Something I learned early on when I learnt the causative-passive was that the sentences also make sense when you drop the causative-passive, e.g.
Basically, "it's just a nuance". Someone (possibly unnamed) made you do the action. But I recently came across this example where I'm pretty sure I can't use that line of thought:
"A novel that forces you to think".
Is this correct Japanese? 考える小説 would be "a thinking novel", so 考えさせらる小説 reads to me as "a novel that is forced to think", which of course is nonsense.
Hm, thinking about it some more, I realised, that 考える小説 may make some sense, as "books to think", or "books for thinking"? Is that the reason why 考えさせられる小説 works?