We are three-dimensional beings living in four-dimensional spacetime. While we can travel freely through space, we only experience a single moment of time: the specious present. Our perception only extends to this slice of the timeline as we are propelled forward through it. We remember the past with memory and simulate the future in our thoughts, but these instruments are entirely subjective. Our minds struggle with accurate time measurement and reliable data collection.


To address this limitation, we have developed various tools such as clocks and calendars.

Clocks point you to the present, the “you are here” sign for the fourth dimension. Calendars mark points of interest on the timeline. Alarms tell you when a future point of interest becomes the present.

These tools generally focus on the present and future, but our picture of the past remains fuzzy. If I ask you when your next doctor’s appointment is, you can look it up in a calendar instantly with minimal mental exertion. If I ask you how long it’s been since your last visit to the doctor, it will take more effort to answer. Maybe you can look up the date, but to answer the question of “how long has it been” will require another mental calculation on top of that.

Hindsight is an app I made for iPhone and Apple Watch that remembers past events and calculates time intervals.

By unburdening your mind from these calculations and making the information readily accessible, it gives you a new sense of awareness and perception of the past.

It helps you stay on top of anything that needs doing regularly, without requiring you to plan ahead.

Awareness can also be a powerful motivator for changing behaviour, to reign in vices or encourage good habits.

A histogram exposes patterns in the frequencies and intervals of occurrences to give you new insights at a glance. Alerts notify you when a certain amount of time has passed.

And being a timekeeping tool, of course you can access it from your wrist.

It’s a simple tool to make navigating the fourth dimension a little easier. I hope you find it useful like I do.

Hindsight is available on the App Store.