• Freedom 0: The freedom to run the program for any purpose.

• Freedom 1: The freedom to study how the program works, and change it to make it do what you wish.

• Freedom 2: The freedom to redistribute copies so you can help your neighbour.

• Freedom 3: The freedom to improve the program, and release your improvements (and modified versions in general) to the public, so that the whole community benefits.

The Idea being that once shared, the code will assist someone else — No need to Re-invent the Wheel.
I believe that, Knowledge is a Common Heritage of Mankind, and thus software, a form of knowledge, has to be free and accessible to all. And this en encumbers :
“There must be “ Open Distribution” and “Open Modification”

ALL TIME BIGGEST SOFTWARE REVOLUTION