No one knows where the ancient Greek aphorism “Know Thyself” originated — it has been ascribed to Socrates, Pythagoras, Heraclitus and a host of other philosophers. The phrase, most famously engraved in the forecourt of the Temple of Apollo at Delphi, forms the basis of many of today’s most practical and productive life-hacks, the tools we use to be better people with better lives.

Think of Weight Watchers, with its food journals. Think of bankruptcy trustees, who help bankrupt people by requiring them to keep spending journals. Think of the pedometer on your belt. Or think of Cognitive Behavior Therapy, in which you think yourself free of depression by keeping careful records of the deeds and events that bring you low, and use that journal to understand when your mind is blowing reality out of proportion.

Our computers are full of small pieces of “myware” — software that spies on you for your own benefit, helping you to know yourself better. Your browser’s History file autocompletes the URLs you type into the location bar; the search box remembers your previous searches. The recent-documents list in your word processor, your email program’s capacity to remember the people you’ve emailed before — all little bits of useful mental prosthesis, external systems that help you keep track of what you do, so that you can do it better.

But “Know Thyself” has an ugly, sinister cousin: “Know Thy Neighbor.” This is the curtain-twitching philosophy that drives us to spy on the people around us (sometimes at the behest of the government, who appear to have learned nothing from failed snitch states like East Germany). It’s the folly that drives merchants, bosses and governments to watch us through a million CCTV cameras, track us through spyware that keeps track of what we install on our PCs, follow us around the Web with beacons, count our keystrokes, and log our library books.

I think it probably starts with Taylorism and “scientific management” — the kind of thing that features so entertainingly in Frank Bunker Gilbreth, Jr. and Ernestine Gilbreth Carey’s 1946 memoir “Cheaper by the Dozen,” about their parents Frank Bunker Gilbreth and Lillian Moller Gilbreth, and the early days of time-motion study.

The Gilbreths invented everything from touch-typing to surgical procedure by recording workers’ movements using sensitive instruments and then analyzing them in detail, discovering inefficiencies that could be engineered out of the system. This kind of surveillance is a kind of liminal case between spyware and myware: there’s an element of coercion to it (the worker who screws together an assembly “inefficiently” may not want to be “corrected” — perhaps the little inefficiencies are how he finds a moment to daydream or express a shred of autonomy while operating as a cog in the machine). But at the end of the day, these proto-ergonomists were interested in helping the people they recorded to work better, save time and motion, to avoid injury and mistakes.

But for an eye to be both all-seeing and all-benevolent is asking a little much. The temptation to spy on your employees’ email, to watch your customers’ behavior, to track readers as they move around the web is enormous. And once such a system is created, it cries out to be abused.

Take the example of the Irish bureaucrats who raided the national identity registry to look up juicy facts about celebrities and to find blackmail dope on people they didn’t like very much. The aberrant thing about this case is that the crooks were caught — but not that they were raiding the database in the first place. Private eyes have had friendly cops who’d look up driver’s license information for them for decades. It’s hard to believe that all the folks sitting on top of Amazon, Google, iTunes and the other giant databases of personal info are any less inclined to snoop and bend the rules than the police are.