# Information Theory: A Tutorial Introduction #### - James V. Stone **Link**: **DOI**: **Links**: **Tags**: **zotLink**: [zot](zotero://select/items/@stoneInformationTheoryTutorial) ###Abstract ``` ``` ### Notes-Highlights Indeed, Karl Friston’s free-energy theory 17;47 assumes that an organising principle for all behaviour consists of minimising the sum total of all future surprises (i.e. sensory entropy). ([Location 95247](https://readwise.io/to_kindle?action=open&asin=B07CBM8B3B&location=95247)) In order to know when to open and shut the door, the demon must use information about the speed and direction of each molecule. However, we already know that each bit of information cannot cost less than the Landauer limit of 0.693kT joules/bit (Equation 8.16). ([Location 86073](https://readwise.io/to_kindle?action=open&asin=B07CBM8B3B&location=86073)) We cannot get something for nothing, not even an observation.