It would be difficult to live if everything you read and heard went straight to your heart, conviction and will and didn't have to pass through that barrier of consideration and acceptance/modification/refusal and into real life-changing practice or understanding. I would either have to stop reading and listening almost altogether, or else I would find myself changing my life back and forth almost every day (and when that happens, I don't like it!)
In On Christian Doctrine St Augustine writes:
But hasty and careless readers are led astray by many and manifold obscurities and ambiguities, substituting one meaning for another; and in some places they cannot hit upon even a fair interpretation. Some of the expressions are so obscure as to shroud the meaning in the thickest darkness. And I do not doubt that all this was divinely arranged for the purpose of subduing pride by toil, and of preventing a feeling of satiety in the intellect, which generally holds in small esteem what is discovered without difficulty.
Even though he was talking specifically about Scripture, he is also talking more generally about a characteristic of human psychology -- that it needs a process and some hard work to get to what is worthwhile.
When Aidan was on total parental nutrition (getting his nutrition in primary form through an IV), his digestive process was basically bypassed. The TPN kept him alive and growing while he was waiting for his transplant (his failing liver could not process proteins) but it did not help him thrive. To thrive he needed to handle his food, to suck, to chew, to taste and digest. This not only helped his digestive system but also his oral-motor process and his knowledge of how to interact with things sensorily.
To go back to the "reading knowledge" and "real understanding" barrier, I suppose it's because we're in bodily form that we don't just understand instantly like the angels do -- we have this mental taking up, sorting, discarding and digesting process. People can't just take nutritional pills like in old sci-fi shows from the 50's and still expect to be healthy.. And people can't simply take mental pills either, it would seem. So really, I don't wish I could become educated just by knowing what's in between the pages of a book. I'm glad it takes some work and in many cases, grace and enlightenment from the Holy Spirit, to actually sort through it and make it my own.