Aim. Help students consider what information is and learn three distinct concepts:

• Life information: meaning formed inside a living system;

• Social information: signs/language unified with meaning in social contexts;

• Mechanical information: socially meaningful signs whose meaning has become latent—allowing copying, transmission, and computation.

In-class flow (slides).

• Brainstorm concrete examples of “information” and visualize with a word-cloud tool (e.g., Mentimeter).

• Experience the “typoglycemia” effect (scrambled text that still reads easily) and compare with an English sample; discuss why it feels readable.

• From these examples, discuss why information is inherently subjective rather than purely objective (silhouette illusions also work well).

• Introduce the three concepts:

  • The broadest is life information—meaning formed internally; in this sense information itself does not “transmit.”

  • Social information (life ⊃ social): communication feels like transmission when meaning is mutually understood (language, pictograms), but this is only as if.

  • Mechanical information (social ⊃ mechanical): when meaning becomes latent, we can mechanically copy and process it at high speed.

• Clarify that data quantity belongs to machine information: more data does not necessarily mean more meaning.

• Summarize the inclusion relation among the three concepts.

Notes. These ideas align with approved “Information I” textbooks (codes JI-703/JI-704) in Japan.