[kincardine]

http://en.wikipedia.org/wiki/Reification_(fallacy)

And, related...

http://en.wikipedia.org/wiki/Reification_(computer_science)

[murbard2]

That's not exactly it though. The mistake is in thinking that your idea is detailed when it merely feels detailed.

Somewhat similarly, entheogens do not really give you profound ideas so much as the feeling that the ideas you are contemplating are profound.