The first caller asked if I thought aliens were walking among us in an attempt to learn the nuances of human existence. I mentioned the work of Dr. David Jacobs, a smart guy who thinks that an extraterrestrial hybridization program begun in the 1940s is now producing viable transgenic offspring who are quietly infiltrating human society. (I don't agree with Jacobs, but that's another post . . .) I offered my opinion that if advanced ETs wanted to secretly observe us they could probably do so using a form of nanotech that would elude 21st century science; disguising themselves in order to work and live among us unnoted seems unlikely.
Then again, who am I to outguess bona fide aliens? I like Whitley Strieber's telling of two apparent "visitors" in a bookstore shortly after the release of "Communion," covered in scarves, hats and sunglasses . . .
The second caller asked me if there were such things as Men In Black; I replied that there were, although exactly who these frequently bizarre characters are is the subject of debate. (Keel's "The Mothman Prophecies" and Jenny Randles' "The Truth Behind Men In Black" are probably the best books I've read on the phenomenon.)