MIT licenses and other ones (BSD…) are free but are not “copyleft”. They don’t require all modified and extended versions of the program to be free software as well. Perhaps, that’s what you mean when you say “!= free”!
Note that all the source code in the public domain is free and not copyleft too so I agree with RMS when he defines copyleft software as a subset of all the existing free software (now and in the future, when all tends to become public domain).
In fact, GNU distinguishes more kind of slightly different free licenses:
Sorry for this long comment. My English is quite poor so probably some parts are difficult to understand. If someone wants clarifications of this clarifications, just say it and I’ll try again 😅
good explanation, I wouldn’t call your English poor :)
to put it another way: permissive non-copyleft free software licenses like MIT grant everyone the freedom to create derivative works which can deny other people freedom later, which is why predatory companies start salivating and rubbing their hands like OP’s man in the yellow jacket when they find high quality permissively-licensed code.
Exactly. To the evil company, it’s free. What’s not free is the rebranded software.
Free or libre?
Under the MIT license, a derivative work is allowed to be neither free nor libre.
A little clarification about the terminology I use: I use the term “free software” as RMS coined it (“free like in freedom”) and as GNU strictly defines on its website. They are some similar MIT licenses (the most common one is X11). Anyway they are very similar, free and GNU GPL compatible as you can read here: http://www.gnu.org/licenses/license-list.html#Expat http://www.gnu.org/licenses/license-list.html#X11License
MIT licenses and other ones (BSD…) are free but are not “copyleft”. They don’t require all modified and extended versions of the program to be free software as well. Perhaps, that’s what you mean when you say “!= free”!
Note that all the source code in the public domain is free and not copyleft too so I agree with RMS when he defines copyleft software as a subset of all the existing free software (now and in the future, when all tends to become public domain).
In fact, GNU distinguishes more kind of slightly different free licenses:
Note: free software != GPL compatible. EUPL 1.1 and 1.2 are free software but they are not compatible with GPL. http://www.gnu.org/licenses/license-list.html#EUPL-1.1
Sorry for this long comment. My English is quite poor so probably some parts are difficult to understand. If someone wants clarifications of this clarifications, just say it and I’ll try again 😅
good explanation, I wouldn’t call your English poor :)
to put it another way: permissive non-copyleft free software licenses like MIT grant everyone the freedom to create derivative works which can deny other people freedom later, which is why predatory companies start salivating and rubbing their hands like OP’s man in the yellow jacket when they find high quality permissively-licensed code.