Claude Shannon separated information from meaning

Gleick presents Claude Shannon's 1948 paper "A Mathematical Theory of Communication" as the pivotal moment when information stopped being a vague, intuitive concept and became a precisely measurable quantity, defined in terms of probability and uncertainty rather than content or meaning. Shannon's insight was that the amount of information in a message depends on how surprising or unpredictable it is, not on what it actually says — a highly predictable message carries little information, regardless of its importance to a reader.

This separation let engineers measure and optimize the transmission of information across noisy channels, from telephone lines to computer networks, without needing to interpret what the message meant, which turned out to be the key breakthrough enabling reliable digital communication.

Gleick treats this as one of the most consequential and underappreciated intellectual achievements of the 20th century, since it created a universal unit — the bit — that could describe communication in radically different systems.

Takeaway: how much information something carries is a matter of surprise and probability, not significance.