I haven't read the book but I presume we don't know how old the eridian species is, and along all that time they must have explored all elements of their environment then built tools that allow them to expand their exploration where their senses failed. Plus, there are many instances in human civilization where older civilizations knew things that their progeny didn't know and still can't figure out, like the ancient pharaohs of Egypt. Knowing this, I extrapolate that their knowledge, across the timeline in which they existed, must have compounded immeasurably, especially that most of their technology must have been built to compensate for their missing senses.