o Vyachesla,
You are correct that it does say itself in the Allegory that the returning prisoner would have no desire to ever return to a life within the cave, to be deceived again. Which is also why he would not become one of the shadow casters. However, in the case of using the shadows as a tool, I find your theory quite intriguing. Perhaps it would be possible, like you said starting at a level the rest of the prisoners can identify with. I believe that the returning prisoner does in fact do this. To liberate the prisoners, to convince them of the truth, he in turn asks them to for a moment question their reality. To do this he asks them to question what the shadows are, why they exist, and forces them to ponder further on the meaning of life within the cave and what may exist beyond. I do not however think that he would resort to using the shadows as the shadow casters do. This would be like a teacher trying to teach his students through a strand of lies. Much like we can not think of light without having compared it with the darkness, we too can not think of truth without first comparing it to the lie. To realize the truth we must first realize the lie. But to we are unable to realize such lies by compacting it further with deception, instead we must think of other variables that may exist in the world to counter such lies, social truths, or myths. By questioning our reality we may in turn realize another reality could possibly exist. It is by questioning our own truths that we reveal other truths may also exist. This is still a very compelling theory one which I would like to see argued out
-Platonia