One fair coin flip holds exactly one bit of information
Toss a fair coin and learning the result gives you precisely one bit, the amount of information that halves your uncertainty. Two tosses give two bits. That simple idea turns something as slippery as information into a quantity engineers can measure, compress and send around the planet.
At root, information is whatever has the power to inform. Any pattern that is not completely random carries some, whether it appears in a digital file of discrete symbols or in continuous forms like music, a painting or an electrical current. It is not the same as knowledge. Information is the meaning that can be drawn from a representation once someone interprets it, and extracting it amounts to resolving ambiguity.
It is often processed in layers. Letters inform words, words inform phrases, phrases inform sentences, until the reader arrives at knowledge in some domain; in a computer, bits become numbers and characters in the same stepwise way. Information theory measures how surprising an event is through the negative logarithm of its probability, so rarer events take more information to pin down. Redundant data can be squeezed only so far before hitting a theoretical compression limit. A 2011 article in Science estimated that by 2007, 97 percent of technologically stored information was already digital, and dated the start of the digital storage age to 2002, when digital capacity first overtook analogue.
The word has a surprising past. It came into English through Middle French, where it could mean a criminal investigation, from the Latin informatio, meaning conception or teaching. From the fourteenth century it referred to shaping the mind or character through instruction.
Its meaning then shifted with philosophy. The media scholar John Durham Peters traced how, as the medieval world gave way to modern empiricism, being informed changed from being given form to receiving reports. For thinkers like Hume, the senses delivered a swirl of fleeting impressions, and information drifted from the idea of an inner order toward the scattered raw material of sensation, from structure to stuff.
Source: Information
