An Introduction to Privacy

Privacy describes how people should handle what they know about others. Why does this matter?

Knowledge is power: What you know enables you to do things you could not do otherwise. In particular, knowledge about people gives you power over those people: you can use it to influence how they think or act.
Knowledge is increasing: Every day, we all learn and do more things that others can then know about. Also, knowledge that may have been easily forgotten in the past can now easily persist.
Knowledge is fluid: People readily spread and receive it. We have always found ways to share knowledge with others, but recent technologies let us share it with far more people far more quickly than ever before.

Given all of this, what you do with what you know can create far-reaching effects. When that knowledge involves people, its impacts on them can also become far-reaching.

Example: When a friend tells you a secret, they may set an explicit norm of not telling anyone else.

When knowledge spreads, it carries the context of these impacts along with it, and that context leads to customs or limits on how others should handle the information. We can call these limits “norms.” For the people impacted, those norms reflect their expectations, agency, and interests.

Expectations: what you think or assume will happen when someone shares what they know about you.
Agency: what you want to happen, based on what you value.
Interests: what should happen in light of how it impacts you, even if you are not aware of particular risks.

Example: When a friend tells you a secret, they may set an explicit norm of not telling anyone else.

Example: If a stranger at a restaurant stared at you and took notes all through your meal, you would rightly feel unsettled. But when you visit a website, how do you even know if someone is “staring” at you?

If you record or share knowledge about people, respecting such norms protects those people from potential harms and supports them in pursuing their goals. But when a new technology changes how people record or share knowledge, it becomes less clear how to apply existing norms to the new situations created by those changes. That uncertainty can make people uncomfortable at first, and it can make the technology seem creepy.

Example: An 1890 essay on The Right to Privacy spoke to fears over a “modern device” of that era: the Kodak camera.

Over time, new technologies have kept arriving with greater speed. As they introduce more ways to record or share knowledge about people, they also raise more questions, such as if they still align with familiar norms. We have increasingly needed a better way to talk about how much these systems respect people’s expectations, agency, and interests when working with personal information. Eventually, that became the word privacy.

Example: An 1890 essay on The Right to Privacy spoke to fears over a “modern device” of that era: the Kodak camera.

How to handle information about people in a given context is ultimately a values-based decision that can depend on many competing interests. “Privacy” focuses on the perspective of people who are the subjects of that information.

(Last updated December 9, 2024.)