Earlier this year we saw articles published about the finding of an Earth-sized rogue planet in our galaxy. The way it was discovered is remarkable. A telescope was looking at a distant star, then the star seemingly brightened over a period of 42 minutes. And that was basically it.
When a massive object passes between a distant star and an Earth-based observer the light coming from the star gets deflected and focused by the gravity of the massive object. The star seemingly brightens as a result. This is called gravitational microlensing. The duration and how the brightening happens allowed scientists to determine that it was likely a Mars-sized planet and that it likely had no star within 8 astronomical units. It's likely a rogue planet of roughly Earth size.
Think about how little actual information these astronomers had. Yet they were able to make a very credible prediction on what happened. You see this all over in science, particularly in physics, where the truth is coaxed out of very little direct data. This makes me think that similar things can probably be done with data about people. This would mean that effectively anonymizing people's data is very hard or maybe even impossible.
Indeed, the ability to very accurately infer lots from very small amount of data is something I've long though of as the "Sherlock Holmes" problem. If there's just a few people with the ability to deduce lots of things, then they can be amusing and offer some limited utility, like Sherlock Holmes.
Computers are powerful enough though, and people clever enough, that everyone can now have a Sherlock Holmes in their pocket. And large corporations can have smarts far beyond Sherlock Holmes. So what once was a "eh, there's no rule against it, if you have the information the smart guy should be able to use it", is now a case of "oh dang, hmmm maybe civilization is built on the idea that not everyone is Sherlock Holmes."
Maybe this should have been my own blog post somewhere, but anyway, it's one of the many new conundrums of our time.
I think it's the same problem as surveillance. When tailing someone required a substantial investment of an actual person's time and a wiretap literally required physical handling of the physical lines to that person's phone, it makes/made sense to give the police wide leverage in who they put under a lens because it required a substantial investment of time from the police in a way that was intrinsically limited and unable to scale to the population level.
Enter today, when nearly everyone can be and is surveiled with detail cops of previous generation could only dream of, and we're still dealing with those same laws, but we removed the unwritten premises that they're based on: surveillance couldn't scale.
When a massive object passes between a distant star and an Earth-based observer the light coming from the star gets deflected and focused by the gravity of the massive object. The star seemingly brightens as a result. This is called gravitational microlensing. The duration and how the brightening happens allowed scientists to determine that it was likely a Mars-sized planet and that it likely had no star within 8 astronomical units. It's likely a rogue planet of roughly Earth size.
Think about how little actual information these astronomers had. Yet they were able to make a very credible prediction on what happened. You see this all over in science, particularly in physics, where the truth is coaxed out of very little direct data. This makes me think that similar things can probably be done with data about people. This would mean that effectively anonymizing people's data is very hard or maybe even impossible.