"Why Open Source Misses the Point of Free Software" is stallman's definitive articulation of the philosophical divide between the free software movement he founded and the open source movement launched in 1998 by eric-raymond, bruce-perens, and the open-source-initiative. The essay exists in various forms; the version collected in free-software-free-society and on gnu.org represents the mature statement. It is the primary text for understanding software-freedom-vs-open-source as stallman frames it.
The essay acknowledges that free software and open source overlap substantially in practical terms: most open source software qualifies as free software and vice versa, and most of the same licenses are involved. The disagreement, stallman argues, is not primarily about which specific programs are included in each category, but about why the category matters.
The open source movement, as founded by eric-raymond, tim-oreilly, and bruce-perens, presented open development as a superior engineering methodology. By allowing many people to inspect and improve code, open source produces better, more secure, more reliable software. This is a pragmatic argument addressed to businesses and developers. It deliberately avoids claims about freedom, rights, or ethics, because those claims were seen as ideological baggage that made free software advocates harder to work with.
stallman's objection is that by removing the ethical argument, the open source movement abandons the only argument that justifies insisting on software freedom when it is technically inconvenient. If open source is just a development methodology, then a proprietary development process that produces better software in a particular case is a perfectly valid choice. If software freedom is an ethical requirement, then no engineering argument can override it, just as no efficiency argument can justify slavery.
The essay identifies the practical consequences of this difference. The open source movement is comfortable recommending and promoting non-free software that has "open source" characteristics for some components, or that is produced by an otherwise open-source-friendly company. The free-software-foundation insists on a clean line: non-free software is a social problem regardless of how it is produced or by whom.
The open-source-definition-schism of 1998 is the background event. stallman did not participate in founding the open-source-initiative and was not consulted. The split was deliberate: eric-raymond and others wanted to rebrand free software in terms that businesses would find acceptable, which required explicitly leaving behind stallman's ethical framework. stallman regards this as both strategically shortsighted and philosophically dishonest.
The essay does not question eric-raymond's motives or competence; it questions the consequences of the choice to present open source as a methodology rather than a movement for freedom. stallman's position is that the movement lost something irreplaceable when it traded ethical clarity for business acceptance.