David Wiley's identification of the paradox identifying that making a learning object more re-usable, means reducing its pedagogical value
It turns out that reusability and pedagogical effectiveness are completely orthogonal to each other. Therefore, pedagogical effectiveness and potential for reuse are completely at odds with one another, unless the end user is permitted to edit the learning object. source
Or as D'Arcy Norman summarises
If a learning object is useful in a particular context, by definition it is not reusable in a different context. If a learning object is reusable in many contexts, it isn't particularly useful in any
The assumption is that pedagogical value arises from a high level of contextual knowledge.
The more context a learning object has, the more (and the more easily) a learner can learn from it. source