Five years on and we're no nearer to obtaining a common understanding of the term e-learning. It seems that e-learning specialists are like economists - put any two in a room and you will generate at least three competing theories. And yet, without some common understanding, how can we expect to bring managers, learners and, most importantly, the training and teaching professions, with us in making the most of the opportunities provided by new technology.

According to my dictionary, a paradigm is a pattern or example underlying a theory or methodology. In my view we have three paradigms at play in e-learning, each engaged in at least a border dispute with the other, if not outright war. It's time they signed a peace pact and started to trade together. Let's take a look at the contestants.

Paradigm one sees e-learning as a natural evolution of good old CBT, CAI, CAL and all those other TLAs (three-letter abbreviations). CBT, computer-based training, is about delivering interactive lessons to individual students, sitting in front of their PCs. CBT has changed very little since its conception in the late 1970s; in fact many would argue that the very best work in this field took place at least twenty years ago. CBT online is almost exactly the same as CBT on CD-ROM, even on videodisc, just without most of the multimedia. If you believe that CBT is the essence of e-learning, then you might wonder why such a fuss was made about its re-launch, alongside the dotcom boom. CBT at worst has all the benefits of other self-study media (self-pacing, flexible timing, economies of scale, etc.), at best it can be adaptive to the learner's needs, engage the learner in a meaningful dialogue and present compelling games and simulations. Needless to say, we're not seeing the best.

Whereas paradigm one has its origins in corporate and military training, paradigm two comes out of further and higher education. It utilises the Internet as an alternative channel of communication for distance learning, an inexpensive way to deliver linear (non-interactive) content to geographically-dispersed learners and to enable them to engage with one another and with their tutors using standard Internet tools, such as email and forums/bulletin boards. Paradigm two scores because it mixes self-study and collaborative learning and provides the learner with continuous support. Compared to CBT, paradigm two courses are relatively inexpensive to develop. Unfortunately, because of the heavy tutorial requirement, they are as expensive to deliver in terms of faculty time as the classroom.

Paradigm two scores because it takes advantage of the Internet to bring learners and tutors together. In this respect it is genuinely new. What it doesn't do is provide the sort of live, real-time experience that learners are used to in the classroom. This takes us to paradigm three, the use of virtual classrooms. Synchronous communication is important to learners because it helps to provide structure to a course timetable (activities you must engage in at particular times), because it enables issues to be handled quickly and because it encourages social interaction. If virtual classroom software wasn't so inexplicably expensive, it would also be by far the cheapest of the three methods (you can use chat rooms and instant messaging but they don't yet provide a comparable experience).

So, three paradigms, which like religions attract their own believers and which, also like religions, can act as catalysts for confrontations. But, in essence, all three are entirely compatible; each adds something really valuable to the mix. Paradigm one provides us with the potential for compelling, interactive, multi-media content, available anytime, anywhere. Paradigm two removes the risk of learner isolation on longer courses, by allowing communities to form and all learners to be supported. Paradigm three makes the immediacy of the classroom available to learners at a distance. E-learning, which exploits computer networks to facilitate education and training, needs all three of these approaches, and so do learners. Let's face it, it's time to stop the paradigm war.

Coming soon: the fourth paradigm!