The trick of knowledge
Computational agents can be considered intelligent to the extent that they utilize human-level knowledge in their behavior. How to do that is the great difficulty. I submit that the trick of knowledge is going beyond mere possession of the facts of knowledge to the ability to know how to apply knowledge. So, if we want to encode knowledge in a form that is useful to computational agents, that encoding must also include an encoding of the knowledge of how to apply that knowledge. Sure, we can hard-wire that latter knowledge, but that may be difficult, error prone, and probably much less flexible or adaptable to evolution of the environment. And even if we are successful at that hard-wiring, that hard-wired knowledge must be properly parameterized to be used in a complex environment.
It is worth noting that even the knowledge of how to apply knowledge needs its own knowledge of how to apply that knowhow, and so on seemingly ad infinitum. Clearly at some level there must be hard-wired knowledge. Picking that level is a central challenge, but does highlight the need for a rich knowledge-based infrastructure.
In any case, the trick of knowledge is not in what you know, but in your ability to apply that knowledge. Maybe that is the essence of intelligence itself.