Ideas Are Non-Rival Goods
In economics, there's a useful distinction: rival goods and non-rival goods.
For rival goods, consumption by one individual implies that another individual cannot make equal use of it.
Examples of rival goods include food, land, and most consumer goods. If Alice purchases a dozen eggs, those same eggs can't go to Bob's house. If Bob sits in seat 3F on the airplane, Alice can't sit in the same spot.
Non-rival goods, on the other hand, are not depleted through consumption.
Prime examples of non-rival goods include information and art. Other examples, up to a point, are public infrastructure and public spaces.
Alice getting to know today's news doesn't hinder Bob's ability to do the same. Alice's quiet enjoyment of a piece of music doesn't detract from Bob's enjoyment.
Gaining more knowledge doesn't detract from anyone else's ability to do the same.
Good ideas, especially when put to good use, multiply the experiential and material wealth in the world.
Ideas must be set free.