Editing The Free Software Definition (section)

==The Four Essential Freedoms of Free Software==
The definition published by the FSF in February 1986 had two points:<ref name="bull6" />

{{Blockquote|The word "free" in our name does not refer to price; it refers to freedom.  First, the freedom to copy a program and redistribute it to your neighbors, so that they can use it as well as you.  Second, the freedom to change a program, so that you can control it instead of it controlling you; for this, the source code must be made available to you.}}

In 1996, when the gnu.org website was launched, "free software" was defined referring to "three levels of freedom" by adding an explicit mention of the freedom to study the software (which could be read in the two-point definition as being part of the freedom to change the program).<ref>{{cite web |url=http://www.ru.j-npcs.org/usoft/WWW/www_gnu.org/philosophy/free-sw.html.en |title=What is Free Software? - GNU Project - Free Software Foundation (FSF) |publisher=Ru.j-npcs.org |date=1997-03-20 |access-date=2013-10-03 }}{{Dead link|date=February 2022 |bot=InternetArchiveBot |fix-attempted=yes }}</ref><ref>{{cite web|url=https://www.gnu.org/philosophy/free-sw.html.en |title=What is Free Software? - GNU Project - Free Software Foundation (FSF) |access-date=2013-10-03 |url-status=dead |archive-url=https://web.archive.org/web/19980126185518/https://www.gnu.org/philosophy/free-sw.html |archive-date=January 26, 1998 }}</ref>  Stallman later avoided the word "levels", saying that all of the freedoms are needed, so it is misleading to think in terms of levels{{cn|date=July 2024}}.

Finally, another freedom was added, to explicitly say that users should be able to run the program. The existing freedoms were already numbered one to three, but this freedom should come before the others, so it was added as "freedom zero".<ref>{{Cite web|url=https://www.gnu.org/philosophy/free-sw.html.en#f1|title=What is free software? - GNU Project - Free Software Foundation (Footnote)|author=Free Software Foundation|author-link=Free Software Foundation|quote="The reason they are numbered 0, 1, 2 and 3 is historical. Around 1990 there were three freedoms, numbered 1, 2 and 3. Then we realized that the freedom to run the program needed to be mentioned explicitly. It was clearly more basic than the other three, so it properly should precede them. Rather than renumber the others, we made it freedom 0."|date=2018-07-21}}</ref><ref>{{cite web|url=http://ma.tt/2014/01/four-freedoms/|title=The Four Freedoms|date=23 January 2014|quote=I [Matt Mullenweg] originally thought Stallman started counting with zero instead of one because he's a geek. He is, but that wasn't the reason. Freedoms one, two, and three came first, but later he wanted to add something to supersede all of them. So: freedom zero. The geekness is a happy accident.}}</ref>

The modern definition defines free software by whether or not the recipient has the following four freedoms:<ref>{{cite web
|url=https://www.gnu.org/philosophy/free-sw.html.en
|title=The Free Software Definition
|first=Richard
|last=Stallman
|publisher=Free Software Foundation
|access-date=2013-10-15
}}</ref>

{{quote|
*The freedom to run the program as you wish, for any purpose (freedom 0).
*The freedom to study how the program works, and change it so it does your computing as you wish (freedom 1). Access to the source code is a precondition for this. 
*The freedom to redistribute copies so you can help your neighbor (freedom 2).
*The freedom to distribute copies of your modified versions to others (freedom 3). By doing this you can give the whole community a chance to benefit from your changes. Access to the source code is a precondition for this.}}

Freedoms 1 and 3 require [[source code]] to be available because studying and modifying software without its source code is highly impractical.