This is actually an anti-rationality quote. Enigmas of the world are not harmless. Just try fighting "harmless enigmas" like diseases before germ theory. The mysteries of the world are not made terrible by our attempts to interpret them as though it had an underlying truth.

I interpret this quote to suggest that mysteries are harmless, and that trying to understand the world is what is harmful. The vast majority of the time, this view is backwards; it is falsified by the history of science. I really hope this isn't what the quote means in context, because otherwise, it is mystery mongering, and I can't even begin to fathom what is wrong with the thought process that led to it.

What we don't know can hurt us. Attempting to understand the world based on an underlying structure is at least instrumentally rational, and it might even be true, also.

I'm curious about the context of the quote, and what NihilCredo thinks it has to do with rationality.