Code Simplicity

Privacy, Simplified

So, there’s a lot of talk on the Internet about privacy. Some people say that privacy is only desired by those who have something to hide. Some people insist that privacy is a human right that should never be violated without consent.

There’s only one problem with this whole debate: what is privacy, and why would anybody want it? This is rarely defined–most people just seem to assume that “everybody knows” that privacy is, so why would it have to be explained?

Well, I’m not a big fan of “everybody knows.” And in fact, it turns out that privacy actually means two different things, which many people use interchangeably without specifying what they’re actually talking about. So to help clear up some of the debate online, and to hopefully shed some light on how it can all be resolved, here are some clear definitions and discussions of what privacy is, and why people would want it.

Privacy of Space

The first type of privacy is “privacy of space”. This is the ability to control who does and does not enter a particular physical space, probably because you’re in the space and you don’t want certain others in that space. “Enter the space” in that definition includes any method of being able to perceive the space–so, for example, if somebody stands outside the door with their ear pressed to it, they’re violating your privacy. If somebody installs a camera in your room without your consent, they’re violating your privacy.

This form of privacy is not metaphorical. It does not apply to anything other than physical space. It literally means, “I do or do not want you to be perceiving this physical location, and I have the choice and ability to control that.”

The most common reason that we want this form of privacy is that we want to protect somebody or something from harm, most commonly ourselves. This harm can be minor (we don’t want to be annoyed by people walking through our house all the time), it can be purely social (we close the door when we go to the bathroom because we know others don’t want to perceive us going to the bathroom, and we may also not want to be perceived in such a state), or it can be extreme (a man with a mask and a chainsaw should not be in my closet).

One interesting thing about this form of privacy is that we don’t usually consider animals, plants, or material objects to be capable of violating it, even if they enter a space without our permission. It might be annoying if the cat comes in the room when you don’t want it to, but you’re not going to complain that the cat is “violating your privacy”, right?

So, when it comes to computer programs, this is not the form of privacy we’re talking about, since we don’t consider that a computer program being in the same room with us is a violation of our privacy of space. My word processor is not violating my physical privacy of space, even though it’s “in the room” with me, because it does not, itself, perceive. The only exception would be a computer program that was transmitting perceptions (sound or sight) to some location that we didn’t want to send it to–that would be a privacy violation, because someone could perceive our space through it when we didn’t want them to. When it comes to that sort of privacy, violations are pretty pretty cut-and-dry. If a computer program sends perceptions of my space anywhere without my permission, it is absolutely violating my privacy, it’s not useful to me, and it should stop immediately.

But on the Internet, that’s not usually the type of privacy we’re talking about.

Privacy of Information

The second type of privacy is “privacy of information.” This is the ability to control who knows certain things. When we talk about computer programs and the Internet, this is the most common type of privacy we’re talking about.

So why would somebody want privacy of information? Is it just because they’re doing something that they want to hide from others? Is it just for committing crimes or for hiding harmful acts? Well, sometimes it is, yes. There are many people who use the concept of “privacy” to protect themselves from the law or the moral rejection of others. It is probably because of these individuals that the concept of privacy is a muddy subject–as long as it’s unclear quite what “privacy” is, it’s much easier for those who have have committed harmful acts to invoke “privacy” as a defense.

But is that the only reason that somebody would want privacy of information? What about a normal person, who isn’t doing anything harmful–would they ever want to keep certain information private?

Well, there is absolutely a rational reason that people would want privacy of information, and interestingly, it’s the same reason that people want privacy of space:

An individual or group desires privacy of information because they believe that other people knowing that information could or would be more harmful than them not knowing it.

Here’s a very straightforward example: I consider that a criminal knowing my credit card number would be harmful–far more harmful than them not knowing it.

In certain countries, the fact that I read a certain website or talked to certain people on the Internet could get me killed or put in jail. So, in that situation, other people knowing my browser history could be very harmful, no question about it.

