UK science fiction writer Charles Stross, author of novels Accelerando and Singularity Sky, posits a future in which all human experience is record on devices the size of a grain of sand.
We've had agriculture for about 12,000 years, towns for eight to 10,000 years, and writing for about 5,000 years. But we're still living in the dark ages leading up to the dawn of history.
Don't we have history already, you ask? Well actually, we don't. We know much less about our ancestors than our descendants will know about us.
Indeed, we've acquired bad behavioural habits - because we're used to forgetting things over time. In fact, collectively we're on the edge of losing the ability to forget.
For the past 50 years we've become used to computers getting cheaper and more powerful exponentially - doubling in performance (or halving in price) roughly every 18 months.
The core trend, described by Intel co-founder Gordon Moore, describes the transistor count in microchips.
But a parallel trend in data storage means that storage space is becoming twice as plentiful on a similar time scale - and our ability to generate data to store is also increasing, as witness the 4m CCTV cameras around the UK, and about 70m cellphone accounts, of which maybe half are associated with camera phones able to record video.
Sooner or later they're all going to be switched on, all the time and our data storage capacity is growing so fast that we need not delete anything ever again.
There are huge legal, ethical, and privacy issues connected with recording this much information, never mind sharing it; as security expert Bruce Schneier has said: "... managing data privacy is going to be the big legal problem of the 21st century".
But I'm assuming, for the sake of argument, that we will find answers or compromise solutions to these questions. We'd better, because those cameras aren't going to stop recording and go away.
How far can it go?
Moore's law has an end in sight, dictated by physics. We can't build circuits out of components smaller than atoms.
But we can envisage building data storage devices that use individual atoms to represent one bit of information.
Consider a carbon crystal, created (and edited) one atom at a time by nanomachinery; there are two stable isotopes of carbon, and we can use a Carbon-12 atom to represent a binary 0 and a Carbon-13 atom to represent a binary 1.
One gram of this substance could store 10 to the power 21 bytes (887,808 petabytes) - the equivalent storage of more than 11 billion typical PCs.
By way of comparison, in 2003 we as a species recorded 2,200 petabytes (2.5 x 10 to the power 18 bytes) of data - enough to fill the hard drives of more than 28m typical PCs.
If we can figure out how to read and write data on the atomic scale, you could store the sum total of all the data we recorded in 2003 on a grain of sand.
We're only a few years away from the cost of data storage dropping so far that we can record "everything" that happens to us: our location at any given time, what we are hearing, what we are seeing, and what we are saying or doing.
The storage requirement for a video stream and two audio streams, plus GPS location, is only about 10,000 Gb per year - which will cost about £10 by 2017.
With your phone converting all the speech it hears to text (and storing that, too, and indexing it by time and location it becomes possible to search it all - like having Google for your memory.
You don't ever need to forget a conversation again, even if all you can recall about it is that it was with a stranger you met in a given pub about two months ago and someone mentioned the word "fishhooks".
If you're a police officer, it means never forgetting a face and always logging all your interactions with the public.
If you're suffering from the early stages of dementia, or if you're simply over-worked and expected to keep track of too many tasks at the office, it means you've got a memory prosthesis to help you keep track of things.
And if you're a student, it means you can concentrate on understanding your lecturer, and worry about making notes later.
This technology is available now -- some researchers are using it - in a few years' time, it's going to be as cheap as owning a mobile phone, and a few years later it'll be just an extra feature of your mobile phone.
It sounds strange right now, but there are too many uses for it to remain an eccentric niche. In the long term, almost all human experiences will be recorded. And in the very long term, they'll be a gold mine for historians.
Using nanoscale diamond as data storage, six hundred grams (about one and a quarter pounds, if you're my generation) can store a lifelog, a video and audio channel, with running transcript and search index, for six billion human beings for one year.
Sixty to a hundred kilograms is all it takes to store an entire 21st Century of human experience.
And some time after our demise, this information will be available to historians.
And what a mass of information it will be. For the first time ever, they'll be able to know who was where, when, and what they said; just what words were exchanged in smoky beer halls 30 years before the revolutions that haven't happened yet: who it was who claimed to be there when they founded the Party (but didn't join until years later): and where the bodies are buried.
They'll be able to see the ephemera of public life and understand the minutiae of domestic life; information that is usually omitted from the historical record because the recorders at the time deemed it insignificant, but which may be of vital interest in centuries to come.
For the first time ever, the human species will have an accurate and unblinking, unvarnished view of its own past as far back as the dark ages of the first decade of the 21st Century, when recorded history "really" began.