other media outlets that fail to agree with them. For example, Another Angry Voice repeatedly criticise what they call the ‘mainstream media’; they claim that their views are not adequately reflected by any broadcaster or newspaper, despite, supposedly, being very popular. Far-right groups have similar people, such as Alex Jones’ InfoWars.

But if it appears to you that everybody else is biased against you, then what is more likely — that your opinions aren’t all that popular, or that the editors of the BBC, the Daily Mail, the Times and the Guardian are in some joint, secret conspiracy to silence you?

Pride goeth before destruction, a haughty spirit before a fall.


  • Factual accuracy is not the same thing as being unbiased.
  • Misrepresentation of facts, particularly of statistics, does not count as factual accuracy.
  • To be clear, AAV and InfoWars are not simply left- and right-wing equivalents of each other. Despite both being biased, InfoWars does a lot more harm by actively promoting dangerous views such as the vaccine autism myth.

Anti-colonialism and Hong Kong democracy

Chris Patten gave an interview to the Guardian in which he described his regrets about not establishing sufficiently strong democratic institutions before the handover of Hong Kong in 1997, and criticised the anti-democratic positions of the Chinese government.

Some of the comments in response to that post call out the hypocrisy of a colonial governor calling for democracy, and point out the British Empire’s own poor record on democracy and human rights. While this may be true, it is a distraction: it doesn’t justify China’s actions.

If Western liberals are really concerned about democracy (as opposed to simple point-scoring against British colonialism and Conservative politicians like Boris Johnson and Chris Patten), then they must do more to speak up for Hong Kong’s right to vote, rather than keeping quiet and taking the ‘anti-imperialist’ view that this is an internal affair for China in which the West has no right to intervene. That would be echoing the propaganda machine of the PRC.

In defence of anecdotal evidence

Anecdotal evidence is worthless, right? It comes about through uncontrolled conditions, and the people reporting it may report selectively (whether or not they intend to be biased). Thanks in part to the works of writers such as Richard Dawkins, we have learnt to dismiss anecdotes and personal testimonials, bringing us closer towards a world governed by Reason and statistics. And we can consign anything supported merely by anecdotes to fire. Hurrah!

For many things in the natural world, it is relatively straightforward (if expensive) to isolate the thing to be tested, conduct experiments or controlled trials, and then quantify the effect of that thing, with well-defined error bars. There are well-established principles and procedures for designing clinical trials, which is why we can resolutely label things like homeopathy, claims about the MMR vaccine, and everything Deepak Chopra says as bullshit, even if there are occasional success stories.

But – and perhaps Dawkins and co. haven’t realised this yet – humans are complicated, and social phenomena, which involve multiple humans, are very complicated. It is impossible to control the environment in which they arise. Also, individual experiences are unique, and it is difficult to give meaningful definitions or boundaries (see also this post), and to ensure that everybody uses the same definition. Related to this, people do not always accurately report their experiences: something that is perceived to be ‘shameful’ will be underreported even if it is actually quite common.

For these reasons, many social phenomena have not been studied quantitatively. But

Absence of evidence is not evidence of absence.

If anything, it is evidence that you haven’t yet done a good enough job collecting evidence on the subject.

When nothing else is available, and when it is not possible to conduct a systematic, controlled and quantitative study, then anecdotal evidence is the best you can do, and it needs to be taken into account, provided it comes from a credible reporter, who has no vested interests. And you must hear that evidence, even if you do not give it much weight.

In more technical language, I am arguing that probabilities are subjective measures of a degree of belief, not objective, and that any evidence should update your posterior probability, even if not by very much.

What I’ve said so far has been relatively abstract, but a failure to understand this has truly harmful effects when we dismiss anecdotal evidence. When hundreds of people report that they have been victims of something, then we need to start taking their testimonials seriously.

The Everyday Sexism Project has collected reports from tens of thousands of women about the sexist abuses that they have suffered. These are idiosyncratic and can’t be categorised; they might have happened repeatedly over a long time, or be one-off events. These acts are often not visible: even the person doing or saying the sexist things might not realise that they are being hostile. An individual claim of sexism might be dismissed by suggesting a variety of mitigating circumstances, or even by assuming bad faith on the part of the reporter! But what is more likely: that misogyny exists in our society, or that thousands of women have conspired together to make up that myth? (You may find Occam’s razor useful.)

Everyday sexism is just one example of microaggression, which also happens in other contexts such as race and religion. Moreover the fear of being subject to a racist attack is just as relevant as the number of actual attacks. Fear has a chilling effect on society, and has a measurable effect on the economy, but by its very nature it is difficult to measure.

Other examples include people’s testimonials of an NHS (or other public service) that is unable to provide a good experience. When thousands of people across the country complain about this, then it is no longer an egotistic individual or a problematic local service; there is something nationwide happening.

In summary,

When thousands of anecdotes are given, then it is no longer "merely" anecdotal evidence.

As with the etymological fallacy, the failure to give anecdotal evidence the weight that it sometimes deserves is a dangerous fallacy, because it is easy to commit it, thinking that you are rational and your opponent is not. This arrogant attitude poisons a discussion.