Occasionally, I get a letter from someone who is in 'contact' with extraterrestrials. I am invited to 'ask them anything'. And so over the years I've prepared a little list of questions. The extraterrestrials are very advanced, remember. So I ask things like, 'Please provide a short proof of Fermat's Last Theorem'. Or the Goldbach Conjecture. And then I have to explain what these are because extraterrestrials will not call it Fermat's Last Theorem. So I write out the simple equation with the exponents. I never get an answer. On the other hand, if I ask something like 'Should we be good?' I almost always get an answer. Anything vague, especially involving conventional moral judgements, these aliens are extremely happy to respond to. But on anything specific, where there is a chance to find out if they actually know anything beyond what most humans know, there is only silence.*

Something can be deduced from this differential ability to answer questions.

In the good old days before the alien abduction paradigm, people taken aboard UFOs were offered, so they reported, edifying lectures on the dangers of nuclear war. Nowadays, when such instruction is given, the extraterrestrials seem fixated on environmental degradation and AIDS. How is it, I ask myself, that UFO occupants are so bound to fashionable or urgent concerns on this planet?

-- C. Sagan