Of course, if one kept everything private, one could not live. If you pay for a piece of candy with a quarter, the person receiving that quarter now knows that you had a quarter. They may know that you kept it in a waller, or that you pulled it out of your pants. They probably know what you look like, if you’re not wearing a mask. They most likely also know that you have five fingers, and that you were in their store at a certain time. In short, no matter what you do, in order to live, you must exchange information with other people. The more things you do, the more information you will have to exchange.

In fact, usually, the more information that others know about you, the more helpful they can be. The bank knows all the transactions that I made, so they can help me by creating an online system that shows me my transactions and lets me search them. That information can be seen by bank employees, but I don’t consider that to be potentially harmful enough to outweigh the obvious benefits of the bank having it.

The web browsers that I use know my passwords to certain sites, so they can help me by putting those passwords into the box, saving me some typing. Potentially, somebody could steal that information from my computer, but the chance of that happening is small enough, and the benefit is significant enough, so I consider it acceptable to save my passwords in the browser.

The examples like this go on and on–the appropriate use of information is extremely beneficial. The inappropriate use is what’s harmful.

So who decides what what’s an appropriate use and what’s an inappropriate use? What information should be sent and stored, and what information should be kept private? Well, these are the fundamental questions being asked when people debate privacy issues–who gets to choose whether my knowledge becomes somebody else’s knowledge? Should I be asked before my information is sent, or should I just be given the option to opt-out and delete the information? Is there some information that should never be sent? What information is more important to keep private than other information?

Though this is all far less cut-and-dry than “privacy of space” issues, these questions can generally be answered by the “help vs harm” equation. The basic sort of questions one might want to ask would be:

  • Will sending and storing this information harm any users, immediately or potentially? (Remember, “potentially” is pretty broad–what happens if somebody with bad intentions steals that information from you? What happens if somebody buys your company and decides to use that information in a way that you think is bad?)
  • Would it help your users more than harm them to take this information?
  • Taking all the above into account, should sending this information be optional? (This is largely determined by how broadly it could be harmful to collect the information.)
  • If sending the information is optional, should it be opt-out or opt-in? (That is, should it automatically be on, and people have to turn it off if they don’t want to send the info, or should it be off and people have to choose to turn it on?)
  • If it’s opt-in, will the feature still be helpful to enough of your users to justify implementing it?

There are some people who will claim that no information should ever be sent or stored about the user, that all privacy options should always be opt-in, and that all information is so potentially harmful that no debate about this can be accepted. That is, frankly, a ridiculous proposition. It’s so obviously untrue that there’s almost no way to argue with it, because it’s such a shocking irrationality. Just like the fact that somehow, liquids could harm somebody (so you can’t bring liquids on an airplane in the USA) it’s true that there are situations in which almost any piece of information could be dangerous. That doesn’t mean that all information is dangerous, though.

My martial artist friends have frequently joked that they shouldn’t be allowed to bring any object on an airplane, because they could kill somebody with any of them. Similarly, given almost any piece of information, somebody could do something harmful with it, somewhere, at some point. If I know you have a quarter in your pocket, I’m sure there’s some situation in which I could use that information to get you in some serious trouble. But that doesn’t make that information realistically harmful, even potentially.

Even the idea of “every single piece of information should be opt-in” is ridiculous. Do you want the web browser to ask you, “May I send this page your IP address?” every time you load a web page? Well, if you’re a spy in a hostile country, maybe you do. But if you’re like most people, that would probably just annoy you–you’d stop using that web browser and switch to another one. And if you are a spy or a resistance fighter, then you probably know how to use Tor to avoid being tracked.

So when we’re talking about privacy, it’s not an issue of “in some incredibly unlikely situation, this information could be very harmful,” it’s an issue of balancing help vs. harm in real-world situations. Real-world situations can be pretty strange and unexpected, but they at least are real, and can be balanced and talked about. Doing so, you can make good decisions about how to protect your users’ privacy–how much information to take, how you inform them about the information you’re taking, and what you do with that information when you have it.

So no, this is not a casual issue or something that we should brush-off and just ignore the dangerous implications of, but it’s also not an extreme unsolvable situation where we have to decide to keep everything private because we can’t make up our minds about it. Privacy is simply something that we should be able to analyze factually, based on real-world situations and data, and come to some practical and useful decision about.


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