Stallman wrote that programmers who share Torvalds' view "want the freedom to lock down computer users. They want the freedom to impose DRM. [But] if your concern is computer users, then you see that at the most fundamental level freedom has to be put in the hands of the least empowered user by putting in place a system that ensures that even without computer skills they can effectively have the freedom that the more powerful members of the community have."
But, just to complicate things, the distinction is not just between the pragmatism of open source and the idealism of free software. Although the fact is easy to overlook, open source can be just as idealistic in its way as free software. The idea that code is better when it is shared is a re-statement of the ideal of academic freedom and the free exchange of information.
Richard Stallman and the Connotations of Language
GNU/Linux Desktop: The Case Against Running Windows Apps
How the GNU/Linux Community Ranks Distros
Interview with Richard Stallman: Four Essential Freedoms
You can even argue, as Torvalds does, that concern for your own access to code as a programmer is a case of enlightened self-interest. "It's about 'empowering everybody' by letting some enterprising users empower themselves, and then taking advantage of it for everybody else," he told me last August. From this perspective, empowering developers and empowering all users are goals that "are not at odds at all."
From this perspective, the most accurate description of the difference implied by "free" and "open source" is one of conflicting ideals -- or, perhaps, of an argument over the means to the same goal or the priorities. While open source supporters like Torvald argue that empowering developers ultimately empowers everyone, free software advocates like Stallman insist that what is needed is the extension and protection of user's rights in their own computers and software. Both are also convinced that the other's view is likely to lead to disaster.
You might feel, especially at first, that the controversy is one of trivialities. And, to a degree, you would be right. Members of the free and open source software communities have far more in common with each other than not. The communities overlap, and generally use the same software and the same licenses. Yet every now and then, some issue -- most recently, last year's discussion around the changes in the third version of the GNU General Public License, portions of which are quoted above -- reminds everyone that the underlying differences can be profound.
Yet, even when the difference is not on everybody's mind, it still exists, so you need to be careful of it.
On the one hand, if you do more reading and decide that your ideals align with one side's in the third sense of the definition given here, you may choose to use that side's terminology. That is why, left to myself, I tend to refer to free software, using "open source" only in direct quotes.
On the other hand, if you feel confident that you understand the difference, you might alternate the terms, referring to free software when talking to those for whom the community and user empowerment is most important, and to open source when referring to those for whom business and shared code is most important.
The trouble is, judging when to use each term can be difficult. Nor can you always count on listeners to understand the distinction you intend. Often, too, you may not want to stir up the old controversy again. For any of these reasons, you might prefer a more diplomatic term.
Eben Moglen's preference for "the free world" has wry connotations of the Cold War, and is immediately obvious in context. However, the more widely used alternatives are "free and open source software" (FOSS for short), or "free/libre and open source software" (FLOSS), which has the advantage of explaining what sense of "free" you have in mind.
Of the two, FOSS seems to most common these day. But the advantage of both FOSS and FLOSS is that they are generally accepted by both camps. By using either acronym, you can avoid the distraction of semantics and get on with your real business without alienating anyone by accident.