In the post right before this one, I listed two different guiding principles that are commonly associated with education. First, there is education as scholarship. Second, there is education as a means to economic advantage.
My current take on education is that it's purpose is civic. Institutionalized education is supposed to train individuals to be good citizens. What counts as a good citizen in a democratic society? There are roughly three parts. First, a good citizen is informed, has beliefs about what constitutes a flourishing society, is able and willing to participate in reasoned debate with disagreeing individuals, is able to evaluate competing claims, is able to cogently articulate her views to others, and so forth. Second, a good citizen possesses the skills and the motivation to act on her ideas. This includes voting, participating in civic discourse, tasks related to her vocation, etc. Third, a good citizen has the desire and ability to act for the good of others, i.e. she has established a solid moral foundation.
This sort of view on education largely subsumes the other two views. Being an informed citizen requires that one be educated on matters of all sorts, including topics that may not be deemed "practical" for job purposes. Being an effective citizen requires that one possess the sorts of skills that largely overlap with skills that are pertinent to obtaining jobs.
Anyways, that's my brief take on the purpose of education. So where does philosophy fit in? It seems pretty obvious that philosophy plays a central role in developing the informed citizen. I tell my students that philosophy is the study of ideas. Philosophers examine the relationship between ideas and other ideas, as well as the relationship between ideas and the world the we observe, both physical and social. The philosophical method is simply the method of critical thought. If you are critically examining some claim, then you are doing philosophy. People trained in philosophy are, ideally, people equipped to critically examine options on display in the marketplace of ideas.