Undetectable Technology

Science fiction author Karl Schroeder has an interesting answer to the Fermi Paradox, which asks why there is no evidence for extraterrestrial life given the high probability for its existence:

Basically, either advanced alien civilizations don't exist, or we can't see them because they are indistinguishable from natural systems. I vote for the latter.

For the interested news reader, the distinction between what's natural and what's artificial is already blurring in the fields of biology and chemistry. It is mind-boggling, though, that the most advanced technology might be undetectable because it appears to us as natural physical phenomena.