The best part of the rise of online education is that it forces us to ask: What is a university for?

Are universities mostly sorting devices to separate smart and hard-working high school students from their less-able fellows so that employers can more easily identify them? Are universities factories for the dissemination of job skills? Are universities mostly boot camps for adulthood, where young people learn how to drink moderately, fornicate meaningfully and hand things in on time?

My own stab at an answer would be that universities are places where young people acquire two sorts of knowledge, what the philosopher Michael Oakeshott called technical knowledge and practical knowledge. Technical knowledge is the sort of knowledge you need to understand a task the statistical knowledge you need to understand what market researchers do, the biological knowledge you need to grasp the basics of what nurses do.

Technical knowledge is like the recipes in a cookbook. It is formulas telling you roughly what is to be done. It is reducible to rules and directions. It's the sort of knowledge that can be captured in lectures and bullet points and memorized by rote.

Right now, online and hybrid offerings seem to be as good as standard lectures at transmitting this kind of knowledge, and, in the years ahead, they are bound to get better and more imaginatively curated, more interactive and with better assessments.

The problem is that as online education becomes more pervasive, universities can no longer primarily be in the business of transmitting technical knowledge. Online offerings from distant, star professors will just be too efficient. As Ben Nelson of Minerva University points out, a school cannot charge students $40,000 and then turn around and offer them online courses that they can get free or nearly free. That business model simply does not work. There will be no such thing as a MOOC university.

Nelson believes that universities will end up effectively telling students: Take the following online courses over the summer or over a certain period, and then, when you're done, you will come to campus and that's when our job will begin. If Nelson is right, then universities in the future will spend much less time transmitting technical knowledge and much more time transmitting practical knowledge.

Practical knowledge is not about what you do, but how you do it. It is the wisdom a great chef possesses that cannot be found in recipe books. Practical knowledge is not the sort of knowledge that can be taught and memorized; it can only be imparted and absorbed. It is not reducible to rules; it only exists in practice.

Now I could give you a theory about how universities can transmit this sort of practical moral wisdom, but let's save that. Let's focus on practical wisdom in the modern workplace.

Think about Sheryl Sandberg'ss recent book, Lean In. Put aside the debate about the challenges facing women in society. Focus on the tasks she describes as being important for anybody who wants to rise in this economy: the ability to be assertive in a meeting; to disagree pleasantly; to know when to interrupt and when not to; to understand the flow of discussion and how to change people's minds; to attract mentors; to understand situations; to discern what can change and what can't.

These skills are practical knowledge. Anybody who works in a modern office knows that they are surprisingly rare. But students can learn these skills at a university, through student activities, through the living examples of their professors and also in seminars.

Nelson's venture, Minerva, uses technology to double down on seminars. Minerva is a well-financed, audacious effort to use technological advances to create an elite university at a much lower cost. I don't know if Minerva will work or not, but Nelson is surely right to focus on the marriage of technology and seminars.

The problem with the current seminars is that it's really hard to know what anybody gets out of them. The conversations might be lively, but they flow by so fast you feel as if you're missing important points and exchanges.

The goal should be to use technology to take a free-form seminar and turn it into a deliberate seminar (I'm borrowing Anders Ericsson's definition of deliberate practice). Seminars could be recorded with video-cameras, and exchanges could be reviewed and analyzed to pick apart how a disagreement was handled and how a debate was conducted. Episodes in one seminar could be replayed for another. Students could be assessed, and their seminar skills could be tracked over time.

So far, most of the talk about online education has been on technology and lectures, but the important challenge is technology and seminars. So far, the discussion is mostly about technical knowledge, but the future of the universities is in practical knowledge.